Tuesday, 14 October 2014
Sunday, 12 October 2014
The Soviet Union is first to the Moon
Richard Cavendish explains how, on September
12th, 1959, the Soviet Union launched Luna 2, the first spacecraft to
successfully reach the Moon.
Luna 2The
space race between the United States and the Soviet Union brought an
engaging touch of science fiction to the Cold War. To American
astonishment and dismay, the Russians at first took a commanding lead.
Their programme was directed by Sergei Korolev, a brilliant aeronautical
engineer and expert on rockets, who had displeased Stalin and spent
time in the Gulag in the 1930s. He was a commanding figure who did not
suffer fools gladly and his staff treated him almost as a god. In the
1950s he developed a massive and at the time almost unthinkably powerful
rocket, the R-7, which would propel Soviet spacecraft to the Moon.Sputnik 1, the first satellite ever launched, created a sensation in 1957 when it hurtled out into space and orbited the Earth every 96 minutes before falling back into the Earth’s atmosphere. Sputnik 2 took the first living creature out into space, a sweet-tempered dog called Laika, though she did not last as long as the Russians pretended. More Sputnik missions tested life-support systems and re-entry procedures. In January 1959 the spacecraft Luna 1 (which Korolev called Mechta, ‘the Dream’) was launched at the Moon, but missed by around 3,700 miles and went into orbit between the Sun and Mars.
Then, on September 12th, 1959 Luna 2 was launched. At just past midnight Moscow time on September 14th it crashed some 240,000 miles away on the Moon not far from the Sea of Tranquillity (perhaps a not entirely appropriate location). Korolev and his people were listening as the signals coming back from the spacecraft suddenly stopped. The total silence meant that Luna had hit its target and there was great jubilation in the control room.
Luna 2 (Luna is Russian for Moon) weighed 390 kilograms. It was spherical in shape with antennae sticking out of it and carried instruments for measuring radiation, magnetic fields and meteorites. It also carried metal pendants which it scattered on the surface on impact, with the hammer and sickle of the USSR on one side and the launch date on the other. It confirmed that the moon had only a tiny radiation field and, so far as could be observed, no radiation belts. The spacecraft had no propulsion system of its own and the third and final stage of its propelling rocket crashed on the moon about half an hour after Luna 2 itself.
The scientific results of Luna 2 were similar to those of Luna 1, but the psychological impact of Luna 2 was profound. The closest any American probe had come to the Moon at that point was 37,000 miles. It seemed clear in the United States that the timing had been heavily influenced by the fact that the Soviet premier, Nikita Khruschev, was due to arrive in the US immediately afterwards, to be welcomed by President Eisenhower. Luna 2’s success enabled him to appear beaming with rumbustious pride. He lectured Americans on the virtues of communism and the immorality of scantily clothed chorus girls. The only way of annoying him seemed to be by refusing to let him into Disneyland.
Korolev had a clincher to come. Only three weeks later, Luna 3 was launched on October 4th, the second anniversary of Sputnik 1, to swing round the far side of the Moon and send back the first fuzzy pictures of its dark side, which no one had seen before. It was an astonishing feat of navigation and it was now possible to draw a tentative map of the Moon’s hidden side.
While the Americans were in disarray, with their space efforts publicly failing (Russian setbacks were kept strictly secret), Korolev went on to put the first man into space, Yuri Gagarin, in 1961. In 1963, on Khruschev’s orders, he propelled the first woman into space, Valentina Tereshkova, which enabled the Soviet Union to make propaganda mileage by claiming that under communism women were treated equally to men.
After 1961, under President Kennedy, American efforts intensified while the Soviet programme suffered from infighting after Korolev’s death at 59 in 1966, following an operation that went wrong. The Luna programme continued and in 1966, the year of Korolev’s death, Luna 9 made the first soft landing on the Moon.
In the end it was of course the Americans who won the race, in 1969, when their astronauts first walked on the Moon. For all the years of rivalry, the viewing room in Russia burst into huge applause as Neil Armstrong took the first steps. The Soviet astronaut Alexei Leonov wrote: ‘Everyone forgot that we were all citizens of different countries on Earth. That moment really united the human race.’
Saturday, 11 October 2014
Tuesday, 7 October 2014
India, four other nations to begin work on world's biggest telescope in Hawaii Island
Zee Media Bureau
New Delhi: Opening a new chapter in order to explore the universe, India along with Japan, the US, China and Canada will start work on the world's biggest telescope in Hawaii Island on Tuesday.
The 30-metre telescope, also known as TMT, will be built near the summit of the Mauna Kea volcano on Hawaii Island.
According to reports, with the help of TMT, astronomers will be able to study stars which have their origin dated 200 million to 400 million years after the Big Bang.
Around 100 astronomers and officials from these five countries will attend a ceremony in Hawaii Island to mark the beginning of the construction work.
The construction of TMT is likely to be completed by 2022.
The project would cost $1.47 billion with Japan covering about a quarter of the cost, the report said.
(With Agency inputs)
New Delhi: Opening a new chapter in order to explore the universe, India along with Japan, the US, China and Canada will start work on the world's biggest telescope in Hawaii Island on Tuesday.
The 30-metre telescope, also known as TMT, will be built near the summit of the Mauna Kea volcano on Hawaii Island.
According to reports, with the help of TMT, astronomers will be able to study stars which have their origin dated 200 million to 400 million years after the Big Bang.
Around 100 astronomers and officials from these five countries will attend a ceremony in Hawaii Island to mark the beginning of the construction work.
The construction of TMT is likely to be completed by 2022.
The project would cost $1.47 billion with Japan covering about a quarter of the cost, the report said.
(With Agency inputs)
Sunday, 5 October 2014
Voyager book (NASA mission)
On the long, strange trip they started that year, the two Voyager spacecraft would reveal that the moons orbiting Jupiter were worlds in their own right, that Saturn's fabled rings boasted intricate weaves, and that Earth was but a pale blue dot set in the vastness of space. NASA scientists believe that Voyager 1 reached a goal without precedent—interstellar space, the uncharted sea beyond the planets, the realm of stars—on August 25, 2012. The spacecraft had far outstripped Voyager 2, which trailed its twin by more than 300 million miles (483 million kilometers).
Until Voyager 1's feat, "all spacecraft, everything, all the planets, had been immersed in the solar wind, the wind from the sun," says Ed Stone, the rangy, 78-year-old Caltech professor who has headed the Voyager 1 and 2 science team for its entire 37 years of space exploration.
Voyager 1 found a distict change of neighborhood in interstellar space, where ashes from long-vanished stars float every three or so inches. It was an environment with more particles than the solar wind, the stream of charged particles forever racing off the sun's surface and into space.
Traveling
more than 38,000 miles per hour (61,000 kilometers per hour), Voyager 1
dashes through interstellar space now as easily as it plunged past the
planets.All told, Voyager 1 has traveled an arc of more than 16 billion miles (26 billion kilometers), past Jupiter's moons and Saturn's gleaming rings. Voyager 2 has sailed nearly as far and has visited Uranus and Neptune as well. No other spacecraft have revealed the secrets of so many worlds, roamed so far, or so profoundly reshaped our view of our home in the cosmos.
Both
vessels carry a copy of the "golden record," a 12-inch (30-centimeter),
gold-plated copper disk that is meant to act as a kind of Rosetta Stone
for any extraterrestrials seeking to understand life on Earth. Luck—or perhaps the serendipity of exploration, to be more exact—had indeed a lot to do with it.
Launch
John Casani, the mission's project manager, and Charley
Kohlhase, Voyager mission adviser and navigation expert, watched from a
Cape Kennedy control room as unwelcome readings reached them from the
15-stories-tall rocket climbing into space. Voyager 1 looked to be
falling short. "I was scared. We were scared," Casani recalls.Kohlhase turned to Casani, who was sitting next to him. "John, we may not be making it. We're not getting enough velocity."
Voyager 2 had already given Casani heartburn after its launch a few weeks earlier. (Despite the confusion it would create, NASA decided to launch 2 before 1, calculating that Voyager 1 would arrive at Jupiter ahead of its twin.) On Voyager 2's August 20, 1977, launch, the roll of the Titan IIIE rocket as it ascended had discombobulated the spacecraft's navigation system, triggering repeated "fail-safe" routines of the spacecraft's newfangled flight computer software, designed to look after spacecraft far from Earth.
Now with Voyager 1's launch, a tiny, initially undetected leak in a fuel line on the Titan's second stage was bleeding propellant from the massive rocket as it headed upward. Falling short meant that even if Voyager 1 made it into orbit, it wouldn't be high enough to successfully head on to its next destination, Jupiter.
"That was the whole mission, right there," Casani says. "There was nothing we could do about it—just watch."
But there was another surprise. They sat and waited for the spacecraft's third-stage Centaur rocket to coast partway around Earth to its final departure location, and then fire its engines one final time to achieve escape. The Centaur contained extra fuel, perhaps enough to make up the difference and get Voyager 1 onto the orbit it needed to begin visiting the outer planets. Casani knew, however, that burning all of a rocket's fuel might cause its empty fuel pumps to shred apart explosively.
The temperamental Centaur came within three seconds of fuel depletion, he says, before mercifully shutting itself off and sending Voyager 1 into the correct orbit, where it could fire yet another rocket stage, one built into the spacecraft, to send it to Jupiter.
"The only way I knew it was so close" to running out of fuel, says Casani, "was Charley Kohlhase telling me what was happening."
The Centaur's navigation system had been programmed to calculate how much firing it needed to reach the right orbit in flight, cut off from commands from the ground during its ascent. It had performed the corrective maneuver flawlessly on its own, burning an extra 1,200 pounds (544 kilograms) of propellant to make up the shortfall and achieve parking orbit.
Voyager 1's last-stage rocket fired without
trouble, launching the spacecraft on its first leg of the trip to
Jupiter and Saturn, while its twin, Voyager 2, was poised to take a
"Grand Tour" of the solar system, an idea centuries in the making.
The Grand Tour
Astronomy's patron saint, Galileo Galilei, first wrote in
1610 about his discovery of moons orbiting Jupiter. "Infinite thanks to
God," he wrote, "for being so kind as to make me alone the first
observer of marvels kept hidden in obscurity for all previous
centuries."
Earning
Galileo the attentions of the Roman Inquisition, his discovery of four
satellites circling Jupiter in the sky dealt a deadly blow, albeit a
long-delayed one, to the belief that the Earth was the center of the
cosmos.To Kepler we also owe the simple, elegant mathematical laws that explain how planets sweep around stars and how spacecraft can tour the planets.
In his 1609 magnum opus, Astronomia Nova,
Kepler first described the curving geometry, circles and ellipses,
followed by planets as they circumnavigate the sun and by moons as they
loop around planets."We could launch as far as Jupiter; we could not launch farther," says Kohlhase, without a simple but ingenious trick pointed to by Kepler's laws: the "gravity assist" that allowed the planet-hopping trajectories pursued by Voyager 1 and 2.
Those new trajectories were the handiwork of a UCLA graduate student named Michael Minovitch who in 1961 wrote a technical memo called "A Method for Determining Interplanetary Free-Fall Reconnaissance Trajectories." In it, he boldly proposed for the first time to steer from planet to planet by using the gravity of each world to serve as the spacecraft's rudder and sails.
As a demonstration, he showed how to send a spaceship from Earth to Venus to Earth to Mars to Saturn to Pluto to Jupiter to Earth without burning a drop of fuel. To a rider on that spaceship, it would seem like the vessel was simply falling from one planet to the next.
"If you launched a cannonball at the right speed, with the right navigation, it would swing by Jupiter, by Saturn, by Uranus, and by Neptune," Kohlhase says.
By the same token, when a tiny spacecraft nears a planet, the two objects engage in a gravitational tug of war. As usually happens in such contests, the big guy wins and the little guy goes flying. In the case of a spacecraft passing in the wake of a planet as it circles the sun, the gravity assist adds to its velocity relative to the sun and changes its direction. The flyby of Jupiter done by both Voyager spacecraft added about 22,000 miles (35,400 kilometers) per hour to their speed relative to the rest of the solar system, and sent them into sharp left turns toward Saturn.
The energy for this assistance comes at a tiny cost, a transfer of planetary inertia to the spacecraft that would cause less than a trillionth of a mile per hour decrease in the speed of the King of Planets as it circled the sun.
There is one catch. "The planets have to be in a certain alignment," Kohlhase says. "If you want to use gravity assists to go from Earth to Jupiter to Saturn to Uranus to Neptune, that happens every 176 years."
A rare planetary alignment offered gravity assists that cut the mission time by nearly 20 years.
By the late 1960s, space mission planners at NASA knew that
the right alignment was coming but would last for only three years.
("The 'Goldilocks Year' was 1977," Kohlhase says, offering the
just-right alignment of the outer planets needed for gravity assists.)
In addition to saving fuel, the speed boost provided by gravity assists
could cut the mission's duration to less than nine years, instead of the
30 or more years needed to reach Pluto using a conventional spacecraft
trajectory.
JPL and, soon enough, the public were keenly aware of the opportunity for a Grand Tour presented by the alignment, Kohlhase says. "The last time it happened before the 1977 launch was 1801. That was three years before the first locomotive." (Some of the awareness came to a giddy head with The Jupiter Effect, a 1974 best-seller that prophesied catastrophes, such as a gigantic earthquake along California's San Andreas Fault, resulting from the planetary alignment.)
As the world
watched astronauts land on the moon during the space agency's Apollo
missions from 1969 to 1972, National Research Council panels and JPL
mission planners pondered the Grand Tour mission—first proposed in
1966—to explore the outer planets of the solar system.
JPL's proposed five-spacecraft Outer Planet Grand Tour
mission would have included two Jupiter-Saturn-Pluto trips, two
Jupiter-Uranus-Neptune trips, and a Jupiter orbiter. Some of the
spacecraft would be powered by nuclear rockets, which would cut trip
times to Pluto from nine years to six.
Those plans largely fell victim to NASA budget cuts as the moon race ended, says space historian John Logsdon, author of John F. Kennedy and the Race to the Moon. Recognizing the coming cuts, the Space Science Board of the National Academy of Sciences advised against the $750 million Grand Tour plan in a 1971 report.
"Just too expensive," Stone says, summarizing the report's conclusion. With the costs spiraling, NASA canceled the Grand Tour plan at the end of that year.
"JPL came back and said, 'OK, we'll start smaller,'" Casani says.
The result was Mariner-Jupiter-Saturn 77 (MJS-77), a four-year plan to send two smaller spacecraft from the successful Mariner line of missions, which had already visited Mars, Venus, and Mercury, on to the next farther planets, Jupiter and Saturn.
"We were trying to capitalize on Mariner because it had been so successful," says Casani, who was made program manager for Voyager in 1977.
One sticking point for him was the mission's name. "I said, 'Who the hell cares about what year we launched the mission? We need a nice, crisp name,'" says Casani. "So we held a contest." A case of champagne was the reward for the winner.
On a previous Mariner mission, for example, a navigations tracker had just barely kept sight of Earth well enough to allow a Venus mission to succeed. Similar Earth trackers were planned for Voyager. "The navigation team told us that they were pretty sure it would get us to Saturn, but it would be touch and go," Casani says.
"I don't want touch and go; I had enough of touch and go at Venus," he says. "I told them I want to go to Neptune and Pluto."
At the same time, they had to stay low-key. Casani's boss, Bud Schurmeier, the $320 million mission's original program manager, yelled at him for adopting a phone extension with its final four digits spelling out "MJSU."
"He told me we have to be careful with Congress, because they had barely approved the mission. And they don't want to hear about Uranus," Casani says.
"Nobody is going to care about a phone number, I told him. And they didn't. That was my phone number until the day I retired."
By 1976, NASA headquarters "became more warmly disposed" to the possibility of a Uranus flyby, according to Henry C. Dethloff and Ronald A. Schorn, authors of Voyager's Grand Tour: To the Outer Planets and Beyond, after the space agency found it couldn't convince Congress to fund a third Voyager mission to that planet.
The reason for having two spacecraft was simple, Kohlhase says: safety. One was a spare in case the first failed to properly observe Saturn's enigmatic moon, Titan. The second largest moon in the solar system, wider than Mercury, Titan was the only one swathed in its own thick atmosphere. The curious, dense haze fascinated and puzzled the mission's scientists and played a major role in the shaping of the Voyager mission.
In fact, if Voyager 1 missed its mark in peering at Titan, the idea was that Voyager 2 would alter its path to ensure an investigation of the moon, even at the cost of forestalling a trip to Uranus and Neptune.
Two spacecraft allowed the mission to look at all four Jovian moons, both from the front side and the back side, coming and going from the planet. Similar views could be gained of some of Saturn's moons.
Also, "we didn't want to send both spacecraft too close to Jupiter," Kohlhase says. On the first-ever flyby of the planet in 1973, the Pioneer 10 probe had revealed shockingly high amounts of radiation—one million times stronger than the levels in Earth's Van Allen radiation belts—emanating from Jupiter.
"If you had been riding on the spacecraft, you would have received 500 times the lethal dose," Kohlhase says. The radiation was strong enough to trigger a false command in Pioneer 10's onboard computer, which led to the loss of a close-up picture of the moon Io. The radiation was strong enough to darken the lens of the probe's asteroid and meteoroid detector.
It also scared the Voyager mission planners. "We did a lot of things to make the spacecraft more resistant to radiation" than the earlier probes were, Kohlhase says.
All the same, they kept Voyager 2 nearly twice as far away from Jupiter as its twin, just in case.
Such restrictions dictated by the science team were a blessing in disguise for the trajectory team. The advent of digital computers meant the trajectory team had 10,000 possible trajectories to choose from as they contemplated planetary passages, but they whittled the number down to 98 after consulting with the science team. And then to two, as the mission scientists honed in on the sights they absolutely could and couldn't live without on the trip. This paring down defined the paths finally followed by Voyager 1 and Voyager 2.
Pioneer 10's encounter with Jupiter, which produced about 500 photos, also taught the team one other lesson.
"Here was a room full of reporters, an auditorium full of
reporters wanting to know what the scientists were learning: 'Please
tell us. Please tell us,'" Stone says. "I thought, 'Wow, what an
opportunity to share the whole process.'"
Maybe it was a sign of the times, but sharing the experience is just what they did.
"I
got to launch my career, literally, with Voyager," says Linda Spilker
(pictured, in red). "Talk about something so inspiring, to actually be
there and watch."
Fresh out of college and one of the newly hired women on the
Voyager team, Spilker was drawn to the discoveries promised by the
mission. Now a project scientist for the Cassini spacecraft mission
orbiting Saturn today, she recalls that when Voyager 1 and Voyager 2
launched, not a lot was known about the outer planets of our solar
system.
"If you looked in the astronomy books, they had a whole lot on Mars, but when you got to Jupiter and Saturn, especially when you got to Uranus and Neptune, they only had a little tiny bit."
Although Uranus was discovered in 1781 and Neptune in 1846, astronomers still didn't know a lot about the planets before the Voyager spacecraft visited them.
"It is truly astounding how very little we knew about the outer planets when we started," NASA imaging team chief Bradford Smith wrote in the August 1990 issue of National Geographic magazine, looking back on the trip after the Voyager 2 encounter with Neptune, the last planet visited on its tour.
Before the mission, Uranus and Neptune were drawn in textbooks as aquamarine fuzz balls with scant descriptions accompanying them. Uranus rolled on its side, unlike any other planet, but no one knew the length of its day, or of Neptune's.
JPL and, soon enough, the public were keenly aware of the opportunity for a Grand Tour presented by the alignment, Kohlhase says. "The last time it happened before the 1977 launch was 1801. That was three years before the first locomotive." (Some of the awareness came to a giddy head with The Jupiter Effect, a 1974 best-seller that prophesied catastrophes, such as a gigantic earthquake along California's San Andreas Fault, resulting from the planetary alignment.)
As the world
watched astronauts land on the moon during the space agency's Apollo
missions from 1969 to 1972, National Research Council panels and JPL
mission planners pondered the Grand Tour mission—first proposed in
1966—to explore the outer planets of the solar system.
Those plans largely fell victim to NASA budget cuts as the moon race ended, says space historian John Logsdon, author of John F. Kennedy and the Race to the Moon. Recognizing the coming cuts, the Space Science Board of the National Academy of Sciences advised against the $750 million Grand Tour plan in a 1971 report.
"Just too expensive," Stone says, summarizing the report's conclusion. With the costs spiraling, NASA canceled the Grand Tour plan at the end of that year.
"JPL came back and said, 'OK, we'll start smaller,'" Casani says.
The result was Mariner-Jupiter-Saturn 77 (MJS-77), a four-year plan to send two smaller spacecraft from the successful Mariner line of missions, which had already visited Mars, Venus, and Mercury, on to the next farther planets, Jupiter and Saturn.
"We were trying to capitalize on Mariner because it had been so successful," says Casani, who was made program manager for Voyager in 1977.
One sticking point for him was the mission's name. "I said, 'Who the hell cares about what year we launched the mission? We need a nice, crisp name,'" says Casani. "So we held a contest." A case of champagne was the reward for the winner.
"That's how it got to be Voyager, instead of MJS-77."
All the while, those mission planners were still thinking
about how to travel beyond Saturn. Anything that would unnecessarily
terminate the mission at Saturn was scrapped.On a previous Mariner mission, for example, a navigations tracker had just barely kept sight of Earth well enough to allow a Venus mission to succeed. Similar Earth trackers were planned for Voyager. "The navigation team told us that they were pretty sure it would get us to Saturn, but it would be touch and go," Casani says.
"I don't want touch and go; I had enough of touch and go at Venus," he says. "I told them I want to go to Neptune and Pluto."
At the same time, they had to stay low-key. Casani's boss, Bud Schurmeier, the $320 million mission's original program manager, yelled at him for adopting a phone extension with its final four digits spelling out "MJSU."
"He told me we have to be careful with Congress, because they had barely approved the mission. And they don't want to hear about Uranus," Casani says.
"Nobody is going to care about a phone number, I told him. And they didn't. That was my phone number until the day I retired."
By 1976, NASA headquarters "became more warmly disposed" to the possibility of a Uranus flyby, according to Henry C. Dethloff and Ronald A. Schorn, authors of Voyager's Grand Tour: To the Outer Planets and Beyond, after the space agency found it couldn't convince Congress to fund a third Voyager mission to that planet.
The reason for having two spacecraft was simple, Kohlhase says: safety. One was a spare in case the first failed to properly observe Saturn's enigmatic moon, Titan. The second largest moon in the solar system, wider than Mercury, Titan was the only one swathed in its own thick atmosphere. The curious, dense haze fascinated and puzzled the mission's scientists and played a major role in the shaping of the Voyager mission.
In fact, if Voyager 1 missed its mark in peering at Titan, the idea was that Voyager 2 would alter its path to ensure an investigation of the moon, even at the cost of forestalling a trip to Uranus and Neptune.
Two spacecraft allowed the mission to look at all four Jovian moons, both from the front side and the back side, coming and going from the planet. Similar views could be gained of some of Saturn's moons.
Also, "we didn't want to send both spacecraft too close to Jupiter," Kohlhase says. On the first-ever flyby of the planet in 1973, the Pioneer 10 probe had revealed shockingly high amounts of radiation—one million times stronger than the levels in Earth's Van Allen radiation belts—emanating from Jupiter.
"If you had been riding on the spacecraft, you would have received 500 times the lethal dose," Kohlhase says. The radiation was strong enough to trigger a false command in Pioneer 10's onboard computer, which led to the loss of a close-up picture of the moon Io. The radiation was strong enough to darken the lens of the probe's asteroid and meteoroid detector.
It also scared the Voyager mission planners. "We did a lot of things to make the spacecraft more resistant to radiation" than the earlier probes were, Kohlhase says.
All the same, they kept Voyager 2 nearly twice as far away from Jupiter as its twin, just in case.
Such restrictions dictated by the science team were a blessing in disguise for the trajectory team. The advent of digital computers meant the trajectory team had 10,000 possible trajectories to choose from as they contemplated planetary passages, but they whittled the number down to 98 after consulting with the science team. And then to two, as the mission scientists honed in on the sights they absolutely could and couldn't live without on the trip. This paring down defined the paths finally followed by Voyager 1 and Voyager 2.
Pioneer 10's encounter with Jupiter, which produced about 500 photos, also taught the team one other lesson.Maybe it was a sign of the times, but sharing the experience is just what they did.
The Outer Planets
"I
got to launch my career, literally, with Voyager," says Linda Spilker
(pictured, in red). "Talk about something so inspiring, to actually be
there and watch.""If you looked in the astronomy books, they had a whole lot on Mars, but when you got to Jupiter and Saturn, especially when you got to Uranus and Neptune, they only had a little tiny bit."
Although Uranus was discovered in 1781 and Neptune in 1846, astronomers still didn't know a lot about the planets before the Voyager spacecraft visited them.
"It is truly astounding how very little we knew about the outer planets when we started," NASA imaging team chief Bradford Smith wrote in the August 1990 issue of National Geographic magazine, looking back on the trip after the Voyager 2 encounter with Neptune, the last planet visited on its tour.
Before the mission, Uranus and Neptune were drawn in textbooks as aquamarine fuzz balls with scant descriptions accompanying them. Uranus rolled on its side, unlike any other planet, but no one knew the length of its day, or of Neptune's.
Jupiter and Saturn were thought to be
better understood: big, boring balls of gas, one adorned with a red spot
and surrounded by crater-battered ice moons, the other encircled by
uncomplicated rings built of snowballs the size of a Volkswagen minibus.
"We all knew we were going to have a journey of discovery, of
course, but none of us knew how rich it was, because none of us had any
idea the solar system was so diverse," Stone says.
"Time after time, our 'terra-centric' view was well informed, but it was much too limited," he says, with Earthly expectations confounded by every planet they met.
At Jupiter in 1979, for example, a chance observation upended long-held expectations about Io, Jupiter's innermost large moon, one of the marvels first witnessed by Galileo in 1610.
Planetary scientists had hoped to measure the craters on Io as a way to gauge the impact history of our solar system. Instead, they puzzled over its curiously mottled surface, which resembled nothing so much as an orange left to spoil in the back recess of a refrigerator. Nary a crater was there to be seen.
A chance observation on March 9, 1979, by navigation team member Linda Morabito revealed volcanoes erupting on Io, stunning everyone. "When Voyager was launched, the only active volcanoes known were here on Earth," Stone says. "And suddenly, here's a moon with ten times the volcanic activity of the Earth." All sorts of "funny clues" should have led the scientists to suspect that volcanoes ringed Io, says JPL's Torrence Johnson, but they didn't, in part because of research that pointed toward other possibilities.
For one thing, NASA and University of California planetary scientists had just published a paper in Science suggesting that Io was the "most intensely heated terrestrial-type body in the solar system." Gases were known to come from the moon. And from their own work, the mission team knew that Io's orbit around Jupiter was out-of-round, which might produce heating tides.
Influenced by the Apollo landings, however, the team thought Io was a "dead ringer," Johnson says, for Earth's moon, which had been geologically dead for billions of years.
Expecting to see a moonscape on Io, the team underexposed the first photos sent back from the moon and filtered the images to draw out the expected craters. Which didn't exist.
"We had gotten too clever," Johnson says. The filtering, it turns out, washed out all the plume activity: "a perfect anti-plume filter," he says.
So they initially missed the discovery, until Morabito observed plume shapes visible in overexposed images of the moon taken to provide a fix on guiding stars as Voyager 1 looked back over its shoulder on departure from Jupiter.
"[The plumes] were hitting you right between the eyes," Johnson says, adding dryly: "Of course, we were very imaginative; we named them P1, P2, P3…"
Seven in all. The discovery riveted the public's attention on Jupiter's moons, Galileo's storied discoveries.
"They had different histories and were worlds in their own right." Some of the volcanoes seen on Io are still smoldering today.
"Time after time, our 'terra-centric' view was well informed, but it was much too limited," he says, with Earthly expectations confounded by every planet they met.
At Jupiter in 1979, for example, a chance observation upended long-held expectations about Io, Jupiter's innermost large moon, one of the marvels first witnessed by Galileo in 1610.
Planetary scientists had hoped to measure the craters on Io as a way to gauge the impact history of our solar system. Instead, they puzzled over its curiously mottled surface, which resembled nothing so much as an orange left to spoil in the back recess of a refrigerator. Nary a crater was there to be seen.
A chance observation on March 9, 1979, by navigation team member Linda Morabito revealed volcanoes erupting on Io, stunning everyone. "When Voyager was launched, the only active volcanoes known were here on Earth," Stone says. "And suddenly, here's a moon with ten times the volcanic activity of the Earth." All sorts of "funny clues" should have led the scientists to suspect that volcanoes ringed Io, says JPL's Torrence Johnson, but they didn't, in part because of research that pointed toward other possibilities.
For one thing, NASA and University of California planetary scientists had just published a paper in Science suggesting that Io was the "most intensely heated terrestrial-type body in the solar system." Gases were known to come from the moon. And from their own work, the mission team knew that Io's orbit around Jupiter was out-of-round, which might produce heating tides.
Influenced by the Apollo landings, however, the team thought Io was a "dead ringer," Johnson says, for Earth's moon, which had been geologically dead for billions of years.
Expecting to see a moonscape on Io, the team underexposed the first photos sent back from the moon and filtered the images to draw out the expected craters. Which didn't exist.
"We had gotten too clever," Johnson says. The filtering, it turns out, washed out all the plume activity: "a perfect anti-plume filter," he says.
So they initially missed the discovery, until Morabito observed plume shapes visible in overexposed images of the moon taken to provide a fix on guiding stars as Voyager 1 looked back over its shoulder on departure from Jupiter.
"[The plumes] were hitting you right between the eyes," Johnson says, adding dryly: "Of course, we were very imaginative; we named them P1, P2, P3…"
Seven in all. The discovery riveted the public's attention on Jupiter's moons, Galileo's storied discoveries.
"They had different histories and were worlds in their own right." Some of the volcanoes seen on Io are still smoldering today.
At Saturn in 1981, similar surprises
awaited, this time from the planet's seemingly simple rings. "The ring
hunt!" Johnson says. "At the time we launched and approached Saturn, it
was the A ring, the B ring, the C ring… These are the things you can see
from Earth with a telescope. And they were all regarded as being
relatively uniform."
Once again, Voyager's findings surprised. The "gap" in
Saturn's rings, discovered in the 16th century, proved to be filled with
evenly spaced arcs of dust and ice. Some of the rings possessed spokes,
intertwined strands, and "shepherd" moons that watched over unexpected
clumps in the outer rings.
Voyager 1 also discovered the thin E ring circling Saturn along the orbit of the mysteriously smooth, icy moon, Enceladus—another puzzle.
The A ring observed for four centuries proved to be, in fact, dozens of ringlets. There were so many that imaging team leader Smith gave up counting them all for reporters at the daily briefing on Voyager 1's Saturn encounter. "You count them," he told the press corps.
Discoveries kept coming. Radio signals sent through the hazy atmosphere of Saturn's big moon, Titan, revealed that the orb's atmosphere was so thick it had fooled astronomers into thinking it was the largest satellite in the solar system. It was actually the second largest at 3,200 miles (5,150 kilometers) wide, some 60 to 70 miles (97 to 113 kilometers) skinnier than Jupiter's frozen moon, Ganymede. (Both are bigger than the planet Mercury.)
With every planetary encounter, every obstacle overcome, every discovery made, the Voyager team grew closer, with picnics and softball games binding them together as a family of sorts. In Spilker's case, the connection was profound.
"Actually, there is a whole cadre of Saturn-to-Uranus babies who would come with us to the softball games," Spilker says. "They just kind of grew up from being babies to actually playing on the softball team."
Voyager 2's departure from Saturn also saw "one of the toughest times for the team," she says, when the camera-holding platform, or scan platform, of the spacecraft jammed, leaving the cameras and other instruments fruitlessly clicking away on empty space instead of their intended targets.
"We realized: Oh, my gosh, we're stuck," says Spilker. "This is terrible."
(Among the opportunities lost was a chance to see the geysers we now know erupt from the underside of Enceladus, creating Saturn's E ring, and spokes in the other rings that would await discovery by the Cassini mission two decades later. The mission also lost a chance to shoot a photo strip of the northern half of the moon Tethys.)
Once
again the mission was in danger. Voyager 2 was flying toward Uranus
with its eyes fixed in one direction. Half of the Grand Tour was at
stake.
"The thing I was concerned about was the scan platform was
pointed in a position looking past the planet, into space," says
astronomer Ellis Miner, who was the assistant project scientist for
Voyager, Stone's right-hand man. "Immediately, I started thinking of a
way to turn it to look back at the planet."
Once again, some luck helped.
After two anxious days of trying, the engineering team discovered that very slow, stronger-than-normal turns of the scan platform allowed low-speed pointing of the cameras. They would be able to get pictures of Uranus and Neptune after all.
"We probably caused the problem," Miner says now. After Voyager 1's flight past Saturn, the team had sped up operations of Voyager 2's scan platform to take even more pictures. The rapid motions likely caused the platform's bearings to seize. Slow, careful motions seemed to work just fine, preserving plans for Uranus and Neptune.
"It would have been a whole lot better if it had been Voyager 1 that had seized at Saturn, because that was its last planetary encounter," he says.
Uranus and Neptune, of course, were always in the plans for Voyager 2, but it wasn't until Voyager 1 carefully observed the haze-shrouded mini-world Titan, Saturn's largest moon, "an enigma," Miner said, that NASA headquarters released Voyager 2 for the rest of the Grand Tour.
"Voyager was the last of the big missions that really did not have a funding problem," Miner adds. "It was so successful that when we went back to them with a request for some money to accomplish some specific thing, almost invariably they would grant it. That's unheard of in the space program."
Already a great success, Voyager 2 arced toward Uranus, while Voyage 1 pursued a faster path out of the solar system.
Voyager 2 arrived at Uranus in 1986, a fateful year for NASA.
Voyager 1 also discovered the thin E ring circling Saturn along the orbit of the mysteriously smooth, icy moon, Enceladus—another puzzle.
The A ring observed for four centuries proved to be, in fact, dozens of ringlets. There were so many that imaging team leader Smith gave up counting them all for reporters at the daily briefing on Voyager 1's Saturn encounter. "You count them," he told the press corps.
Discoveries kept coming. Radio signals sent through the hazy atmosphere of Saturn's big moon, Titan, revealed that the orb's atmosphere was so thick it had fooled astronomers into thinking it was the largest satellite in the solar system. It was actually the second largest at 3,200 miles (5,150 kilometers) wide, some 60 to 70 miles (97 to 113 kilometers) skinnier than Jupiter's frozen moon, Ganymede. (Both are bigger than the planet Mercury.)
The Flybys
"The flybys, that's the time you'd kinda spend living at
JPL," Spilker says. People would bring in sleeping bags or stay in
campers they kept in the parking lot. "You'd go into offices and there
would be these sleeping bags and these legs sticking out 'cause they
would be under their desk, sleeping, waiting for the next exciting thing
to come down."With every planetary encounter, every obstacle overcome, every discovery made, the Voyager team grew closer, with picnics and softball games binding them together as a family of sorts. In Spilker's case, the connection was profound.
"I tell my daughters their births were based on the alignments of the planets," Spilker says.
With Voyager 2 leaving Saturn in 1981 and heading for Uranus,
a five-year hiatus, she and others on the mission started their
families."Actually, there is a whole cadre of Saturn-to-Uranus babies who would come with us to the softball games," Spilker says. "They just kind of grew up from being babies to actually playing on the softball team."
Voyager 2's departure from Saturn also saw "one of the toughest times for the team," she says, when the camera-holding platform, or scan platform, of the spacecraft jammed, leaving the cameras and other instruments fruitlessly clicking away on empty space instead of their intended targets.
"We realized: Oh, my gosh, we're stuck," says Spilker. "This is terrible."
(Among the opportunities lost was a chance to see the geysers we now know erupt from the underside of Enceladus, creating Saturn's E ring, and spokes in the other rings that would await discovery by the Cassini mission two decades later. The mission also lost a chance to shoot a photo strip of the northern half of the moon Tethys.)
Once
again the mission was in danger. Voyager 2 was flying toward Uranus
with its eyes fixed in one direction. Half of the Grand Tour was at
stake.Once again, some luck helped.
After two anxious days of trying, the engineering team discovered that very slow, stronger-than-normal turns of the scan platform allowed low-speed pointing of the cameras. They would be able to get pictures of Uranus and Neptune after all.
"We probably caused the problem," Miner says now. After Voyager 1's flight past Saturn, the team had sped up operations of Voyager 2's scan platform to take even more pictures. The rapid motions likely caused the platform's bearings to seize. Slow, careful motions seemed to work just fine, preserving plans for Uranus and Neptune.
"It would have been a whole lot better if it had been Voyager 1 that had seized at Saturn, because that was its last planetary encounter," he says.
Uranus and Neptune, of course, were always in the plans for Voyager 2, but it wasn't until Voyager 1 carefully observed the haze-shrouded mini-world Titan, Saturn's largest moon, "an enigma," Miner said, that NASA headquarters released Voyager 2 for the rest of the Grand Tour.
"Voyager was the last of the big missions that really did not have a funding problem," Miner adds. "It was so successful that when we went back to them with a request for some money to accomplish some specific thing, almost invariably they would grant it. That's unheard of in the space program."
Already a great success, Voyager 2 arced toward Uranus, while Voyage 1 pursued a faster path out of the solar system.
Uranus
Voyager 2 would be Earth's first visitor to Uranus. At the
time, little was known about the planet, the fourth largest world in the
solar system, except that it was cold, aquamarine, and encircled by its
own thin, dark rings. Scientists knew that it rotated on its side with
its south pole facing the sun, but didn't know how fast it spun.Voyager 2 arrived at Uranus in 1986, a fateful year for NASA.
The spacecraft's closest encounter with
Uranus, 50,600 miles (81,500 kilometers) above its blue clouds, would
come on January 24, only four days ahead of the space shuttle Challenger
disaster, which killed seven astronauts: Mike J. Smith, Francis R.
(Dick) Scobee, Ronald E. McNair, Ellison S. Onizuka, Sharon Christa
McAuliffe, Gregory Jarvis, and Judith A. Resnik.
The Voyager team had ended its science meetings early that
day to see the launch on television, only to watch in stunned silence as
the disaster unfolded. "It was terrible," Miner says. With the entire
space agency in mourning, Voyager briefings were canceled.
Planetary scientists now believe that Miranda escaped a tidal lock it had with another of Neptune's moons, which had wracked and heated its icy interior to produce its strange surface.
Uranus also proved to have a magnetic north pole that pointed upward, toward its equator, and was off-center, another puzzle.
"Each
encounter invariably brought some surprises," Miner says. "It was our
observation that we didn't know these planets nearly as well as we
thought we did."
Neptune, the last planet on Voyager's Grand Tour, was finally
ready for its close-up in 1989. It was both a "first look and a final
farewell," as National Geographic's Rick Gore wrote that year.
Voyager found a cobalt-colored world whose serene face hid winds of 1,242 miles (2,000 kilometers) per hour, the fastest yet seen on any planet.
Its large moon, Triton, was covered with creeping frost and slush from ice volcanoes timed to the change of seasons.
Most likely, the team concluded, Triton was a refugee from
the comet belt, an ice ball that had been captured long ago by Neptune's
gravity.
Once again, Voyager opened the minds of scientists and the public to the vast variety of our solar system. No longer just points of light, every world, every moon had its own story to tell.
"It changed entirely planetary science," Miner says. "Planetary science became more like geology."
From the start, Stone had built a science team that worked cooperatively to squeeze as much science as possible out of each planetary encounter. Instrument teams competed for time to look at what they could argue was most scientifically compelling on each day of each encounter. It was a surprisingly harmonious enterprise that Miner explains was largely the result of the JPL engineering team's creativity in satisfying the scientists' demands for ever more observations.
"Many times somebody won and somebody lost," Miner says. "But we generally had so many chances we could give them their second chance."
Among them was the famous "pale blue dot" photo, showing the Earth as a tiny glint in the vastness of space. The image made real to everyone, Sagan said, what Galileo knew, what Copernicus knew, and what the women and men of Voyager knew in their bones—that we live on a tiny world, a lonely speck in the darkness.
The briefings resumed two days later. "It
was such bad news for NASA that the emphasis was on the great results
from Uranus to take away from the sorrow of the death of the
astronauts," Miner says. "It was the only good news that NASA had."
The unexpected star of the Uranus encounter was the planet's
smallest major moon, Miranda, "the most bizarre body in the solar
system," according to JPL's The Voyager Neptune Travel Guide.
Astronomers had expected the moon, discovered in 1948, to be a
crater-strewn ice ball. The moon was heavily cratered, but it was also
cut by deep cliffs and adorned with three grooved, racetrack-shaped
plains that met in chevron shapes, as if giants had chiseled
hundred-mile slabs of ice off its face.Planetary scientists now believe that Miranda escaped a tidal lock it had with another of Neptune's moons, which had wracked and heated its icy interior to produce its strange surface.
Uranus also proved to have a magnetic north pole that pointed upward, toward its equator, and was off-center, another puzzle.
"Each
encounter invariably brought some surprises," Miner says. "It was our
observation that we didn't know these planets nearly as well as we
thought we did."Voyager found a cobalt-colored world whose serene face hid winds of 1,242 miles (2,000 kilometers) per hour, the fastest yet seen on any planet.
Its large moon, Triton, was covered with creeping frost and slush from ice volcanoes timed to the change of seasons.
Once again, Voyager opened the minds of scientists and the public to the vast variety of our solar system. No longer just points of light, every world, every moon had its own story to tell.
"It changed entirely planetary science," Miner says. "Planetary science became more like geology."
From the start, Stone had built a science team that worked cooperatively to squeeze as much science as possible out of each planetary encounter. Instrument teams competed for time to look at what they could argue was most scientifically compelling on each day of each encounter. It was a surprisingly harmonious enterprise that Miner explains was largely the result of the JPL engineering team's creativity in satisfying the scientists' demands for ever more observations.
"Many times somebody won and somebody lost," Miner says. "But we generally had so many chances we could give them their second chance."
The Pale Blue Dot
As a planetary finale, at the behest of imaging team
scientist Carl Sagan, the Voyager turned its cameras backward and,
pointing in the direction of our home some 3.7 billion miles (5.9
billion kilometers) away, shot 60 images of the solar system.Among them was the famous "pale blue dot" photo, showing the Earth as a tiny glint in the vastness of space. The image made real to everyone, Sagan said, what Galileo knew, what Copernicus knew, and what the women and men of Voyager knew in their bones—that we live on a tiny world, a lonely speck in the darkness.
"On it everyone you love, everyone you
know, everyone you ever heard of, every human being who ever was, lived
out their lives," Sagan wrote. "To me it underscores our responsibility
to deal more kindly with one another, and to preserve and cherish the
pale blue dot, the only home we've ever known."
Interstellar Ambassador
On its flyby of Neptune, Voyager 2 skimmed over the northern
half of that world, poised for a close look at Triton. The gravitational
pull of the planet bent the spacecraft's path southward as it headed
out of the solar system at 33,100 miles (53,400 kilometers) per hour.Years earlier, Voyager 1 had similarly passed somewhat "beneath" Saturn when it took its close look at its moon Titan. As a result, it had headed outbound on a trajectory aimed in a northerly direction, zipping along at an even faster 37,500 miles (60,000 kilometers) per hour. The two spacecraft soon outpaced their slower predecessors, Pioneer 10 and Pioneer 11, the very first spacecraft to visit the outer planets.
For Voyager, it wasn't the end. But on Earth, the end of the Neptune encounter meant farewell for the Voyager team at JPL. Many of them moved on to the next generation of Jupiter spacecraft, the Galileo mission, or the Saturn explorer, Cassini.
After more than a decade of exploring worlds and triumphing over showstopping challenges, "we'd developed a camaraderie, more like a family than co-workers," Miner says.
"We all had the same goal," Spilker says.
"We were explorers out there wanting to do the best we could, knowing we
were going to see new things."
The Interstellar Mission
In 1990, Voyager 1 and Voyager 2 started their "interstellar
mission." In a modern-day version of finding the source of the Nile, the
spacecraft sought the edges of the solar wind."The theory for 50 years was that it had to end somewhere," says Voyager team scientist Donald Gurnett of the University of Iowa in Iowa City, who headed one instrument team. "We just didn't know where."
Past the planets, the Voyager spacecraft aim to explore
interstellar space, by first crossing the "termination shock," where the
solar wind slows abruptly, and then heading past the "heliopause,"
where the solar wind and interstellar wind meet.
The endeavor pitted the fading plutonium battery power of the spacecraft against the strength of the sun's solar wind.
Over time, radioactive decay meant that the battery power needed to operate the spacecraft's instruments was fading, from 475 watts at launch to 370 watts by the time Voyager 2 reached Neptune.
That wasn't a big deal initially, when Voyager 1 and Voyager 2 headed off on their interstellar mission. They no longer needed their power-hungry cameras, says Voyager project manager Suzanne Dodd. Dodd still heads the team of about a dozen JPL engineers carefully apportioning the juice left aboard each spacecraft. The spacecraft each lose about 4 watts of power a year.
The Voyager team chewed on a vexing question: Would the spacecraft find the edge of the solar wind before they ran out of the battery power needed for their instruments to make the discovery? The edge of the solar wind was an estimated 50 to 150 times the distance of the Earth from the sun; in comparison, Neptune orbited at 30 times that distance.
So, Voyager 1 and Voyager 2 had a ways to go.
The solar wind flows outward from the sun traveling at one million miles (1.6 million kilometers) per hour, made up of energetic particles blasted off the solar surface and into space, where the wind surrounds our star like a bubble.
In 2004, Voyager 1 entered the boundary region between the solar wind and the interstellar wind. Almost yearly, the team reported signs the spacecraft was edging closer to true interstellar space.
Making matters more complicated, however, was the breakdown in 1980 of an instrument for directly detecting that transition, which forced mission scientists to rely on indirect signs of Voyager 1 crossing into interstellar space.
Once again, the Voyager team needed to find a clever solution to their problems.
The big break came from a pair of solar storms, powerful outbursts from the sun, which caught up to the spacecraft in October 2013 and then again in April of this year. The instrument that Gurnett's team operated aboard the spacecraft, essentially a radio receiver called the plasma wave subsystem, was too weak to detect the interstellar wind. But it could measure the effects of a powerful solar storm interacting with its environment as it overtook the spacecraft.
In a report published in Science in September 2013, Gurnett's team reported that measured changes in electrical activity around Voyager did indeed correspond to interstellar space, roughly 40 times more dense than the solar wind. Based on the storm's revelations, the team extrapolated the entry date for Voyager 1 into interstellar space as August 25, 2012.
Voyager 1 delivered one last surprise, this one about our galaxy. Its data showed that the Milky Way's magnetic field is apparently aligned in the same direction as the sun's, forming what Stone calls a "magnetic highway." Space scientists had generally assumed that the galaxy's magnetic field would have some other direction.
That explained why scientists had been unable to use magnetic readings to find the edge of the solar wind and determine a starting line for interstellar space, which turned out to be nearly 125 times farther from the sun than Earth is, at 11.7 billion miles (18.8 billion kilometers). (A few scientists argue that a "magnetic reversal" will still take place for Voyager 1 before 2016. Stone and his team said they will watch for the signal, but stand by the 2012 estimate.)
How good was the Voyager science team? In their 1989 Voyager Neptune Travel Guide, produced for the last planetary encounter, they predicted that Voyager 1 would reach "mare incognito—the interstellar medium" in 2012. They nailed it, with a prediction made at a time when no one knew the distance for certain.
"It takes smart people to run a smart spacecraft," Stone says now.
Voyager 1 and Voyager 2 still have time to make a few more discoveries before their battery power fades out around 2025.
Early in July, for example, Voyager 1 recorded more "tsunami waves" from solar storms in interstellar space, electrical rumblings lashing out past the edges of the solar wind.
But in truth, of course, both spacecraft have already spoken loudly. Centuries in the making, their voyage of discovery will echo and resound, recalled forever as humanity's first journey to the edge of the solar system, and beyond.
Over time, radioactive decay meant that the battery power needed to operate the spacecraft's instruments was fading, from 475 watts at launch to 370 watts by the time Voyager 2 reached Neptune.
That wasn't a big deal initially, when Voyager 1 and Voyager 2 headed off on their interstellar mission. They no longer needed their power-hungry cameras, says Voyager project manager Suzanne Dodd. Dodd still heads the team of about a dozen JPL engineers carefully apportioning the juice left aboard each spacecraft. The spacecraft each lose about 4 watts of power a year.
The Voyager team chewed on a vexing question: Would the spacecraft find the edge of the solar wind before they ran out of the battery power needed for their instruments to make the discovery? The edge of the solar wind was an estimated 50 to 150 times the distance of the Earth from the sun; in comparison, Neptune orbited at 30 times that distance.
So, Voyager 1 and Voyager 2 had a ways to go.
The solar wind flows outward from the sun traveling at one million miles (1.6 million kilometers) per hour, made up of energetic particles blasted off the solar surface and into space, where the wind surrounds our star like a bubble.
In 2004, Voyager 1 entered the boundary region between the solar wind and the interstellar wind. Almost yearly, the team reported signs the spacecraft was edging closer to true interstellar space.
Making matters more complicated, however, was the breakdown in 1980 of an instrument for directly detecting that transition, which forced mission scientists to rely on indirect signs of Voyager 1 crossing into interstellar space.
Once again, the Voyager team needed to find a clever solution to their problems.
The big break came from a pair of solar storms, powerful outbursts from the sun, which caught up to the spacecraft in October 2013 and then again in April of this year. The instrument that Gurnett's team operated aboard the spacecraft, essentially a radio receiver called the plasma wave subsystem, was too weak to detect the interstellar wind. But it could measure the effects of a powerful solar storm interacting with its environment as it overtook the spacecraft.
In a report published in Science in September 2013, Gurnett's team reported that measured changes in electrical activity around Voyager did indeed correspond to interstellar space, roughly 40 times more dense than the solar wind. Based on the storm's revelations, the team extrapolated the entry date for Voyager 1 into interstellar space as August 25, 2012.
Voyager 1 delivered one last surprise, this one about our galaxy. Its data showed that the Milky Way's magnetic field is apparently aligned in the same direction as the sun's, forming what Stone calls a "magnetic highway." Space scientists had generally assumed that the galaxy's magnetic field would have some other direction.
That explained why scientists had been unable to use magnetic readings to find the edge of the solar wind and determine a starting line for interstellar space, which turned out to be nearly 125 times farther from the sun than Earth is, at 11.7 billion miles (18.8 billion kilometers). (A few scientists argue that a "magnetic reversal" will still take place for Voyager 1 before 2016. Stone and his team said they will watch for the signal, but stand by the 2012 estimate.)
How good was the Voyager science team? In their 1989 Voyager Neptune Travel Guide, produced for the last planetary encounter, they predicted that Voyager 1 would reach "mare incognito—the interstellar medium" in 2012. They nailed it, with a prediction made at a time when no one knew the distance for certain.
"It takes smart people to run a smart spacecraft," Stone says now.
Voyager 1 and Voyager 2 still have time to make a few more discoveries before their battery power fades out around 2025.
Early in July, for example, Voyager 1 recorded more "tsunami waves" from solar storms in interstellar space, electrical rumblings lashing out past the edges of the solar wind.
"This really is a first step for our human journey beyond Earth, beyond the planets—in fact, into interstellar space,"
Stone told comedian Stephen Colbert on his television show The Colbert Report
last December. At the show's climax, Colbert (dressed in a space suit)
presented Stone with NASA's Distinguished Public Service Medal, its
highest award for someone outside the agency. Pressed by Colbert on the
fate of the two spacecraft after 2025, Stone said the Voyager spacecraft
"will be our silent ambassadors."But in truth, of course, both spacecraft have already spoken loudly. Centuries in the making, their voyage of discovery will echo and resound, recalled forever as humanity's first journey to the edge of the solar system, and beyond.
Explore More Space >>
CREDITS
PRODUCED & DESIGNED BY
morel
MUSIC AND SOUND DESIGN BY
Tyler Strickland
RESEARCH BY
Kelsey Nowakowski
PHOTOGRAPHS BY
Ron Galella/WireImage/Getty Images (Kennedys);
CBS via Getty Images (Elvis);
Michael Ochs Archives/Handout/Getty Images (Saturday Night Fever);
NASA/JPL (Voyager 1);
NASA/National Geographic (Golden Record);
Time Life Pictures/NASA/The LIFE Picture Collection/Getty Images (Voyager 1);
NASA/JPL (Voyager 2);
NASA/JPL (Voyager 1);
Universal History Archive/Getty Images (Galileo Galilei);
Universal History Archive/Getty Images (Johannes Kepler);
NASA (moon landing video);
NASA (Jupiter, Pioneer 10);
NASA/JPL-Caltech (Linda Spilker);
NASA/JPL (Jupiter's Red Spot);
NASA/JPL (Jupiter);
NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (Giant plume from Io's Tvashtar volcano);
NASA/JPL (Saturn);
NASA/JPL (Uranus, first image);
NASA/JPL (Uranus, second image);
Apic/Getty Images (Challenger);
NASA/JPL-Caltech (Uranus's moon, Miranda);
NASA/JPL (Triton video);
NASA/JPL (Earth dot);
NASA/National Geographic (Earth). Audio courtesy Miller Center (Jimmy Carter).
ISRO Builds India's Fastest Supercomputer
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Space Capsule Successfully Recovered -isro
| January 22, 2007 |
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Since its launch, SRE-1 was going round
the earth in a circular polar orbit at an altitude of 637 km. In preparation
for its reentry, SRE-1 was put into an elliptical orbit with a perigee (nearest
point to earth) of 485 km and an apogee (farthest point to earth) of 639 km by
issuing commands from the Spacecraft Control Centre (SCC) of ISTRAC at
Bangalore on January 19, 2007. The critical de-boost operations were executed
from SCC, Bangalore supported by a network of ground stations at Bangalore,
Lucknow, Mauritius, Sriharikota, Biak in Indonesia, Saskatoon in Canada,
Svalbard in Norway besides shipborne and airborne terminals.
Today, January 22, 2007, the re-orientation
of SRE-1 capsule for de-boost operations commenced at 08:42 am (IST). The
de-boost started at 09:00 am with the firing of on-board rocket motors and the
operations were completed at 09:10 am. At 09:17 am, SRE-1 capsule was
reoriented for its re-entry into the dense atmosphere. The capsule made its
re-entry at 09:37 am at an altitude of 100 km with a velocity of 8 km/sec
(29,000 km per hour). During its reentry, the capsule was protected from the
intense heat by carbon phenolic ablative material and silica tiles on its outer
surface.
to an altitude of 5 km, aerodynamic
breaking had considerably reduced its velocity to 101 m/sec (363 km per hour).
Pilot and drogue parachute deployments helped in further reducing its velocity
to 47 m/sec (about 170 km per hour).
The main parachute was deployed at about 2
km altitude and finally, SRE-1 splashed down in the Bay of Bengal with a
velocity of 12 m/sec (about 43 km per hour) at 09:46 am. The flotation system,
which immediately got triggered, kept the capsule floating. Recovery operations
were supported and carried out by the Indian Coast Guard and Indian Navy using
ships, aircraft and helicopters.
micro gravity conditions. One of the
experiments was related to study of metal melting and crystallisation under
micro gravity conditions. This experiment, jointly designed by the Indian
Institute of Science, Bangalore and Vikram Sarabhai Space Centre,
Thiruvananthapuram, was performed in an Isothermal Heating Furnace. The second
experiment, designed by National Metallurgical Laboratory, Jamshedpur, was
intended to study the synthesis of nano-crystals under micro gravity
conditions. This experiment can help in designing better biomaterials having
closest proximity with natural biological products. The experimental results
will be analysed in due course by the principal scientific investigators of the
two experiments.
The successful launch, in-orbit operation
of the on board experiments and reentry and recovery of SRE-1 has demonstrated
India's capability in important technologies like aero-thermo structures,
deceleration and flotation systems, navigation, guidance and control. SRE-1 is
an important beginning for providing a low cost platform for micro-gravity
experiments in space science and technology and return specimen from space.
voyager mission overview
The twin
spacecraft Voyager 1 and Voyager 2 were launched by NASA in separate
months in the summer of 1977 from Cape Canaveral, Florida. As
originally designed, the Voyagers were to conduct closeup studies of
Jupiter and Saturn, Saturn's rings, and the larger moons of the two
planets.
To accomplish their two-planet mission, the spacecraft were built to last five years. But as the mission went on, and with the successful achievement of all its objectives, the additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible -- and irresistible to mission scientists and engineers at the Voyagers' home at the Jet Propulsion Laboratory in Pasadena, California.
As the spacecraft flew across the solar system, remote-control reprogramming was used to endow the Voyagers with greater capabilities than they possessed when they left the Earth. Their two-planet mission became four. Their five-year lifetimes stretched to 12 and is now near thirty years.
Eventually, between them, Voyager 1 and 2 would explore all the giant outer planets of our solar system, 48 of their moons, and the unique systems of rings and magnetic fields those planets possess.
Had the Voyager mission ended after the Jupiter and Saturn flybys alone, it still would have provided the material to rewrite astronomy textbooks. But having doubled their already ambitious itineraries, the Voyagers returned to Earth information over the years that has revolutionized the science of planetary astronomy, helping to resolve key questions while raising intriguing new ones about the origin and evolution of the planets in our solar system.
History Of The Voyager Mission
The Voyager mission was designed to take advantage of a rare geometric arrangement of the outer planets in the late 1970s and the 1980s which allowed for a four-planet tour for a minimum of propellant and trip time. This layout of Jupiter, Saturn, Uranus and Neptune, which occurs about every 175 years, allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems. The flyby of each planet bends the spacecraft's flight path and increases its velocity enough to deliver it to the next destination. Using this "gravity assist" technique, first demonstrated with NASA's Mariner 10 Venus/Mercury mission in 1973-74, the flight time to Neptune was reduced from 30 years to 12.
While the four-planet mission was known to be possible, it was deemed to be too expensive to build a spacecraft that could go the distance, carry the instruments needed and last long enough to accomplish such a long mission. Thus, the Voyagers were funded to conduct intensive flyby studies of Jupiter and Saturn only. More than 10,000 trajectories were studied before choosing the two that would allow close flybys of Jupiter and its large moon Io, and Saturn and its large moon Titan; the chosen flight path for Voyager 2 also preserved the option to continue on to Uranus and Neptune.
From the NASA Kennedy Space Center at Cape Canaveral, Florida, Voyager 2 was launched first, on August 20, 1977; Voyager 1 was launched on a faster, shorter trajectory on September 5, 1977. Both spacecraft were delivered to space aboard Titan-Centaur expendable rockets.
The prime Voyager mission to Jupiter and Saturn brought Voyager 1 to Jupiter on March 5, 1979, and Saturn on November 12, 1980, followed by Voyager 2 to Jupiter on July 9, 1979, and Saturn on August 25, 1981.
Voyager 1's trajectory, designed to send the spacecraft closely past the large moon Titan and behind Saturn's rings, bent the spacecraft's path inexorably northward out of the ecliptic plane -- the plane in which most of the planets orbit the Sun. Voyager 2 was aimed to fly by Saturn at a point that would automatically send the spacecraft in the direction of Uranus.
After Voyager 2's successful Saturn encounter, it was shown that Voyager 2 would likely be able to fly on to Uranus with all instruments operating. NASA provided additional funding to continue operating the two spacecraft and authorized JPL to conduct a Uranus flyby. Subsequently, NASA also authorized the Neptune leg of the mission, which was renamed the Voyager Neptune Interstellar Mission.
Voyager 2 encountered Uranus on January 24, 1986, returning detailed photos and other data on the planet, its moons, magnetic field and dark rings. Voyager 1, meanwhile, continues to press outward, conducting studies of interplanetary space. Eventually, its instruments may be the first of any spacecraft to sense the heliopause -- the boundary between the end of the Sun's magnetic influence and the beginning of interstellar space.
Following Voyager 2's closest approach to Neptune on August 25, 1989, the spacecraft flew southward, below the ecliptic plane and onto a course that will take it, too, to interstellar space. Reflecting the Voyagers' new transplanetary destinations, the project is now known as the Voyager Interstellar Mission.
Voyager 1 has crossed into the heliosheath and is leaving the solar system, rising above the ecliptic plane at an angle of about 35 degrees at a rate of about 520 million kilometers (about 320 million miles) a year. (Voyager 1 entered interstellar space on August 25, 2012.) Voyager 2 is also headed out of the solar system, diving below the ecliptic plane at an angle of about 48 degrees and a rate of about 470 million kilometers (about 290 million miles) a year.
Both spacecraft will continue to study ultraviolet sources among the stars, and the fields and particles instruments aboard the Voyagers will continue to explore the boundary between the Sun's influence and interstellar space. The Voyagers are expected to return valuable data for at least another decade. Communications will be maintained until the Voyagers' power sources can no longer supply enough electrical energy to power critical subsystems.
To accomplish their two-planet mission, the spacecraft were built to last five years. But as the mission went on, and with the successful achievement of all its objectives, the additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible -- and irresistible to mission scientists and engineers at the Voyagers' home at the Jet Propulsion Laboratory in Pasadena, California.
As the spacecraft flew across the solar system, remote-control reprogramming was used to endow the Voyagers with greater capabilities than they possessed when they left the Earth. Their two-planet mission became four. Their five-year lifetimes stretched to 12 and is now near thirty years.
Eventually, between them, Voyager 1 and 2 would explore all the giant outer planets of our solar system, 48 of their moons, and the unique systems of rings and magnetic fields those planets possess.
Had the Voyager mission ended after the Jupiter and Saturn flybys alone, it still would have provided the material to rewrite astronomy textbooks. But having doubled their already ambitious itineraries, the Voyagers returned to Earth information over the years that has revolutionized the science of planetary astronomy, helping to resolve key questions while raising intriguing new ones about the origin and evolution of the planets in our solar system.
History Of The Voyager Mission
The Voyager mission was designed to take advantage of a rare geometric arrangement of the outer planets in the late 1970s and the 1980s which allowed for a four-planet tour for a minimum of propellant and trip time. This layout of Jupiter, Saturn, Uranus and Neptune, which occurs about every 175 years, allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems. The flyby of each planet bends the spacecraft's flight path and increases its velocity enough to deliver it to the next destination. Using this "gravity assist" technique, first demonstrated with NASA's Mariner 10 Venus/Mercury mission in 1973-74, the flight time to Neptune was reduced from 30 years to 12.
While the four-planet mission was known to be possible, it was deemed to be too expensive to build a spacecraft that could go the distance, carry the instruments needed and last long enough to accomplish such a long mission. Thus, the Voyagers were funded to conduct intensive flyby studies of Jupiter and Saturn only. More than 10,000 trajectories were studied before choosing the two that would allow close flybys of Jupiter and its large moon Io, and Saturn and its large moon Titan; the chosen flight path for Voyager 2 also preserved the option to continue on to Uranus and Neptune.
From the NASA Kennedy Space Center at Cape Canaveral, Florida, Voyager 2 was launched first, on August 20, 1977; Voyager 1 was launched on a faster, shorter trajectory on September 5, 1977. Both spacecraft were delivered to space aboard Titan-Centaur expendable rockets.
The prime Voyager mission to Jupiter and Saturn brought Voyager 1 to Jupiter on March 5, 1979, and Saturn on November 12, 1980, followed by Voyager 2 to Jupiter on July 9, 1979, and Saturn on August 25, 1981.
Voyager 1's trajectory, designed to send the spacecraft closely past the large moon Titan and behind Saturn's rings, bent the spacecraft's path inexorably northward out of the ecliptic plane -- the plane in which most of the planets orbit the Sun. Voyager 2 was aimed to fly by Saturn at a point that would automatically send the spacecraft in the direction of Uranus.
After Voyager 2's successful Saturn encounter, it was shown that Voyager 2 would likely be able to fly on to Uranus with all instruments operating. NASA provided additional funding to continue operating the two spacecraft and authorized JPL to conduct a Uranus flyby. Subsequently, NASA also authorized the Neptune leg of the mission, which was renamed the Voyager Neptune Interstellar Mission.
Voyager 2 encountered Uranus on January 24, 1986, returning detailed photos and other data on the planet, its moons, magnetic field and dark rings. Voyager 1, meanwhile, continues to press outward, conducting studies of interplanetary space. Eventually, its instruments may be the first of any spacecraft to sense the heliopause -- the boundary between the end of the Sun's magnetic influence and the beginning of interstellar space.
Following Voyager 2's closest approach to Neptune on August 25, 1989, the spacecraft flew southward, below the ecliptic plane and onto a course that will take it, too, to interstellar space. Reflecting the Voyagers' new transplanetary destinations, the project is now known as the Voyager Interstellar Mission.
Voyager 1 has crossed into the heliosheath and is leaving the solar system, rising above the ecliptic plane at an angle of about 35 degrees at a rate of about 520 million kilometers (about 320 million miles) a year. (Voyager 1 entered interstellar space on August 25, 2012.) Voyager 2 is also headed out of the solar system, diving below the ecliptic plane at an angle of about 48 degrees and a rate of about 470 million kilometers (about 290 million miles) a year.
Both spacecraft will continue to study ultraviolet sources among the stars, and the fields and particles instruments aboard the Voyagers will continue to explore the boundary between the Sun's influence and interstellar space. The Voyagers are expected to return valuable data for at least another decade. Communications will be maintained until the Voyagers' power sources can no longer supply enough electrical energy to power critical subsystems.
voyager informaition list
| PLANETS | DIAMETER | |
| Jupiter | 142,984 km 88,846 mi |
778,000,000 km 483,000,000 mi |
| JUPITER'S MOONS | DIAMETER | DISTANCE FROM PLANET CENTER |
| Metis | 40 km 25 mi |
128,000 km 79,500 mi |
| Adrastea | 24x20x14 km 14x12x9 mi |
129,000 km 80,100 mi |
| Amalthea | 181,300 km 112,600 mi |
|
| Thebe | 110x90km 65x55 mi |
222,000 km 138,000 mi |
| Io | 3,630 km 2,225 mi |
422,000 km 262,000 mi |
| Europa | 3,138 km 1,949 mi |
661,000 km 414,500 mi |
| Ganymede | 5,262 km 3,269 mi |
1,070,000 km 664,900 mi |
| Callisto | 4,800 km 3,000 mi |
1,883,000 km 1,170000 mi |
| Leda | 16 km 10 mi |
11,094,000 km 6,900,000 mi |
| Himalia | 186 km 115 mi |
11,480,000 km 7,133,000 mi |
| Lysithia | 36 km 20 mi |
11,720,000 km 7,282,000 mi |
| Elara | 76 km 47 mi |
11,737,000 km 7,293,000 mi |
| Ananke | 30/18 mi | 21,200,000 km 13,173,000 mi |
| Carme | 40 km 25 mi |
22,600,000 km 14,043,000 mi |
| Pasiphae | 50 km 31 mi |
23,500,000 km 14,602,000 mi |
| Sinope | 36 km 22 mi |
23,700,000 km 14,727,000 mi |
| PLANETS | DIAMETER | DISTANCE FROM SUN |
| Saturn | 120,536 km 74,900 mi |
1.4 billion km 870 million mi |
| SATURN'S MOONS | DIAMETER | DISTANCE FROM PLANET CENTER |
| Atlas | 40x20 km 24x12 mi |
137,670 km 85,500 mi |
| Prometheus | 140x100x80 km 85x60x50 mi |
139,353 km 86,600 mi |
| Pandora | 110x90x80 km 70x55x50 mi |
141,700 km 88,500 mi |
| Epimetheus | 140x120x100 km 85x70x60 mi |
151,472 km 94,124 mi |
| Janus | 220x200x160 km 135x125x100 mi |
151,422 km 94,093 mi |
| Mimas | 392 km 243 mi |
185,520 km 115,295 mi |
| Enceladus | 520 km 320 mi |
238,020 km 147,900 mi |
| Tethys | 1,060 km 660 km |
294,660 km 183,100 mi |
| Telesto | 34x28x26 km 20x17x16 mi |
294,660 km 183,100 mi |
| Calypso | 34x22x22 km 20x13x13 mi |
294,660 km 183,100 mi |
| Dione | 1,120 km 695 mi |
377,400 km 234,500 mi |
| Helene | 36x32x30 km 22x20x19 mi |
377,400 km 234,900 mi |
| Rhea | 1,530 km 950 mi |
527,040 km 327,500 mi |
| Titan | 5,150 km 3,200 mi |
1,221,860 km 759,300 mi |
| Hyperion | 410x260x220 km 250x155x135 mi |
1,481,000 km 920,300 mi |
| Iapetus | 1,460 km 910 mi |
3,560,830 km 2,212,900 mi |
| Phoebe | 220 km 135 mi |
12,952,000 km 8,048,000 mi |
| PLANETS | DIAMETER | DISTANCE FROM SUN |
| Uranus | 51,118 km 31,764 mi |
3 billion km 1.8 billion mi |
| URANUS'S MOONS | DIAMETER | DISTANCE FROM PLANET CENTER |
| Cordelia | 26 km 16 mi |
49,800 km 30,950 mi |
| Ophelia | 30 km 18 mi |
53,800 km 33,400 mi |
| Bianca | 42 km 26 mi |
59,200 km 36,800 mi |
| Juliet | 62 km 38 mi |
61,800 km 38,400 mi |
| Desdemona | 54 km 33 mi |
62,700 km 38,960 mi |
| Rosalind | 84 km 52 mi |
64,400 km 40,000 mi |
| Portia | 108 km 67 mi |
66,100 km 41,100 mi |
| Cressida | 54 km 32 mi |
69,900 km 43,400 mi |
| Belinda | 66 km 40 mi |
75,300 km 46,700 mi |
| Puck | 154 km 95 mi |
86,000 km 53,000 mi |
| Miranda | 472 km 293 mi |
129,900 km 80,650 mi |
| Ariel | 1,158 km 720 mi |
190,900 km 118,835 mi |
| Umbriel | 1,172 km 728 mi |
265,969 km 165,300mi |
| Titania | 1,580 km 981 mi |
436,300 km 271,100mi |
| Oberon | 1,524 km 947 mi |
583,400 km 362,500 mi |
| PLANETS | DIAMETER | DISTANCE FROM SUN |
| Neptune | 49,528 km 30,776 mi |
4.5 billion km 2.7 billion mi |
| NEPTUNE'S MOONS | DIAMETER | DISTANCE FROM PLANET CENTER |
| Naiad | 54 km 33 mi |
48,000 km 29,827 mi |
| Thalassa | 80 km 50 mi |
50,000 km 31,000 mi |
| Despina | 180 km 110 mi |
52,500 km 32,600 mi |
| Galatea | 150 km 95 mi |
62,000 km 38,525 mi |
| Larissa | 190 km 120 mi |
73,600 km 45,700 mi |
| Proteus | 400 km 250 mi |
117,600 km 73,075 mi |
| Triton | 2,700 km 1,680 mi |
354,760km 220,500 mi |
| Nereid | 340 km 210 mi |
5,509,090 km 3,423,000 mi |
Voyager Time Line (USA)
| DATE | MILESTONE |
| 1977 | Mariner Jupiter/Saturn 1977 is renamed Voyager |
| 1977 Aug. 20 | Voyager 2 launched from Kennedy Space Flight Center |
| 1977 Sept. 5 | Voyager 1 launched from Kennedy Space Flight Center Voyager 1 returns first spacecraft photo of Earth and Moon |
| 1979 Mar. 5 | Voyager 1 makes its closest approach to Jupiter |
| 1979 July 9 | Voyager 2 makes its closest approach to Jupiter |
| 1980 Nov. 12 | Voyager 1 flies by Saturn Voyager 1 begins its trip out of the Solar System |
| 1981 Aug. 25 | Voyager 2 flies by Saturn |
| 1982 | Deep Space Network upgrades two 26-m antennas to 34-m |
| 1986 Jan. 24 | Voyager 2 has the first-ever encounter with Uranus Deep Space Network begins expansion of 64-m antennas to 70-m |
| 1987 | Voyager 2 "observes" Supernova 1987A |
| 1988 | Voyager 2 returns first color images of Neptune |
| 1989 Aug. 25 | Voyager 2 is the first spacecraft to observe Neptune Voyager 2 begins its trip out of the Solar System, below the ecliptic plane |
| 1990 Jan. 1 | Begins Voyager Interstellar Mission |
| 1990 Feb. 14 | Last Voyager Images - Portrait of the Solar System |
| 1998 Feb. 17 | Voyager 1 passes Pioneer 10 to become the most distant human-made object in space |
| 2004 Dec. 15 | Voyager 1 crosses Termination Shock |
| 2007 Sep. 5 | Voyager 2 crosses Termination Shock |
| 2012 Aug. 25 | Voyager 1 enters Interstellar Space |
Saturday, 4 October 2014
Missions to Mars
Active missions: MAVEN - Mars Orbiter Mission - Curiosity - Mars Reconnaissance Orbiter - Mars Exploration Rover Opportunity - Mars Exploration Rover Spirit - Mars Express - 2001 Mars Odyssey
Future missions: ExoMars - InSight
Past missions: Phobos-Grunt - Yinghuo-1 - Phoenix - Mars Exploration Rover Spirit - Mars Polar Lander - Nozomi - Mars Climate Orbiter - Mars Pathfinder & Sojourner - Mars 96 - Mars Global Surveyor - Mars Observer - Phobos 2 - Phobos 1 - Viking program - Mars 4, 5, 6, & 7 - Mars 2 & 3 - Mariner 9 - Kosmos 419 - Mariner 8 - Mars 1969a &b - Mariner 6 & 7 - Zond 2 - Mariner 4 - Mariner 3- Mars 1 - Korabl 11 & 13 - Korabl 4 & 5
Active Missions
MAVEN
Future Mars orbiter (NASA)Launch: November 18, 2014
Arrival: September 2014
MAVEN, which stands for Mars Atmosphere and Volatile Evolution mission, will provide first-of-its-kind measurements and address key questions about Mars climate and habitability and improve understanding of dynamic processes in the upper Martian atmosphere and ionosphere.
Links: All Planetary.org Coverage - NSSDC - Wikipedia - NASA - Facebook - Twitter
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Mars Orbiter Mission (MOM)
Future Mars orbiter (ISRO)Launch: November 5, 2013
Arrival: September 2014
Sometimes referred to by the nickname "Mangalyaan," the Mars Orbiter Mission is India's first interplanetary spacecraft. It is primarily a technology demonstration mission that carries a small, 15-kilogram payload of 5 science instruments. It is scheduled to enter orbit at Mars in September 2014. The orbit will be highly elliptical, from 387 to 80,000 kilometers.
Links: All Planetary.org Coverage - ISRO website - Facebook page - Wikipedia - nasaspaceflight.com - unmannedspaceflight.com
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Curiosity (Mars Science Laboratory) (MSL)
Roving Mars (NASA)Launch: 26 Nov 2011
Mars arrival: 6 Aug 2012
Curiosity is the next generation of rover, building on the successes of Spirit and Opportunity. It is twice as long and three times the weight of the Mars Exploration Rovers. It landed in Gale crater.
Links: All Planetary.org Coverage - NSSDC - Wikipedia - JPL - UnmannedSpaceflight
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Mars Reconnaissance Orbiter
In orbit at Mars (NASA)Launch: August 12, 2005
Mars arrival: March 10, 2006
Mars Reconnaissance Orbiter is searching for evidence of past water on Mars, using the most powerful camera and spectrometer ever sent to Mars. Its cameras are also helping in the search for landing sites for future Mars rovers and landers.
Links: All Planetary.org Coverage - NSSDC - Wikipedia - JPL - HiRISE images - MARCI weather reports
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Mars Exploration Rover Opportunity
Currently roving across Mars (NASA)Launch: July 7, 2003
Landing: January 24, 2004
Opportunity landed in Meridiani Planum at 354.4742°E, 1.9483°S, immediately finding the hematite mineral that had been seen from space by Mars Global Surveyor. After roving more than 33 kilometers, Opportunity arrived at the 22-kilometer-diameter crater Endeavour, a target it is currently exploring.
Links: Planetary Society MER Updates - NSSDC - Wikipedia - JPL - UnmannedSpaceflight
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Mars Express and Beagle 2
Currently in orbit at Mars; failed lander (ESA)Launch: June 2, 2003
Mars arrival: December 26, 2003
Five days before its arrival Mars Express successfully pushed off the tiny, 30-kilogram Beagle 2 geochemical lander. Although it had functioned successfully throughout cruise, the lander was never heard from again. Beagle 2 may have landed too hard, the victim of an unexpectedly thin atmosphere at the time of its arrival.
Mars Express successfully entered orbit on December 26 and immediately began returning stunning, 3D, color images. Mars Express has detected surprising concentrations of methane and evidence for recent volcanism on Mars. Its radar sounder, MARSIS, was deployed late in the mission due to spacecraft safety concerns, but is functioning well.
Links: NSSDC - Wikipedia - ESA - HRSC images
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2001 Mars Odyssey
Currently in orbit at Mars (NASA)Launch: April 7, 2001
Mars arrival: October 24, 2001
2001 Mars Odyssey is capturing images of the Martian surface at resolutions between those of Viking and Mars Global Surveyor, and is making both daytime and nighttime observations of the surface in thermal infrared wavelengths at resolutions higher than ever before. It has detected massive deposits of water lying below Mars’ surface in near-polar regions and widespread deposits of olivine across the planet, indicating a dry past for Mars. The MARIE instrument measured the radiation environment at Mars to determine its potential impact on human explorers, and found them to be 2 to 3 times higher than expected. 2001 Mars Odyssey also serves as a communications relay for Opportunity.
Links: All Planetary.org Coverage - NSSDC - Wikipedia - JPL - THEMIS images
Past Missions
Phobos-Soil (Phobos-Grunt)
Failed sample return mission to Phobos (Russia)Launch: January 15, 2012
Phobos-Grunt's modified Fregat upper stage of failed to ignite after launch, and the spacecraft crashed into the southern Pacific ocean.
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Yinghuo-1
Future Mars orbiter (China)Launch: January 15, 2012, piggybacked on Phobos-Grunt
Yinghuo-1 crashed with Phobos-Grunt.
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Phoenix
Successful lander (NASA)Launch: August 4, 2007
Mars arrival: May 25, 2008
Last communication: November 2, 2008
Phoenix landed near Mars' north pole to study the water ice found close to the surface there. Its arm dug trenches into the soil and delivered samples to sophisticated chemical analysis instruments.
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Mars Exploration Rover Spirit
Successful Mars rover (NASA)Launch: June 10, 2003
Landing: January 3, 2004
Contact lost: March 22, 2010
Spirit landed on Mars within Gusev crater at 14.5718°S, 175.4785° E. The initial panorama showed a rock-strewn site similar to Pathfinder’s. Spirit had to rove several kilometers across Mars and into its extended mission before it found evidence for past water. It was hobbled by one stuck wheel for many years and finally became stuck in fluffy sand.
You can read a detailed history of Spirit's mission in our MER Updates section.
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Mars Polar Lander
Failed Mars lander & 2 penetrators (NASA)Launch: January 3, 1999
Attempted landing: December 3, 1999
When Mars Polar Lander arrived at Mars, it turned its antenna away from Earth to prepare for its entry into the Martian atmosphere. This was the last time controllers heard from the spacecraft. A review board determined the most likely cause for the loss of mission was a faulty software system that may have triggered the retrorockets to turn off early, causing the lander to crash. The spacecraft had carried The Planetary Society’s Mars Microphone to Mars, the first privately funded hardware provided to a planetary mission. Two microprobes, Amundsen and Scott, were piggy-backed on the lander and expected to separate just before the lander entered the atmosphere. However, no signal was ever received from the probes.
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Nozomi ???
also known as Planet-B
Failed Mars orbiter (ISAS)Launch: July 3, 1998
Mars flyby: December 14, 2003
Originally scheduled to arrive at Mars in October 1999, Nozomi failed to gain enough speed during an Earth flyby on December 21, 1998. The spacecraft also used much more fuel than predicted. A looping trajectory was developed, including two more Earth flybys, to return Nozomi to Mars for orbit insertion in December 2003. But on April 21, 2002, a powerful solar flare damaged Nozomi’s computer. As a result, Nozomi’s hydrazine fuel froze during the long interplanetary trek and mission controllers were unable to place it into orbit. Nozomi flew by Mars at a distance of 1,000 kilometers (600 miles), and is now in a 2-year orbit around the Sun.
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Mars Climate Orbiter
Failed Mars orbiter (NASA)Launch: December 11, 1998
Mars Climate Orbiter was lost on September 23, 1999, when a mathematical conversion error placed the spacecraft too close to Mars at the time of orbital insertion. Mars Climate Orbiter carried a few re-flown instruments from Mars Observer, marking the second failures for those experiments.
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Mars Pathfinder & Sojourner
Successful Mars lander & rover (NASA)Launch: December 4, 1996
Mars arrival: July 4, 1997
Mars Pathfinder’s successful airbag-assisted landing was the first successful mission to the Martian surface since Viking, 20 years earlier. The landing site was near the mouth of Ares Vallis, at 19.33°N, 33.55°W. On July 6, 1997, the six-wheeled rover, named Sojourner in a Planetary Society-run contest, rolled off a ramp and onto the Martian surface. The lander, now named the Sagan Memorial Station for The Planetary Society's co-founder Carl Sagan, returned many images as well as weather data. The original mission was scheduled to last for 30 days, but the lander and Sojourner continued to transmit data until September 27, 1997 when contact with the lander was lost.
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Mars 96
Failed Mars orbiter, lander, & 2 penetrators (Russian Space Agency)Launch: November 16, 1996
The rocket carrying the spacecraft launched successfully, but its fourth stage ignited prematurely and sent the spacecraft crashing into the ocean. Several of the science instruments originally built for Mars 96 were later flown on ESA’s Mars Express.
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Mars Global Surveyor
Highly successful orbiter (NASA)Launch: November 7, 1996
Mars arrival: September 12, 1997
Mars Global Surveyor was the first completely successful Mars orbiter since Viking 1 shut down in 1980. The start of Mars Global Surveyor’s science mission was delayed due to a problem with one of its solar panels that caused its aerobraking period (which reduced its initial orbit from an ellipse to a low-altitude, near circular one) to last for a year and a half. Since science operations began in March 1999, Mars Global Surveyor provided scientists with a wealth of images and data, including the highest-resolution images yet achieved from orbit. Many of the Mars Observer instruments were re-flown on Mars Global Surveyor. Its mission was extended three times. Contact was lost on November 5, 2006.
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Mars Observer
Failed Mars orbiter (NASA)Launch: September 25, 1992
Mars Observer was designed to study the Red Planet from orbit. On August 21, 1993, only three days away from Mars, all contact with the spacecraft was suddenly lost. Scientists were unable to determine the cause of the failure. It is possible that Mars Observer followed its onboard program and is in orbit around Mars. However, the results of failure investigations suggest that a fuel line ruptured during tank pressurization, which would have caused the spacecraft to spin uncontrollably and fail to enter orbit. Most of the science instruments that were originally built for Mars Observer were eventually “re-flown” on subsequent orbiters.
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Phobos 2
Mostly failed Mars orbiter & 2 Phobos landersLaunch: July 12, 1988
Mars arrival: January 29, 1989
Phobos 2 was designed to orbit Mars and land a "hopper" and a lander on the surface of Phobos. The spacecraft successfully went into orbit and began sending back preliminary data. Then, on March 27, 1989, just before the spacecraft was to move within 50 meters of Phobos and deploy the two landers, the spacecraft's onboard computer malfunctioned and the mission was lost.
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Phobos 1
Failed Mars orbiter (USSR)Launch: July 7, 1988
Phobos 1 was designed to study the Sun and interplanetary space while on its way to Mars. Once in orbit around Mars, it was going to study the Red Planet and take close-up images of its moon Phobos. However, on September 2, 1988, only two months in to the flight, controllers on the ground accidentally uploaded software containing a command that deactivated the spacecraft's attitude control thrusters. The spacecraft then turned its solar panels away from the Sun and was unable to recharge its batteries. As a result, the mission was lost.
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Viking 2
Successful orbiter & lander (NASA)Launch: September 9, 1975
Mars arrival: August 7, 1976
Mars landing: September 3, 1976
The Viking 2 lander touched down in the Utopia Planitia, on the opposite side of the planet and almost 1,500 kilometers closer to the north pole than Viking 1 at 47.27°N, 225.99°W. One of the lander's legs settled down on a rock, so the entire lander was tilted by about 8 degrees. The lander took extensive atmospheric readings and conducted experiments on soil samples that it had collected with a scoop. The Viking 2 lander quit operating on April 11, 1980, when its batteries failed, but it lasted long enough to see multiple winters come to its landing site and to see it cover with frost. The Viking 2 orbiter was shut down on July 25, 1978, after 706 orbits. The Viking 1 and 2 landers returned 1,400 images from the Martian surface. The orbiters took 50,000 images, producing a global atlas that is still used today.
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Viking 1
Successful orbiter & lander (NASA)Launch: August 20, 1975
Mars arrival: June 19, 1976
Mars landing: July 20, 1976
When Viking 1 entered orbit at Mars, it began taking pictures of the surface in search of a safe landing site for the lander. Mission planners were hoping for a July 4th landing, but the original site turned out to be too rocky. Another site was chosen and the first successful Mars landing took place on July 20, 1976, the seventh anniversary of the first Moon landing. Viking 1 landed in Chryse Planitia at 22.48°N, 49.97°W. The lander took extensive weather readings and conducted experiments on soil samples collected with a scoop. The orbiter was powered down on August 17, 1980 after 1,400 orbits. The lander survived on the surface until November 13, 1982.
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Mars 4, 5, 6, and 7
Under pressure from the developing Viking mission, the USSR attempted one last time to beat the USA to a successful soft landing on Mars in 1973. Because of an unfavorable launch window, however, orbiters and landers were launched separately. All four spacecraft were hurried to completion and launched to Mars with microchips known to have serious problems. The problems mostly doomed the missions, but Mars 4, 5, and 6 all successfully performed radio occultation experiments of Mars’s atmosphere, proving the existence of an ionosphere at Mars and resulting in the measurement of a 6.7-millibar surface atmospheric pressure.^ Back to top
Mars 4
Failed Mars orbiter attempt (successful as a flyby) (USSR)
Launch: July 21, 1973
Mars flyby: February 10, 1974
The microchip problem caused the failure of the Mars 4 orbiter to fire its orbit insertion rockets. It flew by Mars at a distance of 2,200 kilometers (1,370 miles), taking one set of images and collecting limited data. It continued to function after the flyby, returning data from solar orbit.
Mars 5
Initially successful Mars orbiter, failed after 22 days
Launch: July 25, 1973
Mars arrival: February 12, 1974
Mars 5 entered orbit successfully, but after completing 22 orbits and returning 60 images the spacecraft malfunctioned and the mission ended.
Mars 6
Slightly successful descent craft and flyby
Launch: August 5, 1973
Mars arrival: March 12, 1974
The Mars 6 descent craft separated successfully from the main spacecraft and descended through the atmosphere, transmitting 224 seconds of data before abruptly cutting off (either when the retrorockets fired or when it slammed into the ground). Although this was the first data of its kind (from within the Martian atmosphere), most of it was garbled and unusable due to the microchip problem. Mars 6 landed at 23.90°S, 19.42°W.
Mars 7
Failed descent attempt
Launch: August 9, 1973
The Mars 7 lander separated too early, and it missed the planet by 1,300 kilometers (800 miles).
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Mars 2
Successful Mars orbiter and failed descent craft (USSR)Launch: May 19, 1971
Mars arrival: November 27, 1971
Mars 3
Somewhat successful Mars orbiter and very briefly successful descent craft (USSR)Launch: May 28, 1971
Mars arrival: December 2, 1971
The identical Mars 2 and Mars 3 spacecraft each released descent craft 4.5 hours prior to their arrivals at Mars. But the landers had the misfortune of arriving at Mars during one of the greatest dust storms in recorded history. The Mars 2 probe descended at a steeper angle and faster rate than intended and crashed near 45°S, 313°W. However, the Mars 3 probe used aerobraking, parachutes, and retrorockets to descend successfully to a soft landing near 45°S, 158°W. It operated for 20 seconds on the surface before mysteriously failing, possibly because it was blown over by the wind. Before failing, Mars 3 may have deployed the first tiny rover onto the surface of Mars. The Mars 2 orbiter was successfully placed in an 18-hour orbit. The spacecraft completed 362 orbits. The Mars 3 orbiter, short on fuel, was unable to obtain its intended 18-hour orbit. Instead, the spacecraft ended up in an almost 13-day orbit around the planet and completed only 20 orbits. Both spacecraft were shut down on August 22, 1972. Together, Mars 2 & 3 returned 60 images of Mars, recorded temperatures ranging from -110 to 13 degrees Celsius (-166 to 55 degrees Fahrenheit), produced surface relief maps and studied the Martian gravity and magnetic fields.
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Mariner 9
Successful Mars orbiter (NASA)Launch: May 30, 1971
Mars arrival: November 14, 1971
Mariner 9 was the first spacecraft to go into orbit around another planet. However, excitement for its arrival was subdued by a dark cloud -- literally. A Martian dust storm, which had started in late September 1971, had grown to cover the entire planet. When Mariner 9 arrived in November, the only surface features visible were the summit of Olympus Mons and the three volcanoes of Tharsis Ridge. Mission scientists had to wait about a month and a half until the dust settled before they could begin the science portion of the mission. When the spacecraft ran out of fuel almost a year later (on October 27, 1972), Mariner 9 had taken a total of 7,329 images of Mars, studied the atmospheric and surface composition of the planet, the density and pressure of its atmosphere as well as the planet's gravity and topography. The spacecraft also provided scientists with the first close-up views of Phobos and Deimos, the two moons of Mars.
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Kosmos 419
Failed Mars orbiter attempt (USSR)Launch: May 10, 1971
Kosmos 419 reached Earth orbit, but its fourth stage rocket, which would have sent the spacecraft on its way to Mars, failed to ignite. The spacecraft re-entered the atmosphere and was destroyed.
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Mariner 8
Failed Mars flyby attempt (NASA)Launch: May 8, 1971
Mariner 8, a twin to the successful Mariner 9, failed to reach Earth orbit.
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Mars 1969B
Failed Mars orbiter attempt (USSR)Launch: April 2, 1969
The first stage of the rocket launching this mission to Mars failed almost immediately after liftoff.
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Mars 1969A
Failed Mars orbiter attempt (USSR)Launch: March 27, 1969
The third stage of the rocket launching this mission to Mars failed, caught fire, and exploded, causing the remaining pieces to crash land back on Earth.
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Mariner 6
Successful Mars flyby (NASA)Launch: February 24, 1969
Mars flyby: July 31, 1969
Mariner 7
Successful Mars flyby (NASA)Launch: March 27, 1969
Mars flyby: August 5, 1969
Mariner 6 and 7 were identical spacecraft arriving at Mars five days apart. Mariner 6 flew by Mars at an altitude of 3,431 kilometers (2,131 miles) and Mariner 7 at 3,430 kilometers (2,131 miles). Mariner 6 returned 75 images, and Mariner 7 126 images. Data from the twin spacecraft helped establish the mass, radius, and shape of Mars and revealed that its southern polar ice cap was composed of carbon dioxide. The spacecraft are now in solar orbits.
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Zond 2
Failed Mars flyby and descent craft attempt (USSR)Launch: November 30, 1964
Controllers lost contact with Zond 2 after a mid-course correction maneuver while the spacecraft was on its way to Mars. The spacecraft is now in a solar orbit.
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Mariner 4
Successful Mars flyby (NASA)Launch: November 28, 1964
Mars flyby: July 14, 1965
Mariner 4 was the first spacecraft to fly by Mars and obtain close-up pictures of the Red Planet, passing within 9,844 kilometers (6,117 miles) of Mars. It then took four days to transmit the data back to Earth. Mariner 4 imaged a large, ancient crater on Mars and confirmed the existence of a thin Martian atmosphere composed largely of carbon dioxide. Once past Mars, the spacecraft continued on its way, returning data until October 1965, when the orientation of its antenna made communication with Earth impossible. However, scientists were able to re-establish contact with Mariner 4 in late 1967 and continued to receive data until December 20, 1967, when the mission was terminated. The spacecraft is now in a solar orbit.
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Mariner 3
Failed Mars flyby attempt (NASA)Launch: November 5, 1964
A shield that was designed to protect Mariner 3's instruments during launch failed to release once the spacecraft had reached Earth orbit. With its instruments covered and the extra weight of the shield dragging it down, the spacecraft was unable to obtain the necessary trajectory to send it on to Mars. The spacecraft is now in a solar orbit.
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Mars 1 (Sputnik 23)
Failed Mars flyby attempt (USSR)Launch: November 1, 1962
Mars 1 launched successfully and began the trip to Mars, returning data on interplanetary space. However, controllers lost contact with Mars 1 on March 21, 1963, when the spacecraft was 107 million kilometers (66 million miles) from Earth when signal was lost. The spacecraft is now in a solar orbit.
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Korabl 11 (Sputnik 22)
Failed Mars flyby attempt (USSR)Launch: October 24, 1962
Korabl 13 (Sputnik 24)
Failed Mars flyby attempt (USSR)Launch: November 4, 1962
Korabl 11 broke apart after reaching Earth orbit. The debris reentered Earth's atmosphere and was tracked by the U.S. Ballistic Missile Early Warning System in Alaska, who first thought it was a Soviet ICBM attack in response to the ongoing Cuban Missile Crisis. Korabl 13 broke apart in Earth orbit during a burn to transfer the probe to a Mars trajectory.
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Korabl 4 (Marsnik 1)
Failed Mars flyby attempt (USSR)Launch: October 10, 1960
Korabl 5 (Marsnik 2)
Failed Mars flyby attempt (USSR)Launch: October 14, 1960
Korabl 4 and 5 were the Soviet Union's first attempts at interplanetary probes. The third stage of both launch vehicles failed, and neither obtained Earth orbit.
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