Missions to Mars

Mars has historically been unfriendly to Earth’s attempts to visit it. More missions have been attempted to Mars than to any other place in the Solar System except the Moon, and about half of the attempts have failed. Some of these failures occurred because Mars was the first planet Earth attempted to explore, and the early exploration attempts taught us many lessons that have made subsequent missions more successful. But many failures have occurred relatively recently, proving again and again that space exploration is very, very difficult. But since 1996, Mars exploration has undergone a Renaissance, with data from four orbiters and four landed missions developing a revolutionary new view of Mars as an Earth-like world with a complex geologic history.
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
^ Back to top

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
^ Back to top

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
^ Back to top

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
^ Back to top

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
^ Back to top

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
^ Back to top

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.
^ Back to top

Yinghuo-1

Future Mars orbiter (China)
Launch: January 15, 2012, piggybacked on Phobos-Grunt
Yinghuo-1 crashed with Phobos-Grunt.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

Phobos 2

Mostly failed Mars orbiter & 2 Phobos landers
Launch: 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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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).
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.
^ Back to top

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.

Mars' Calendar

Time on Mars is easily divided into days based on its rotation rate and years based on its orbit. Sols, or Martian solar days, are only 39 minutes and 35 seconds longer than Earth days, and there are 668 sols (684 Earth days) in a Martian year.
For convenience, sols are divided into a 24-hour clock. Each landed Mars mission keeps track of "Local Solar Time," or LST, at its landing site, because Local Solar Time relates directly to the position of the Sun in the sky and thus the angle from which camera views are illuminated. The time of day, Local Solar Time, depends upon the lander's longitude on Mars.
Unlike on Earth, there is no leisurely-orbiting moon to give Mars "months," and while there have been many imaginative calendars suggested for Mars, none is in common use. The way that scientists mark the time of Mars year is to use solar longitude, abbreviated Ls (read "ell sub ess"). Ls is 0° at the vernal equinox (beginning of northern spring), 90° at summer solstice, 180° at autumnal equinox, and 270° at winter solstice.
On Earth, spring, summer, autumn, and winter are all similar in length, because Earth's orbit is nearly circular, so it moves at nearly constant speed around the Sun. By contrast, Mars' elliptical orbit makes its distance from the Sun change with time, and also makes it speed up and slow down in its orbit. Mars is at aphelion (its greatest distance from the Sun, 249 million kilometers, where it moves most slowly) at Ls = 70°, near the northern summer solstice, and at perihelion (least distance from the Sun, 207 million kilometers, where it moves fastest) at Ls = 250°, near the southern summer solstice. The Mars dust storm season begins just after perihelion at around Ls = 260°.
The coincidence of aphelion with northern summer solstice means that the climate in the northern hemisphere is more temperate than in the southern hemisphere.  In the south, summers are hot and quick, winters long and cold.
Ls marks the passage of time within a Mars year.  To count up the passage of time from one Mars year to the next, Mars scientists have settled upon the following convention:

For the purpose of this comparison, we use the solar longitude range 0°-360° to define a Mars year and adopt April 11, 1955 (Ls=0°) as the beginning of year 1. In this arbitrary convention, the Mariner 9, Viking, Phobos, and Pathfinder missions occurred in years 9-10, 12-15, 19-20, and 23, respectively. By comparison, the 1992-1999 [Earth-based] millimeter observations extend over years 21-24, and the 1997-1999 [Mars Global Surveyor] TES observations extend over years 23 and 24.

Tables of Seasonal Data for Mars

Martian years and start dates of northern hemisphere seasons
Mars year	Spring equinox (Ls = 0°)	Summer solstice (Ls = 90°)	Autumnal equinox (Ls = 180°)	Winter solstice (Ls = 270°)
01	Apr 11 1955	Oct 27 1955	Apr 27 1956	Sep 21 1956
02	Feb 26 1957	Sep 13 1957	Mar 15 1958	Aug 09 1958
03	Jan 14 1959	Aug 01 1959	Jan 31 1960	Jun 26 1960
04	Dec 01 1960	Jun 18 1961	Dec 18 1961	May 14 1962
05	Oct 19 1962	May 05 1963	Nov 05 1963	Mar 31 1964
06	Sep 05 1964	Mar 22 1965	Sep 22 1965	Feb 15 1966
07	Jul 24 1966	Feb 07 1967	Aug 10 1967	Jan 03 1968
08	Jun 10 1968	Dec 25 1968	Jun 27 1969	Nov 20 1969
09	Apr 28 1970	Nov 12 1970	May 15 1971	Oct 08 1971
10	Mar 15 1972	Sep 29 1972	Apr 01 1973	Aug 25 1973
11	Jan 31 1974	Aug 17 1974	Feb 17 1975	Jul 13 1975
12	Dec 19 1975	Jul 04 1976	Jan 04 1977	May 30 1977
13	Nov 05 1977	May 22 1978	Nov 22 1978	Apr 17 1979
14	Sep 23 1979	Apr 08 1980	Oct 09 1980	Mar 04 1981
15	Aug 10 1981	Feb 24 1982	Aug 27 1982	Jan 20 1983
16	Jun 28 1983	Jan 12 1984	Jul 14 1984	Dec 07 1984
17	May 15 1985	Nov 29 1985	Jun Jan 1986	Oct 25 1986
18	Apr 01 1987	Oct 17 1987	Apr 18 1988	Sep 11 1988
19	Feb 16 1989	Sep 03 1989	Mar 06 1990	Jul 30 1990
20	Jan 04 1991	Jul 22 1991	Jan 22 1992	Jun 16 1992
21	Nov 21 1992	Jun 08 1993	Dec 08 1993	May 04 1994
22	Oct 09 1994	Apr 26 1995	Oct 26 1995	Mar 21 1996
23	Aug 26 1996	Mar 13 1997	Sep 12 1997	Feb 06 1998
24	Jul 14 1998	Jan 29 1999	Jul 31 1999	Dec 25 1999
25	May 31 2000	Dec 16 2000	Jun 17 2001	Nov 11 2001
26	Apr 18 2002	Nov 03 2002	May 05 2003	Sep 29 2003
27	Mar 05 2004	Sep 20 2004	Mar 22 2005	Aug 16 2005
28	Jan 21 2006	Aug 08 2006	Feb 07 2007	Jul 04 2007
29	Dec 09 2007	Jun 25 2008	Dec 25 2008	May 21 2009
30	Oct 26 2009	May 13 2010	Nov 12 2010	Apr 08 2011
31	Sep 13 2011	Mar 30 2012	Sep 29 2012	Feb 23 2013
32	Jul 31 2013	Feb 15 2014	Aug 17 2014	Jan 11 2015
33	Jun 18 2015	Jan 03 2016	Jul 04 2016	Nov 28 2016
34	May 05 2017	Nov 20 2017	May 22 2018	Oct 16 2018
35	Mar 23 2019	Oct 08 2019	Apr 08 2020	Sep 02 2020
36	Feb 07 2021	Aug 25 2021	Feb 24 2022	Jul 21 2022
37	Dec 26 2022	Jul 12 2023	Jan 12 2024	Jun 07 2024
38	Nov 12 2024	May 29 2025	Nov 29 2025	Apr 25 2026
39	Sep 30 2026	Apr 16 2027	Oct 17 2027	Mar 12 2028
40	Aug 17 2028	Mar 03 2029	Sep 03 2029	Jan 28 2030

This table is taken from a 2010 paper by Bruce Cantor, Philip James, and Wendy Calvin: "MARCI and MOC observations of the atmosphere and surface cap in the north polar region of Mars," employing a convention described originally in a 2000 paper by Todd Clancy and several coauthors: "An intercomparison of ground-based millimeter, MGS TES, and Viking atmospheric temperature measurements: Seasonal and interannual variability of temperatures and dust loading in the global Mars atmosphere."
Here are how some major events in Mars exploration shake out, according to this calendar:

Martian Years and Seasons for Significant Mission Events
Earth Date	Mars year/Ls	Event
July 14, 1965	6.143	Mariner 4 flyby
August 1969	8.200	Mariner 6 and 7 flybys
November 1971	9.284	Mariner 9, Mars 2, and Mars 3 enter orbit
August 1972	10.64	Mars 2 and 3 shut down
October 27, 1972	10.102	Mariner 9 shuts down
February 1974	11.0	Mars 4 and 5 enter orbit
July 1976	12.88	Viking 1 Orbiter & Lander arrive
September 1976	12.116	Viking 2 Orbiter & Lander arrive
July 25, 1978	13.118	Viking 2 Orbiter shuts down
April 11, 1980	14.91	Viking 2 Lander shuts down
August 17, 1980	14.151	Viking 1 Orbiter shuts down
November 13, 1982	15.226	Viking 1 Lander shuts down
January 29, 1989	19.350	Phobos 2 enters orbit
March 27, 1989	20.18	Phobos 2 shuts down
July 4, 1997	23.142	Mars Pathfinder lands
September 1997	23.173	Mars Global Surveyor enters orbit; Mars Pathfinder shuts down
October 24, 2001	25.258	Mars Odyssey enters orbit
December 14, 2003	26.315	Nozomi flies past Mars
January 2004	26.325	Mars Express, Spirit, and Opportunity arrive
March 10, 2006	28.22	Mars Reconnaisance Orbiter arrives
November 5, 2006	28.130	Mars Global Surveyor shuts down
May 25, 2008	29.76	Phoenix lands
November 2, 2008	29.151	Phoenix shuts down
March 22, 2010	30.67	Last contact with Spirit
August 6, 2012	31.150	Curiosity lands

Missions to Venus and Mercury

Active missions

MESSENGER

Launch: 3 Aug 2004. Venus flyby 1: 24 Oct 2006. Venus flyby 2: 5 Jun 2007. Mercury flyby 1: 14 Jan 2008. Mercury flyby 2: 6 Oct 2008. Mercury flyby 3: 29 Sep 2009. Mercury orbit insertion: 17 Mar 2011. Ongoing.
Links: Blog posts about MESSENGER - JHUAPL - NASA - KSC - NSSDC - Wikipedia

Venus Express

Launch: 11 Nov 2005. Orbit insertion: 11 Apr 2006.
Links: Blog posts about Venus Express - ESA public - ESA science - NSSDC - Wikipedia

Past missions

Cassini-Huygens

Successful Saturn orbiter (NASA)
Launch: Oct. 15, 1997
Venus flyby 1: April 26, 1998
Venus flyby 2: June 24, 1999
Cassini-Huygens used the planet Venus for two gravity assists, leading up to Earth and Jupiter flybys and its eventual arrival at Saturn.  The flybys were notable for the failure to detect lightning at Venus. Go to the main Cassini-Huygens entry for information on its mission to Saturn.

Magellan

Successful Venus orbiter (NASA)
Launch: May 4, 1989
Venus orbit insertion: August 10, 1990
By the end of its mission, Magellan had mapped over 98% of Venus at a resolution of 100 meters or better using Synthetic Aperture Radar (SAR).  Images were acquired over three “cycles” at different geometries, permitting stereoscopic views of parts of the surface.  Magellan also acquired topography, slope, radiometry, and scatterometry measurements of the surface over a mission spanning five years.

Magellan Timeline
04 May 1989	Launch
10 Aug 1990	Venus orbit insertion and spacecraft checkout
15 Sep 1990	Cycle 1:  Radar mapping (left-looking)
15 May 1991	Cycle 2:  Radar mapping (right-looking)
15 Jan 1992	Cycle 3:  Radar mapping (left-looking)
14 Sep 1992	Cycle 4:  Gravity data acquisition
24 May 1993	Aerobraking to circular orbit
03 Aug 1993	Cycle 5: Gravity data acquisition
30 Aug 1994	Windmill experiment
12 Oct 1994	Termination experiment - loss of signal
13 Oct 1994	Presumed loss of spacecraft

Galileo

Successful Jupiter orbiter (NASA)
Launch: October 18, 1989
Venus flyby: February 10, 1990
Galileo flew by Venus on the way to Jupiter, collecting measurements of charged particles, dust and magnetism, infrared and ultraviolet spectral observations, data for infrared lower-atmosphere maps, and 81 camera images. The data were mostly not played back until November, 1990. Go to the main Galileo entry for information on Galileo's mission to Jupiter.

Vega 2

Successful Venus probe and Comet Halley flyby (USSR)
Launch: December 21, 1984
Venus flyby and gravity assist: June 15, 1985
Vega 2 was identical to Vega 1.

Vega 1

Successful Venus probe and Comet Halley flyby (USSR)
Launch: December 15, 1984
Venus flyby and gravity assist: June 11, 1985
As Vega 1 swung by Venus, it deployed a 2.4-meter probe into the atmosphere. The probe deployed a balloon almost immediately upon entering the atmosphere. The balloon, which measured temperature, pressure, wind velocity and visibility of the atmosphere, covered 9,000 kilometers in 47 hours before it burst. The probe took readings of the atmosphere as it descended to the surface.

Venera 16

Successful Venus orbiter (USSR)
Launch: June 7, 1983
Venus arrival: October 10, 1983
Venera 15 and 16 created a radar map of Venus over a joint mission lasting 8 months.

Venera 15

Successful Venus orbiter (USSR)
Launch: June 2, 1983
Venus arrival: October 10, 1983
Venera 15 and 16 created a radar map of Venus over a joint mission lasting 8 months.

Venera 14

Successful Venus orbiter and lander (USSR)
Launch: November 4, 1981
Venus arrival: March 5, 1982
Venera 14 sent back images of the surface and a mechanical arm collected a sample for testing. The spacecraft survived for 57 minutes before succumbing to the heat and extreme pressure.

Venera 13

Successful Venus orbiter and lander (USSR)
Launch: October 30, 1981
Venus arrival: March 1, 1982
Venera 13 returned the first color images from the surface of Venus, landing at 7.5° S, 303° E.  A drilling arm collected a sample that was examined by an onboard x-ray fluorescence spectrometer to determine its composition. The lander survived 127 minutes before giving in to the extreme heat (457°C) and the tremendous pressure (84 times the pressure at sea level on Earth).

Venera 11

Successful Venus orbiter and lander (USSR)
Launch: September 9, 1978
Venus arrival: December 25, 1978
Details about Venera 11 are sketchy; however, the spacecraft did make a soft landing on the surface, and sent back evidence of thunder and lightning as well as the presence of carbon monoxide in the lower altitudes. Data was transmitted back to Earth for 95 minutes before the lander rotated out of range of the orbiting relay.

Venera 12

Successful Venus orbiter and lander (USSR)
Launch: September 14, 1978
Venus arrival: December 21, 1978
Launched three days after Venera 11, Venera 12 actually made it to Venus four days before the other spacecraft. Venera 12 was designed to study the atmospheric composition and clouds of Venus. The lander transmitted 110 minutes of data before the planet rotated out of range of the orbiting relay.

Pioneer Venus 2 (Pioneer Venus Multiprobe)

Four successful Venus probes (NASA)
Launch: August 8, 1978
Venus arrival: December 9, 1978
Pioneer Venus 2 consisted of four separate atmospheric probes; one large probe 1.5 meters in diameter, which deployed a parachute to slow its descent, and three small probes (0.8 meters across) which plunged straight through the atmosphere.  The large probe was released from the spacecraft bus on November 16, 1978. The three smaller probes were released four days later. All of the probes arrived at Venus on December 9, 1978. Each probe took atmospheric measurements as they descended through the cloud layer. One of the probes survived to transmit data for over an hour after it impacted with the surface. The spacecraft bus that carried the probes also had instruments and made measurements in Venus’ uppermost atmosphere before burning up.

Pioneer Venus 1 (Pioneer Venus Orbiter)

Successful Venus orbiter (NASA)
Launch: May 20, 1978
Venus orbit insertion: December 4, 1978
Pioneer Venus 1 carried 17 experiments, including a radar mapper. Scientists used the radar to map nearly the entire planet, resolving features as small as 80 kilometers. The spacecraft remained in orbit until August of 1992, when it used up all its fuel and burnt up in the atmosphere.

Venera 10

Successful Venus orbiter and lander (USSR)
Launch: June 14, 1975
Venus landing: October 25, 1975
The Venera 10 spacecraft separated into two different sections, an orbiter and a lander, on October 23, 1975. Two days later, the lander touched down on the surface of Venus 2,200 kilometers from the Venera 9 lander, somewhere within a 150 km radius of 15.42° N, 291.51° E. With the orbiter acting as a relay, the lander transmitted images from the surface as well as data about clouds and the surface environment.

Venera 9

Successful Venus orbiter and lander (USSR)
Launch: June 8, 1975
Venus landing: October 22, 1975
The Venera 9 lander separated from the orbiter on October 20, 1975. Two days later, the lander touched down and became the first spacecraft to transmit a picture from the surface of another planet. It landed within a 150-kilometer radius of 31.01° N, 291.64° E.  In addition, the lander sent back information on the Venusian clouds, atmospheric composition, and light levels. All of the information was transmitted from the surface to the orbiter, which then relayed the signal to Earth. Besides acting as a data relay, the orbiter also studied the cloud structure of the planet.

Mariner 10

Successful Mercury multiple flyby (NASA)
Launch: November 3, 1973
Venus flyby and gravity assist: February 5, 1974
Mariner 10 flew by Venus for a gravity assist on its way to Mercury. It flew within 4,200 kilometers (2,600 miles) of Venus and took the first ultraviolet images of the planet.

Cosmos 482

Failed Venus lander attempt (USSR)
Launch: March 31, 1972
The final stage of the rocket carrying the spacecraft into orbit failed and it was unable to achieve the necessary trajectory to carry it on to Venus.

Venera 8

Successful Venus lander (USSR)
Launch: March 27, 1972
Venus landing: July 22, 1972
Upon Venus arrival Venera 8 used aerobraking to decelerate, and then deployed a parachute. A refrigeration unit cooled the spacecraft's components, protecting them from the intense heat as the lander descended to the surface. Once on the ground, the spacecraft transmitted data for 50 minutes, confirming a very high surface temperature and crushing atmospheric pressure.  It also measured the light level on Venus’ surface and found it suitable for surface photography, setting the stage for the images to be returned by Venera 9, 10, 13, and 14.

Cosmos 359

Failed Venus lander attempt (USSR)
Launch: August 22, 1970
The final stage of the rocket carrying the spacecraft into orbit failed and it was unable to achieve the necessary trajectory to carry it on to Venus.

Venera 7

Successful Venus probe (USSR)
Launch: August 17, 1970
Venus arrival: December 15, 1970
When Venera 7 arrived it deployed a parachute and began its descent to the surface. Scheduled to take 60 minutes to descend, the probe touched down in only 35 minutes, possibly because its parachute may have been damaged by high winds. The spacecraft then transmitted a weak signal for 23 minutes, becoming the first spacecraft to return data from the surface of another planet. It reported surface temperatures of 475°C and atmospheric pressures 90 times greater than Earth's.

Venera 6

Successful Venus probe (USSR)
Launch: January 10, 1969
Venus arrival: May 17, 1969
Twin to Venera 5, Venera 6 arrived just a day after its sister ship. Once at Venus, the spacecraft deployed a parachute and descended through the atmosphere. Scientists on Earth received 51 minutes of data as the probe descended 38 kilometers (almost 24 miles). The spacecraft was damaged the crushing pressure before it reached the surface.

Cosmos 167

Failed Venus probe attempt (USSR)
Launch: June 17, 1967
The final stage of the rocket carrying the spacecraft into orbit failed and it was unable to achieve the necessary trajectory to carry it on to Venus.

Mariner 5

Successful Venus flyby (NASA)
Launch: June 14, 1967
Venus flyby: October 19, 1967
Mariner 5 flew within 4,000 kilometers (2,400 miles) of the Venusian cloud tops. During its flyby, the spacecraft measured a surface temperature of 267°C.

Venera 4

Successful Venus probe (USSR)
Launch: June 12, 1967
Venus arrival: October 18, 1967
When Venera 4 arrived at Venus it dropped several instruments, including a thermometer and a barometer, into the atmosphere. It received data back from these probes before it deployed a parachute and descended into the atmosphere itself. Preliminary readings seemed to indicate that the probe had taken measurements all the way down to the surface, but later analysis suggested that the crushing atmosphere damaged the spacecraft at an altitude of almost 25 kilometers. The probe revealed an atmosphere made almost entirely of carbon dioxide, with temperatures ranging from 40°C high up in the atmosphere to 280°C closer to the surface, and pressures ranging from 15 to 22 atmospheres.

Venera 3

Venus probe attempt (USSR)
Launch: Nov. 16, 1965
Venus impact: March 1, 1966
Venera 3 was the first spacecraft to land on (impact) another planet, but no data was returned. It is believed that Venus's thick atmosphere and crushing pressure destroyed the spacecraft on its way to the surface.

Venera 2

Venus flyby attempt (USSR)
Launch: Nov. 12, 1965
Venera 2 flew within 24,000 kilometers of Venus on February 27, 1966, but communications with the spacecraft was lost just before its close approach with the planet.

Zond 1

Failed Venus probe attempt (USSR)
Launch: April 2, 1964
Communications with the spacecraft was lost while on its way to Venus.

Cosmos 27

Failed Venus flyby attempt (USSR)
Launch: March 27, 1964
The final stage of the rocket carrying the spacecraft into orbit failed and it was unable to achieve the necessary trajectory to carry it on to Venus.

Venera 1964B

Failed Venus flyby attempt (USSR)
Launch: Mar. 1, 1964
The rocket carrying the spacecraft failed to reach Earth orbit.

Venera 1964A

Failed Venus flyby attempt (USSR)
Launch: February 19, 1964
The rocket carrying the spacecraft failed to reach Earth orbit.

Sputnik 21

Failed Venus probe attempt (USSR)
Launch: September 12, 1962
The 3rd stage of the rocket exploded shortly after liftoff, destroying the spacecraft.

Sputnik 20

Failed Venus probe attempt (USSR)
Launch: September 1, 1962
The rocket's final stage failed and the spacecraft was unable to achieve to escape Earth orbit.

Mariner 2

Successful Venus flyby (NASA)
Launch: August 27, 1962
Venus flyby: December 14, 1962
Mariner 2 was the first spacecraft to successfully fly by Venus, at an altitude of 34,773 kilometers. The spacecraft discovered ground temperatures as high as 428°C (800°F). Other instruments detected no water vapor in the atmosphere or any evidence of a magnetic field around the planet. Radio contact was lost on January 3, 1963.

Sputnik 19

Failed Venus probe attempt (USSR)
Launch: August 25, 1962
The spacecraft made it into Earth orbit, but the rocket's last stage failed and Sputnik 19 was unable to achieve its Venus trajectory. It re-entered Earth's atmosphere three days later.

Mariner 1

Failed Venus flyby attempt (NASA)
Launch: July 22, 1962
Shortly after launch, the rocket veered off course and was destroyed by ground controllers.

Venera 1

Failed Venus probe attempt (USSR)
Launch: February 12, 1961
Communications with the spacecraft was lost while Venera 1 was on its way to Venus.

Sputnik 7

Failed Venus probe attempt (USSR)
Launch: February 4, 1961
The final stage of the rocket carrying Sputnik 7 into orbit failed and the spacecraft was unable to achieve the necessary trajectory to carry it on to Venus.

International Space Station Dashboard

Number of humans currently in space: 6

Current Expedition: 41 (September—November 2014)

 

 

Crew 1: Soyuz TMA-13M

Launched: May 28, 2014
Landing: November 10, 2014

Maxim Suraev

Commander, Roscosmos
Previous spaceflight experience: Expedition 21/22 (2009-2010)
NASA biography

Alexander Gerst

Flight Engineer, European Space Agency
Previous spaceflight experience: rookie
ESA biography | NASA interview | Twitter

Reid Wiseman

Flight Engineer, NASA
Previous spaceflight experience: rookie
NASA biography | NASA interview | Twitter

---

Back to top ^

Crew 2: Soyuz TMA-14M

Launched: September 26, 2014
Landing: March 2015

Alexander Samokutyaev

Flight Engineer, Roscosmos
Previous spaceflight experience: Expedition 27/28 (2011)
NASA biography | NASA interview | NASA video profile

Elena Serova

Flight Engineer, Roscosmos
Previous spaceflight experience: rookie
NASA biography | NASA interview | NASA video profile

Barry Wilmore

Flight Engineer, NASA
Previous spaceflight experience: STS-129 (2009)
NASA biography | NASA interview | NASA video profile

---

Back to top ^

Currently docked/berthed cargo vehicles

Roscosmos

Progress M-24M
Arrived: May 29, 2014
Departure: November 10, 2014
NASA overview

European Space Agency

Automated Transfer Vehicle (ATV-5)
Arrived: July 24, 2014
Departure: October 27, 2014
ATV website

SpaceX

Dragon CRS-4
Arrived: Sept. 23, 2014
Departure: October 2014
Dragon website

---

Back to top ^

Upcoming cargo missions

Orbital Sciences Corporation

ORB-3 Cygnus
No earlier than Oct. 14, 2014
Cygnus fact sheet (PDF)

Roscosmos

Progress M-25M
Oct. 29, 2014
NASA overview

SpaceX

Dragon CRS-5
Dec. 1, 2014
Dragon website

HUBBLE SPACE TELESCOPE

Donald Savage
Headquarters, Washington, DC              April 24, 1995
(Phone:  202/358-1547)

Tammy Jones
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-5566)

Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone:  410/338-4514)


RELEASE:  95-56


FIFTH ANNIVERSARY OF HUBBLE LAUNCH OBSERVED TODAY

       Today is the fifth anniversary of the launch of 
NASA's Hubble Space Telescope.  Celebrated throughout the 
world as the finest astronomical instrument ever built, 
Hubble has provided remarkable new views of the universe 
which have revolutionized astronomers' thinking about a 
variety of current astronomical mysteries.  

       "The Hubble Space Telescope is truly a national 
scientific treasure," said Dr. Wesley Huntress, Jr., NASA's 
Associate Administrator for Space Science.  "With a rate of 
discovery that is unprecedented for any modern observatory, 
Hubble not only has revolutionized astronomy, it has 
engaged the interest and imagination of the public more 
than any space science satellite has done before.

       "And that may be its most far-reaching and important 
legacy -- getting a new generation of young people excited 
about science," Huntress said.

Launch and First Three Years

       Launched April 24, 1990, on the Space Shuttle 
Discovery's STS-31 mission, the Hubble Space Telescope, 
with a resolving power calculated to be ten times better 
than any telescope on Earth, was poised to open a new era 
in astronomy.  Within a few months, however, a flaw was 
discovered in Hubble's main mirror which significantly 
reduced the telescope's ability to focus.

       The focusing defect was due to spherical aberration, 
an optical distortion caused by an incorrectly shaped 
mirror.  Instead of being focused into a sharp point, light 
collected by the mirror was spread over a larger area in a 
fuzzy halo.  Images of objects such as stars, planets and 
galaxies were blurred.  However, on relatively bright 
objects, Hubble's cameras were still able to provide images 
far superior to any telescope on the ground.  

       Program and project management officials, working 
with the scientific community, developed a plan to take 
advantage of the telescope's instruments that were not 
affected by the aberration, such as ultraviolet and 
spectrographic observations.

       During its first three years of operation, Hubble 
provided significant new information and discoveries about 
the universe, including astonishing images of supernova 
1987A and a disk of cold gas fueling a black hole.

       The team also began developing a corrective optics 
package that, together with a new camera already scheduled 
for installation in Hubble in 1993, would restore Hubble to 
its intended imaging capabilities.  

       The two major instruments planned for installation, 
the Wide Field/Planetary Camera (WF/PC-II) and the 
Corrective Optics Space Telescope Axial Replacement 
(COSTAR), were designed to correct the aberration.  WF/PC-
II was designed so that the light reaching each of the 
instrument's four cameras was corrected by relay mirrors 
polished to a prescription compensating for the incorrect 
figure produced by Hubble's primary mirror.  

       COSTAR routed properly focused light to three of 
Hubble's five instruments.  Ball Corp. built Hubble's 
corrective optics for the Goddard Space Flight Center, 
Greenbelt, MD.

       The seven astronauts selected to service Hubble 
practiced for nearly a year-and-a-half.  They spent 
hundreds of hours practicing and learning the uses of more 
than 100 different servicing tools.  This mission would be 
one of the most challenging missions NASA had ever 
attempted.  

Servicing Mission Opens New Era

       On December 2, 1993, the STS-61 crew launched on 
Space Shuttle Endeavour for an 11-day mission with a record 
five spacewalks planned.  Watched by millions worldwide on 
live television, the astronauts endured long hours of 
challenging spacewalks to install instruments containing 
the corrective optics and replaced the telescope's solar 
arrays, gyroscopes, and other electronic components.  

       They installed WF/PC-II and replaced the High Speed 
Photometer with the COSTAR instrument.  They also installed 
a new computer co-processor to upgrade the telescope's 
computer memory and processing speed, the Solar Array Drive 
Electronics unit and the Goddard High Resolution 
Spectrograph Redundancy Kit.  

       The crew completed everything it set out to do and 
the mission was declared a success.  After five weeks of 
engineering check-out, optical alignment and instrument 
calibration, the confirmation of success came as the first 
images were received on the ground from the space 
telescope.  

     NASA Administrator Daniel Goldin was joined in 
announcing the successes by Dr. John Gibbons, Assistant to 
the President for Science and Technology, and Sen. Barbara 
Mikulski (D-MD), at a press conference at Goddard.  

       "This is phase two of a fabulous, two-part success 
story," Goldin said at the press conference.  "The world 
watched in wonder last month as the astronauts performed an 
unprecedented and incredibly smooth series of space walks.  
Now, we see the real fruits of their work and that of the 
entire NASA team."

       Not only has Hubble advanced science's understanding 
of the universe, it also is making direct contributions 
through a variety of technological spinoffs.  During 1994 a 
new, non-surgical breast biopsy technique was developed 
using imaging Charge Coupled Devices, originally developed 
for Hubble's Imaging Spectrograph.  This technology now 
enables doctors to precisely locate a suspicious lump in a 
woman's breast and use a needle, instead of a scalpel, to 
extract a sample of tissue for study. 

Looking Ahead

       The Hubble Space Telescope was designed to work on 
orbit for 15 years, providing an unparalleled observatory 
for astronomers well into the next century.  To keep Hubble 
running smoothly, three additional servicing missions are 
planned, similar to but probably not as extensive as the 
first servicing mission in 1993.

       During the next servicing mission, scheduled for 
February 1997, astronauts will install two new instruments 
-- the Space Telescope Imaging Spectrograph and the Near 
Infrared Camera and Multi-Object Spectrograph.  The third 
servicing mission, scheduled for November 1999, will see 
the installation of the Hubble Advanced Camera for 
Exploration, which will greatly enhance the telescope's 
imaging capabilities.

Hubble's Ten Most Important Scientific Discoveries 

       Hubble program and project scientists selected the 
following "top ten" list of discoveries from hundreds of 
findings made over the past five years by scientists using 
Hubble.  The selections were based on their scientific 
merit and long-term importance in advancing the field of 
astronomy.  Since it became operational in 1990, NASA's 
Hubble Space Telescope:

  *  Offered the first conclusive evidence for the 
existence of immense black holes, millions or billions of 
times the mass of Earth's Sun. 

  *  Showed that the universe might be much younger than 
had been previously thought.  This was accomplished by 
calculating the universe's expansion rate based on an 
accurate Hubble distance measurement to a remote galaxy.

  *  Gave the first direct visual evidence that the 
universe is evolving as predicted in Big Bang cosmology, by 
resolving the shapes of the farthest galaxies ever seen. 

  *  Discovered that quasars, very distant and remarkably 
bright objects, are even more mysterious than commonly 
thought because many do not dwell in the cores of galaxies, 
but are isolated in space.

  *  Suggested that dark matter in the universe is more 
exotic than previously thought, by finding that nature 
doesn't make enough of the extremely small Red Dwarf stars 
that were once a leading candidate for the universe's 
"missing mass."

  *  Supported the Big Bang theory by refining estimates of 
the amount of deuterium in space, an element created in the 
initial cosmic fireball that gave birth to the universe.

  *  Solved the mystery of intergalactic clouds of hydrogen 
by showing that they are really gigantic halos of galaxies.

  *  Implied that planets, and presumably life, might be 
abundant in the universe by discovering disks of dust that 
might be embryonic planetary systems around young stars. 

  *  Provided important details and surprising findings of 
the spectacular collisions of comet Shoemaker-Levy 9 with 
Jupiter last year.  

  *  Revealed dynamic weather changes on nearly all the 
planets with a clarity once attainable only with spacecraft 
flybys.  Scientists found that most planets' atmospheres 
are much more active than previously believed, and the 
ability of Hubble to 'revisit' the planets allows frequent 
monitoring similar to Earth weather satellites.

A Photo Gallery Of The Universe:  The Best Of 
Hubble Images 1990-1995

       Hubble Space Telescope's dramatic images evoke a 
sense of awe and wonder.  The following is a selection of 
Hubble's ten most spectacular and important images, 
selected on the basis of scientific value as well as 
aesthetic content.

       The images are available in color or B&W prints or 
via the Internet in a special Hubble 5th Anniversary Home 
Page.  See Editor's Note following this release for 
information on obtaining images or accessing the home page.  

SUPERNOVA 1987A - HALO FOR A VANISHED STAR
       An eerie, nearly mirror-image pair of red 
luminescent gas "hula-hoops" framing the expanding debris 
of a star was seen as a supernova explosion in 1987.  April 
1994.
NASA photo number:   94-HC-39

THE ORION NEBULA - STELLAR BIRTHPLACE
       An immense wall of glowing gases forms a colorful 
backdrop to dozens of newborn stars, many of which have 
dust disks -- as revealed by Hubble -- that might be 
embryonic solar systems.  January 1994.
NASA photo number:   94-HC-163

THE RING GALAXY - RESULT OF A BULL'S-EYE COLLISION
       A spectacular head-on collision between a spiral 
galaxy and a smaller intruder sends out a ripple of energy 
that triggers a firestorm of new star birth, forms a 
dazzling ring-like structure.  January 1995.
NASA photo number:  95-HC-23 

COMET P/SHOEMAKER-LEVY 9 BOMBARDS JUPITER
       Hubble followed unexpected and dramatic changes in 
Jupiter's atmosphere caused by collisions with comet 
fragments.  The titanic blasts left Jupiter with a 
temporary "bruised" appearance, caused by black debris that 
was tossed high above the giant planet's cloud tops.  July 
1994.
NASA photo number:  94-HC-188

SPIRAL GALAXY M100
       A majestic pinwheel formed by hundreds of billions 
of stars harbors rare pulsating stars that can yield clues 
to the size and age of the universe.  The galaxy is so far 
away, Hubble sees it as it appeared at about the time 
dinosaurs roamed the Earth.  January 1994.
NASA photo number:  94-HC-280

SATURN STORM
       A rare storm, large enough to swallow Earth, appears 
near Saturn's equator.  High altitude winds give the storm 
a distinctive arrowhead shape. 
January 1994.
NASA photo number:  94-HC-556

RING AROUND A SUSPECTED BLACK HOLE IN GALAXY NGC 
4261
       The gravitational pull of a suspected super-massive 
black hole forms a Frisbee-like disk of cool gas, at the 
core of an energetic galaxy.  Subsequent Hubble 
observations of yet another active galaxy confirmed the 
reality of monstrous black holes -- gravitational "sink 
holes" that trap everything, even light.  November 1992. 
NASA photo number:  92-HC-708

PLANETARY NEBULA NGC 6543, GASEOUS COCOON AROUND A 
DYING STAR
       Mysterious stellar fireworks create expanding gas 
shells and blowtorch-like jets which form a spectacularly 
intricate and symmetrical structure.  The nebula is a 
fossil record of the late stages of the star's evolution.  
January 1995.
NASA photo number:  95-HC-24

CYGNUS LOOP - BLAST WAVE FROM A STELLAR TIME-BOMB
       High speed gas from a supernova explosion slams into 
dark cooler clouds of interstellar material.  Shocked and 
heated by this tidal wave of energy, the clouds glow in 
bright, neon-like colors.  February 1995.
NASA photo number:  95-HC-77

WEATHER FORECAST FOR MARS 
       Wispy clouds, a melting polar ice cap, and a dust-
storm free surface all indicate a cool, clear spring time 
in the Martian northern hemisphere.  Hubble also is serving 
as a weather satellite for studying the climate on other 
planets.  February 1995.
NASA photo number:  95-HC-115

       The Space Telescope Science Institute is operated by 
AURA (the Association of Universities for Research in 
Astronomy, Inc.) for NASA, under contract with the Goddard 
Space Flight Center, Greenbelt, MD.  The Hubble Space 
Telescope is a project of international cooperation between 
NASA and the European Space Agency.

   - end -

EDITOR'S NOTE:   The HST Top Ten Images are available to 
news media representatives by calling the Headquarters 
Broadcast & Imaging Branch at 202/358-1900, the Goddard 
Space Flight Center at 301/286-8956 or 286-7277, or the 
Space Telescope Science Institute at 410/338-4562 (use the 
NASA photo number listed for each image).  


       The "Top Ten Images" also are available via the 
Internet in a special Hubble 5th Anniversary Home Page in 
GIF, JPEG and TIFF formats.  Users can access this page 
using the following protocol:

  *  Anonymous ftp to ftp.stsci.edu:

GIF files are in /pubinfo/gif, with extension ".gif"
JPEG files are in /pubinfo/jpeg, with extension ".jpg"
TIFF files are in /pubinfo/tiff, with extension ".tif"

  *  WWW -- follow links in http://www.stsci.edu/pubinfo/BestOfHST95.html

 or browse directories using 

http://www.stsci.edu/ftp/pubinfo and links to gif, jpeg and tiff

NASA press releases and other information are available 
automatically by sending an Internet electronic mail 
message to domo@hq.nasa.gov.  In the body of the message 
(not the subject line) users should type the words 
"subscribe press-release" (no quotes).  The system will 
reply with a confirmation via E-mail of each subscription.  
A second automatic message will include additional 
information on the service.  Questions should be directed 
to (202) 358-4043.