Mars - Missions To Mars

After the Moon the planet Mars was the destination of choice during the early days of space travel. The Soviet Union was particularly eager to reach the Red Planet before the United States. A historical log of all Mars missions is presented in Table 7.1.

Many Failures

Historically, spacecraft have had a difficult time making it to Mars in working order and staying that way. As shown in Table 7.1, more than half of the missions intended for Mars have failed for one reason or another. Some were plagued by launch problems, while others suffered malfunctions during flight, descent, or landing.

Mars missions undertaken during the 1960s by the former Soviet Union were particularly trouble-prone. All six of them failed. Although the next decade showed some improvement, little usable data were obtained from the spacecraft that reached their destination. The one attempt to reach Mars by the Russian space agency, in 1996, failed when the spacecraft was unable to leave Earth orbit.

In contrast to the Soviet Union's Mars attempts, most NASA Mars missions conducted during the 1960s achieved their objectives. There was also notable success over the next decade with the Viking spacecraft. There was a long lull after that in NASA's Mars exploration program.

During the 1990s NASA launched five separate missions to Mars. Their names were Mars Observer (1992), Mars Global Surveyor (1996), Mars Pathfinder (1996), Mars Climate Orbiter (1998), and Mars Polar Lander (1999). Only two of the missions were successful (Mars Global Surveyor and Mars Pathfinder). The other spacecraft were lost on arrival.

NASA lost contact with the Mars Observer just before it was to go into orbit around Mars. It is believed that some kind of fuel explosion destroyed the spacecraft as it began its maneuvering sequence. The Observer carried a highly sophisticated gamma-ray spectrometer designed to map the Martian surface composition from orbit. Failure of the mission resulted in a loss estimated at $1 billion. This was by far the most expensive of NASA's failed Mars missions.

In June 1999 the Mars Climate Orbiter was more than sixty miles off-course when it ran into the Martian atmosphere and was destroyed. The loss of the $85 million spacecraft was particularly embarrassing for NASA, because it was due to human error. An investigation revealed that flight controllers had made mistakes doing unit conversions between metric units and English system units. This resulted in erroneous steering commands being sent to the spacecraft. Outside investigators complained that the problem was larger than some mathematical errors. They blamed overconfidence and poor oversight by NASA management during the mission.

NASA's embarrassment deepened a few months later when the Mars Polar Lander was lost. The loss was attributed to a software problem that caused the spacecraft to think it had touched down on the surface even though it had not. The computer apparently shut down the engines during descent and let the spacecraft plummet TABLE 7.1 Historical log of Mars expeditions, 1960–2005 Adapted from "Historical Log," in NASA's Mars Exploration Program, National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, October 13, 2005, http://marsprogram.jpl.nasa.gov/missions/log/ (accessed January 31, 2006)at high speed into the ground, where it was destroyed. The cost of the failed spacecraft was estimated at $120 million.

TABLE 7.1
Historical log of Mars expeditions, 1960–2005
Mission	Country	Launch date	Purpose	Results
SOURCE: Adapted from "Historical Log," in NASA's Mars Exploration Program, National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, October 13, 2005, http://marsprogram.jpl.nasa.gov/missions/log/ (accessed January 31, 2006)
[Unnamed]	USSR	10/10/1960	Mars flyby	Did not reach Earth orbit
[Unnamed]	USSR	10/14/1960	Mars flyby	Did not reach Earth orbit
[Unnamed]	USSR	10/24/1962	Mars flyby	Achieved Earth orbit only
Mars 1	USSR	11/1/1962	Mars flyby	Radio failed at 65.9 million miles (106 million km)
[Unnamed]	USSR	11/4/1962	Mars flyby	Achieved Earth orbit only
Mariner 3	U.S.	11/5/1964	Mars flyby	Shroud failed to jettison
Mariner 4	U.S.	11/28/1964	First successful Mars flyby 7/14/65	Returned 21 photos
Zond 2	USSR	11/30/1964	Mars flyby	Passed Mars but radio failed, returned no planetary data
Mariner 6	U.S.	2/24/1969	Mars flyby 7/31/69	Returned 75 photos
Mariner 7	U.S.	3/27/1969	Mars flyby 8/5/69	Returned 126 photos
Mariner 8	U.S.	5/8/1971	Mars orbiter	Failed during launch
Kosmos 419	USSR	5/10/1971	Mars lander	Achieved Earth orbit only
Mars 2	USSR	5/19/1971	Mars orbiter/lander arrived 11/27/71	No useful data, lander destroyed
Mars 3	USSR	5/28/1971	Mars orbiter/lander, arrived 12/3/71	Some data and few photos
Mariner 9	U.S.	5/30/1971	Mars orbiter, in orbit 11/13/71 to 10/27/72	Returned 7,329 photos
Mars 4	USSR	7/21/1973	Failed Mars orbiter	Flew past Mars 2/10/74
Mars 5	USSR	7/25/1973	Mars orbiter, arrived 2/12/74	Lasted a few days
Mars 6	USSR	8/5/1973	Mars orbiter/lander, arrived 3/12/74	Little data return
Mars 7	USSR	8/9/1973	Mars orbiter/lander, arrived 3/9/74	Little data return
Viking 1	U.S.	8/20/1975	Mars orbiter/lander, orbitb 6/19/76–1980, lander 7/20/76–1982	Combined, the Viking orbiters and landers returned 50,000+ photos
Viking 2	U.S.	9/9/1975	Mars orbiter/lander, orbit 8/7/76–1987, lander 9/3/76–1980	Combined, the Viking orbiters and landers returned 50,000+ photos
Phobos 1	USSR	7/7/1988	Mars/Phobos orbiter/lander	Lost 8/88 en route to Mars
Phobos 2	USSR	7/12/1988	Mars/Phobos orbiter/lander	Lost 3/89 near Phobos
Mars Observer	U.S.	9/25/1992	Orbiter	Lost just before Mars arrival 8/21/93
Mars Global Surveyor	U.S.	11/7/1996	Orbiter, arrived 9/12/97	Currently conducting prime mission of science mapping
Mars 96	Russia	11/16/1996	Orbiter and landers	Launch vehicle failed
Mars Pathfinder	U.S.	12/4/1996	Mars lander and rover, landed 7/4/97	Last transmission 9/27/97
Nozomi (Planet-B)	Japan	7/4/1998	Mars orbiter	Could not achieve Martian orbit due to propulsion problem
Mars Climate Orbiter	U.S.	12/11/1998	Orbiter	Lost on arrival at Mars 9/23/99
Mars Polar Lander/Deep Space 2	U.S.	1/3/1999	Lander/descent probes to explore Martian South Pole	Lost on arrival 12/3/99
Mars Odyssey	U.S.	4/7/2001	Orbiter	Currently conducting prime mission of science mapping
Mars Express	Europe	6/2/2003	Orbiter and Beagle 2 Lander	Orbiter currently collecting planetary data. Beagle 2 lost during descent.
Mars Exploration	U.S.	6/10/03 (Spirit) and 7/7/03 (Opportunity)	Two rovers: Spirit and Opportunity	Rovers landed in January 2004. Currently exploring planet surface.
Mars Reconnaissance Orbiter	U.S.	8/12/2005	Orbiter	Scheduled to arrive in March 2006