MESUR (Mars Environmental SURvey) was a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

program designed to explore

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

in preparation for human follow-up missions of the

Space Exploration Initiative The Space Exploration Initiative was a 1989–1993 space public policy initiative of the George H. W. Bush administration. On July 20, 1989, the 20th anniversary of the Apollo 11 Moon landing, US President George H. W. Bush announced plans for ...

. The only mission of the program that was completed was '' MESUR Pathfinder''.

History

MESUR was a planned set of 16 surface missions on Mars that would also set up a planetary network across Mars and work in conjunction with ''

Mars Observer The ''Mars Observer'' spacecraft, also known as the ''Mars Geoscience/Climatology Orbiter'', was a Robotic spacecraft, robotic space probe launched by NASA on September 25, 1992, to study the Martian surface, atmosphere, climate and magnetic fie ...

''. The original plan was proposed by

NASA Ames The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laborat ...

, but it would eventually include ideas from the competing

JPL The Jet Propulsion Laboratory (JPL) is a federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by California Institute of Technology (Caltech) researche ...

proposal. It was envisioned as a low-cost method of surveying Mars, with risk tolerance, since a loss of a spacecraft was not fatal to the program, because of multiple relatively cheap space probes. ''MESUR Pathfinder'' would be the "pathfinder" mission for the MESUR program. MESUR regular missions would start landing in 1999. The multi-year MESUR would have 16 more landers, landing in the projected period of 1999-2003, and lasting 10 years. Launches would start in 1996. Several of the landers would carry ''Sojourner''-class rovers. The entire program was projected at a cost of $1 billion US, with per annum spending restricted to $150 million US, starting in FY1994. They were planned to be low-cost missions to Mars, instead of multibillion-dollar missions. The rovers and landers would have instruments and cameras to examine surface rocks, search for water, perform seismography, and observe

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

. The seismology experiments would help determine the internal structure of Mars. After ''Pathfinder'', in 1999, four landers would be launched in a single rocket. At the next launch window in 2001, four more landers would again launch in on a single rocket. Finally in 2003, the last eight landers would launch on two rockets. On 26 June 1992, NASA unveiled the prototype for Mars Sojourner, ''Rocky IV'', on the 25th anniversary of the first US lunar lander. After the loss of ''Mars Observer'', the MESUR program was shelved, and ''Pathfinder'' became part of the NASA

Discovery Program The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level t ...

Missions

''MESUR Pathfinder''

The ''MESUR Pathfinder'' was launched on December 4, 1996 by

aboard a

Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in ...

. After a 7-month voyage it landed on

Ares Vallis Ares Vallis is an outflow channel on Mars, named after the Greek name for Mars: Ares, the god of war; it appears to have been carved by fluids, perhaps water. The valley 'flows' northwest out of the hilly Margaritifer Terra, where the Iani Ch ...

, in a region called

Chryse Planitia Chryse Planitia (Greek, "''Golden Plain''") is a smooth circular plain in the northern equatorial region of Mars close to the Tharsis region to the west, centered at . Chryse Planitia lies partially in the Lunae Palus quadrangle, partially in t ...

, on 4 July 1997. During its voyage the spacecraft had to accomplish four flight adjustments on 10 January, 3 February, 6 May and 25 June. The lander opened, exposing the

rover Rover may refer to: People Name * Constance Rover (1910–2005), English historian * Jolanda de Rover (born 1963), Dutch swimmer * Rover Thomas (c. 1920–1998), Indigenous Australian artist Stage name * Rover (musician), French singer-songw ...

called ''

Sojourner A sojourner is a person who resides temporarily in a place. Sojourner may also refer to: People * Sojourner Truth (1797–1883), abolitionist and women's rights activist * Albert Sojourner (1872–1951), member of the Mississippi House of Rep ...

'' that would go on to execute many experiments on the Martian surface. Although the mission was programmed to last a week to a month, it eventually lasted for almost three months. The final contact with the ''Pathfinder'' was at 10:23 UTC on September 27, 1997. Although the mission planners tried to restore contact during the following five months, the successful mission was terminated on March 10, 1998. After the landing, the ''Mars Pathfinder'' was renamed the Sagan Memorial Station in honor of the famous

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

and planetologist

Carl Sagan Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist and science communicator. His best known scientific contribution is his research on the possibility of extraterrestrial life, including e ...

. The mission had exceeded its goals in the first month.

References

{{Mars Pathfinder Mars Pathfinder Missions to Mars NASA programs