MESUR, the ''M''ars ''E''nvironmental ''SUR''vey was a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

program designed to explore the planet Mars 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 space probe launched by NASA on September 25, 1992, to study the Martian surface, atmosphere, climate and magnetic field. During the inte ...

''. 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 and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

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 A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, Types of volcanic eruptions, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to f ...

, and observe

meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not ...

. 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.

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. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...

. 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 Cha ...

, 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 th ...

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

, 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 * Constance Rover (1910–2005), English historian * Jolanda de Rover (born 1963), Dutch swimmer * Rover Thomas (c. 1920–1998), Indigenous Australian artist Places * Rover, Arkansas, US * Rover, Missouri, US * ...

called ''

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

'' 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 their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

and

planetologist Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of their fo ...

Carl Sagan Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on ext ...

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

References

{{Mars Pathfinder Mars Pathfinder Missions to Mars NASA programs