Mars Surveyor '98 was a mission in

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 ...

Mars Exploration Program Mars Exploration Program (MEP) is a long-term effort Exploration of Mars, to explore the planet Mars, funded and led by NASA. Formed in 1993, MEP has made use of orbital spacecraft, lander (spacecraft), landers, and Mars rovers to explore the p ...

that launched the ''

Mars Climate Orbiter The ''Mars Climate Orbiter'' (formerly the Mars Surveyor '98 Orbiter) was a robotic space probe launched by NASA on December 11, 1998, to study the Martian climate, Martian atmosphere, and surface changes and to act as the communications rel ...

'' and the

Mars Polar Lander The Mars Polar Lander, also known as the Mars Surveyor '98 Lander, was a 290-kilogram uncrewed spacecraft lander launched by NASA on January 3, 1999, to study the soil and climate of Planum Australe, a region near the south pole on Mars. It fo ...

to the planet

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 ...

. The mission was to study the Martian weather,

climate Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteoro ...

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and carbon dioxide (CO₂) budget, to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes. The Mars Polar Lander also carried two surface-penetrator probes for the New Millennium Program's Deep Space 2 mission. Both spacecraft were launched in 1998 and both were lost.

Spacecraft

Orbiter

The orbiter was lost due to a miscalculation in trajectory caused by an unintended and undetected mismatch between

metric Metric or metrical may refer to: Measuring * Metric system, an internationally adopted decimal system of measurement * An adjective indicating relation to measurement in general, or a noun describing a specific type of measurement Mathematics ...

and

English units English units were the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxons, Anglo-Saxon and Ancient Roman units of measurement, Roman systems of units. V ...

of measurement. The use of metric units as well as the data formats to employ were specified in a navigation software interface specification (SIS) published by JPL in 1996. Despite this, the flight operations team at

Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...

provided impulse data in English units of

pound-force The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force used in some systems of measurement, including English Engineering units and the foot–pound–second system. Pound-force should not be confused with poun ...

seconds rather than newton seconds. These values were incorrect by a factor of 4.45 (1 lbf = 4.45 N). This caused erroneous course corrections that caused the orbiter to descend too low in Mars's atmosphere. The vehicle either burned up or bounced off into space.

Lander

Investigators concluded that the most likely cause of the lander's failure was a spurious sensor signal associated with the craft's legs falsely indicating the craft had touched down when in fact it was some 40 meters above the surface. When the landing legs unfolded they made a bouncing motion that accidentally set off the landing sensors, causing the descent engines to shut down prematurely and the lander to fall. Another possible reason for failure was inadequate preheating of

catalysis Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

beds for the pulsing rocket thrusters.

Hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

fuel decomposes on the beds to make hot gases that are forced out of the

rocket nozzle A rocket engine nozzle is a propelling nozzle (usually of the de Laval type) used in a rocket engine to expand and accelerate combustion products to high supersonic velocities. Simply: propellants pressurized by either pumps or high pressure u ...

s, generating

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

; in crash review tests cold catalysis beds caused misfiring and

instability In dynamical systems instability means that some of the outputs or internal states increase with time, without bounds. Not all systems that are not stable are unstable; systems can also be marginally stable or exhibit limit cycle behavior. ...

Mission

The Mars Surveyor 1998 program spacecraft development cost US$193.1 million. Launch costs for the Mars Surveyor '98 Program was estimated at US$91.7 million and mission operations at US$42.8 million. The Mars Climate Orbiter was part of NASA's 10-year Mars Surveyor Program, with launches every 26 months when the Earth and Mars are favorably positioned.

References

{{DEFAULTSORT:Mars Surveyor '98 Mars Exploration Program Missions to Mars NASA programs

Spacecraft

Orbiter

Lander

Mission

See also

References