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 US federal government responsible for the civil List of government space agencies, space program ...

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

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 re ...

and the

Mars Polar Lander The Mars Polar Lander, also known as the Mars Surveyor '98 Lander, was a 290-kilogram robotic 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 form ...

to the planet

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

. The mission was to study the Martian weather,

climate Climate is the long-term weather pattern in an area, 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 meteorologi ...

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

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 New Millennium Program (NMP) was a NASA project with focus on engineering validation of new technologies for space applications. Funding for the program was eliminated from the FY2009 budget by the 110th United States Congress, effectively leading ...

Deep Space 2 Deep Space 2 was a NASA space probe, part of the New Millennium Program. It included two highly advanced miniature space probes that were sent to Mars aboard the Mars Polar Lander in January 1999. The probes were named "Scott" and "Amundsen", in ...

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: * 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 In mathem ...

and

English units English units are 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-Saxon and Roman systems of units. Various standards have applied to English units at ...

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 provided impulse data in English units of pound-force 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 process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

beds for the pulsing rocket thrusters. Hydrazine 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 ul ...

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 sys ...

; in crash review tests cold catalysis beds caused misfiring and

instability In numerous fields of study, the component of instability within a system is generally characterized by some of the outputs or internal states growing without bounds. Not all systems that are not stable are unstable; systems can also be mar ...

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