Mars Surveyor '98 program
Encyclopedia
The Mars Surveyor '98 program comprised two spacecraft launched separately, the Mars Climate Orbiter
(formerly the Mars Surveyor '98 Orbiter) and the Mars Polar Lander
(formerly the Mars Surveyor '98 Lander); on board the Mars Polar Lander spacecraft were two surface-penetrator probes (Deep Space 2
). The two missions were to study the Martian weather, climate, and water and carbon dioxide budget, to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes.
Both spacecraft were launched during the 1998 Mars
orbit insertion
launch window
. Both were lost, including the penetrator probes.
The orbiter was lost due to a miscalculation in trajectory caused by an unintended and undetected mismatch between metric
and English units 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.
Investigators concluded that the most likely cause of the Lander’s failure was that a spurious sensor signal associated with the craft’s legs falsely indicated that 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
beds for the pulsing rocket thrusters. Hydrazine
fuel decomposes on the beds to make hot gases that are forced out of the rocket nozzles, generating thrust
; in crash review tests cold catalysis beds caused misfiring
and instability
.
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.
Mars Climate Orbiter
The Mars Climate Orbiter was a 338 kilogram robotic space probe launched by NASA on December 11, 1998 to study the Martian climate, atmosphere, surface changes and to act as the communications relay in the Mars Surveyor '98 program, for Mars Polar Lander...
(formerly the Mars Surveyor '98 Orbiter) and the Mars Polar Lander
Mars Polar Lander
The Mars Polar Lander, also referred to 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, as part of the Mars Surveyor '98 mission...
(formerly the Mars Surveyor '98 Lander); on board the Mars Polar Lander spacecraft were two surface-penetrator probes (Deep Space 2
Deep Space 2
Deep Space 2 was a NASA probe which was part of the New Millennium Program. It included two highly advanced miniature space probes which were sent to Mars aboard the Mars Polar Lander in January 1999. The probes were named "Scott" and "Amundsen", in honor of Robert Falcon Scott and Roald Amundsen,...
). The two missions were to study the Martian weather, climate, and water and carbon dioxide budget, to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes.
Both spacecraft were launched during the 1998 Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
orbit insertion
Orbit insertion
Orbit insertion is the spaceflight operation of adjusting a spacecraft’s momentum to allow for entry into a stable orbit around a planet, moon, or other celestial body...
launch window
Launch window
Launch window is a term used in spaceflight to describe a time period in which a particular launch vehicle must be launched. If the rocket does not launch within the "window", it has to wait for the next window....
. Both were lost, including the penetrator probes.
The orbiter was lost due to a miscalculation in trajectory caused by an unintended and undetected mismatch between metric
Si
Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
and English units 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
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
provided impulse data in English units of pound-force
Pound-force
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
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.
Investigators concluded that the most likely cause of the Lander’s failure was that a spurious sensor signal associated with the craft’s legs falsely indicated that 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
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....
beds for the pulsing rocket thrusters. Hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
fuel decomposes on the beds to make hot gases that are forced out of the rocket nozzles, generating thrust
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
; in crash review tests cold catalysis beds caused misfiring
Misfire
Misfire may refer to:* Misfire , the Transformers character* Misfire , an episode from That '70s Show* Misfiring behavior, in biology* An engine misfire, see catalytic converter* A song on Queen's album Sheer Heart Attack...
and instability
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...
.
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.