Mars Observer
Encyclopedia
The Mars Observer spacecraft, also known as the Mars Geoscience/Climatology Orbiter, was a 1,018-kilogram (2,244 lb
) robotic
space probe
launched by NASA
on September 25, 1992 to study the Martian surface, atmosphere, climate and magnetic field. During the interplanetary cruise phase, communication with the spacecraft was lost on August 21, 1993, 3 days prior to orbital insertion. Attempts to re-establish communication with the spacecraft were unsuccessful.
was planned to expand on the vast information already gathered by the Viking program
. Preliminary mission goals expected the probe to provide planetary magnetic field data, detection of certain spectral line
signatures of minerals on the surface, images of the surface at 1 meter/pixel
and global elevation data.
Mars Observer was originally planned to be launched in 1990 by a Space Shuttle Orbiter
. The possibility for an expendable rocket to be used was also suggested, if the spacecraft would be designed to meet certain constraints. On March 12th, 1987, the mission was rescheduled for launch in 1992, in lieu of other backlogged missions (Galileo, Magellan
, Ulysses). Along with a launch delay, budget overruns necessitated the elimination of two instruments to meet the 1992 planned launch. As the development matured, the primary science objectives were finalized as:
-Ku-band satellite design was used extensively for the spacecraft bus, propulsion, thermal protection, and solar array. RCA TIROS and DMSP Block 50-2
satellite designs were also utilized in the implementing the Attitude and Articulation Control System (AACS), command and data handling subsystem, and power subsystem, into Mars Observer. Other elements such as the bipropellant components and high-gain antenna were designed specifically for the mission.
in Florida, aboard a Commercial Titan III CT-4
launch vehicle. The complete burn sequence lasted for 34 minutes after a solid-fuel Transfer Orbit Stage
placed the spacecraft into an 11 month, Mars transfer trajectory, at a final speed of 5.28-kilometers/second with respect to Mars.
On August 25, 1992, particulate contamination was found within the spacecraft. After a full inspection, a cleaning was determined necessary and was performed on August 29. The suspected cause of the contamination were measures taken to protect the spacecraft prior to the landfall of Hurricane Andrew
which struck the coast of Florida on August 24.
launched in 1996, Mars Climate Orbiter
launched in 1998, 2001 Mars Odyssey
launched in 2001, Mars Reconnaissance Orbiter
launched in 2005.
On August 24, 1993, Mars Observer would turn 180-degrees and ignite the bipropellant thrusters to slow the spacecraft, entering into a highly elliptical orbit. Over the next three months, subsequent "transfer to lower orbit" (TLO) maneuvers would be performed as the spacecraft reached periapsis, eventually resulting in an approximately circular, 118-minute orbit around Mars.
The primary mission was to begin on November 23, 1993, collecting data during one Martian year (approximately 687 Earth days). The first global map was expected to be completed on December 16, followed by solar conjunction
beginning on December 20, and lasting for nineteen days, ending on January 3, 1994; during this time, mission operations would be suspended as radio contact would not be possible.
Orbiting Mars at an approximate speed of 3.4-kilometers/second, the spacecraft would travel around Mars in a north to south, polar orbit. As the spacecraft circles the planet, horizon sensors indicate the orientation of the spacecraft while the reaction wheels would maintain the orientation of the instruments, towards Mars. The chosen orbit was also sun-synchronous, allowing the daylit side of Mars to always be captured during the mid-afternoon of each Martian Sol. While some instruments could provide a real-time data link when Earth was in view of the spacecraft, data would also be recorded to the digital tape recorders and played back to Earth each day. Over 75-gigabyte
s of scientific data was expected to be yielded during the primary mission, much more than any previous mission to Mars. The end of the operable life for the spacecraft was expected to be limited by the supply of propellant and the condition of the batteries.
orbital insertion, there was an "inexplicable" loss of contact with Mars Observer. New commands were sent every 20 minutes in the hopes that the spacecraft had drifted off course and could regain contact. However, the attempt was unsuccessful. It is unknown whether the spacecraft was able to follow its automatic programming and go into Mars orbit or if it flew by Mars and is now in a heliocentric orbit
.
On January 4, 1994, an independent investigation board from the Naval Research Laboratory, announced their findings: the most probable cause in the loss of communication was a rupture of the fuel pressurization tank in the spacecraft's propulsion system. It is believed that hypergolic fuel may have leaked past valves in the system during the cruise to Mars, allowing the fuel and oxidizer to combine prematurely before reaching the combustion chamber. The leaking fuel and gas probably resulted in a high spin rate, causing the spacecraft to enter into the "contingency mode"; this interrupted the stored command sequence and did not turn the transmitter on. The engine was derived from one belonging to an Earth orbital satellite and was not designed to lie dormant for months before being fired.
LB
-Codes:*.lb, the Internet country code top-level domain for Lebanon*Labrador's former postal abbreviation*Lloyd Aéreo Boliviano airline's IATA code*Luxembourgish language's ISO 639 alpha-2 code*Lebanon's ISO 3166-1 alpha-2 country code...
) robotic
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
space probe
Space probe
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
launched by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
on September 25, 1992 to study the Martian surface, atmosphere, climate and magnetic field. During the interplanetary cruise phase, communication with the spacecraft was lost on August 21, 1993, 3 days prior to orbital insertion. Attempts to re-establish communication with the spacecraft were unsuccessful.
History
In 1984, a high priority mission to Mars was set forth by the Solar System Exploration Committee. Then titled the Mars Geoscience/Climatology Orbiter, the Martian orbiterOrbiter
An orbiter is a space probe that orbits a planet.-Asteroids:*NEAR Shoemaker...
was planned to expand on the vast information already gathered by the Viking program
Viking program
The Viking program consisted of a pair of American space probes sent to Mars, Viking 1 and Viking 2. Each spacecraft was composed of two main parts, an orbiter designed to photograph the surface of Mars from orbit, and a lander designed to study the planet from the surface...
. Preliminary mission goals expected the probe to provide planetary magnetic field data, detection of certain spectral line
Spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies.- Types of line spectra :...
signatures of minerals on the surface, images of the surface at 1 meter/pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
and global elevation data.
Mars Observer was originally planned to be launched in 1990 by a Space Shuttle Orbiter
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
. The possibility for an expendable rocket to be used was also suggested, if the spacecraft would be designed to meet certain constraints. On March 12th, 1987, the mission was rescheduled for launch in 1992, in lieu of other backlogged missions (Galileo, Magellan
Magellan probe
The Magellan spacecraft, also referred to as the Venus Radar Mapper, was a 1,035-kilogram robotic space probe launched by NASA on May 4, 1989, to map the surface of Venus using Synthetic Aperture Radar and measure the planetary gravity...
, Ulysses). Along with a launch delay, budget overruns necessitated the elimination of two instruments to meet the 1992 planned launch. As the development matured, the primary science objectives were finalized as:
- Determine the global elemental and mineralogical character of the surface material.
- Define globally the topographyTopographyTopography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...
and gravitational field. - Establish the nature of the Martian magnetic fieldMagnetic fieldA magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
. - Determine the temporal and spatial distribution, abundance, sources, and sinks of volatiles and dust over a seasonal cycle.
- Explore the structure and circulation of the atmosphere.
Spacecraft design
The Mars Observer spacecraft bus measured 1.1-meters tall, 2.2-meters wide, and 1.6-meters deep. The spacecraft was based on previous satellite designs, originally intended and developed to orbit Earth. The RCA SatcomSatcom (satellite)
The Satcom series was a family of communications satellites originally developed and operated by RCA American Communications . Satcom was one of the early geostationary satellites; the first were the Syncom series, in 1964. The first Satcom satellite, Satcom 1, was launched on December 13, 1975...
-Ku-band satellite design was used extensively for the spacecraft bus, propulsion, thermal protection, and solar array. RCA TIROS and DMSP Block 50-2
Defense Meteorological Satellite Program
The Defense Meteorological Satellite Program monitors meteorological, oceanographic, and solar-terrestrial physics for the United States Department of Defense. The program is now run by the National Oceanic and Atmospheric Administration. The mission of the satellites was revealed in March 1973...
satellite designs were also utilized in the implementing the Attitude and Articulation Control System (AACS), command and data handling subsystem, and power subsystem, into Mars Observer. Other elements such as the bipropellant components and high-gain antenna were designed specifically for the mission.
Attitude control and propulsion
- The spacecraft was three-axis stabilized with four reaction wheels and twenty-four thrustersReaction engineA reaction engine is an engine or motor which provides propulsion by expelling reaction mass, in accordance with Newton's third law of motion...
with 1346-kilograms of propellant. The propulsion system is a high thrust, Monomethyl hydrazine/nitrogen tetroxide bipropellant system for larger maneuvers and a lower thrust hydrazineHydrazineHydrazine 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...
monopropellantMonopropellant rocketA monopropellant rocket is a rocket that uses a single chemical as its propellant.-Chemical-reaction monopropellant rockets:...
system for minor orbital corrections during the mission. Of the bipropellant thrusters, four located on the aft, provide 490-Newtons of thrust for course corrections, control of the spacecraft during the Mars orbital insertion maneuver and large orbit corrections during the mission; another four, located on along the sides of the spacecraft, provide 22-Newtons for controlling roll maneuvers. Of the hydrazine thrusters, eight provide 4.5-Newtons to control orbit trim maneuvers; another eight provide 0.9-Newtons for offsetting, or "desaturating", the reaction wheels. To determine the orientation of the spacecraft, a horizon sensor, a 6-slit star scanner, and five sun sensors were included.
Communications
- For telecommunications, the spacecraft included a two-axis gimbalGimbalA gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of two gimbals, one mounted on the other with pivot axes orthogonal, may be used to allow an object mounted on the innermost gimbal to remain immobile regardless of the motion of its support...
ed 1.5-meter, parabolic high-gain antennaHigh-gain antennaA high-gain antenna is an antenna with a focused, narrow radiowave beam width. This narrow beam width allows more precise targeting of the radio signal - also known as a directional antenna...
, mounted to a 6-meter boom to communicate with the Deep Space NetworkDeep Space NetworkThe Deep Space Network, or DSN, is a world-wide network of large antennas and communication facilities that supports interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected...
across the X-band using two GFP NASA X-band transponders (NXTs) and two GFP command detector units (CDUs). An assembly of six low-gain antennas, and a single medium-gain antenna were also included, to be used during the cruise phase while the high-gain antenna remained stowed, and for contingency measures should communications through the high-gain antenna become restricted. When broadcasting to the Deep Space Network, a maximum of 10.66 kilobytes/second could be achieved while the spacecraft could receive commands at a maximum bandwidth of 62.5-bytes/second.
Power
- Power was supplied to the spacecraft through a six panel solar array, measuring 7.0-meters wide and 3.7-meters tall, and would provide an average of 1147-Watts when in orbit. To power the spacecraft while occludedOccultationAn occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy . It can also refer to any situation wherein an object in the foreground blocks from view an object in the background...
from the Sun, two 42-amp-hour Nickel-Cadmium batteriesNickel-cadmium batteryThe nickel–cadmium battery ' is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes....
were included; the batteries would recharge as tthe solar array received sunlight.
Computer
- The computing system on the spacecraft was a retooling of the system used on the TIROS and DMSP satellites. The semiautonomous system was able to store up to 2000 commands in the included 64-kilobytes of Random-access memoryRandom-access memoryRandom access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
, and execute them at a maximum rate of 12.5-commands/second; commands could also provide sufficient autonomous operation of the spacecraft for up to sixty days. To record data, redundant digital tape recorders (DTR) were included and each capable of storing up to 187.5-megabytes, for later playback to the Deep Space Network.
Scientific instruments
| Mars Observer Camera Mars Orbiter Camera The Mars Orbiter Camera or Mars Observer Camera was a scientific instrument on board the Mars Observer and Mars Global Surveyor spacecrafts... (MOC) |
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EWLINE
Consists of narrow-angle and wide-angle telescopic cameras to study the meteorology/climatology and geoscience of Mars. |
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| Mars Observer Laser Altimeter Mars Orbiter Laser Altimeter right|thumb|260px|MOLA topographic images of the two hemispheres of Mars. This image appeared on the cover of Science magazine in May 1999.The Mars Orbiter Laser Altimeter was one of five instruments on board the Mars Global Surveyor spacecraft, which operated in Mars orbit from September 1997 to... (MOLA) |
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EWLINE
A laser altimeter used to define the topography Topography Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids... of 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... . |
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| Thermal Emission Spectrometer Thermal Emission Spectrometer The Thermal Emission Spectrometer is an instrument on board Mars Global Surveyor. TES collects two types of data, hyperspectral thermal infrared data from 6 to 50 micrometers and bolometric visible-NIR measurements... (TES) |
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EWLINE
Uses three sensors (Michelson interferometer, solar reflectance sensor, broadband radiance sensor) to measure thermal infrared emissions to map the mineral content of surface rocks, frosts and the composition of clouds . |
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| Pressure Modulator Infrared Radiometer (PMIRR) | ||||
EWLINE
Uses narrow-band radiometric channels and two pressure modulation cells to measure atmospheric and surface emissions in the thermal infrared and a visible channel to measure dust particles and condensates in the atmosphere and on the surface at varying longitudes and seasons. |
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| Gamma Ray Spectrometer (GRS) | ||||
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EWLINE
Records the spectrum of gamma rays and neutron Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... s emitted by the radioactive decay of elements contained in the Martian surface. |
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| Magnetometer and Electron Reflectometer (MAG/ER) | ||||
EWLINE
Uses the components of the on-board telecommunications system and the stations of the Deep Space Network Deep Space Network The Deep Space Network, or DSN, is a world-wide network of large antennas and communication facilities that supports interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected... to collect data on the nature of the magnetic field Magnetic field A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;... and interactions the field may have with solar wind Solar wind The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time... . |
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| Radio Science experiment (RS) | ||||
EWLINE
Collects data on the gravity field and the Martian atmospheric structure with a special emphasis on temporal changes near the polar regions. |
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| Mars Balloon Relay (MBR) | ||||
Planned as augmentation to return data from the penetrators and surface stations of the Russian Mars '94 mission and from penetrators, surface stations, a rover, and a balloon from the Mars '96 Mars 96 Mars 96 was a failed Mars mission launched in 1996 to investigate Mars by the Russian Space Forces and not directly related to the Soviet Mars probe program of the same name. After failure of the second fourth-stage burn, the probe assembly re-entered the Earth's atmosphere, breaking up over a... mission. |
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Mission profile
| Timeline of operations | |||||||||||
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| Mission declared a loss. No further attempts to contact. | |||||||||||
Launch and trajectory
Mars Observer was launched on September 25, 1992 at 17:05:01 UTC by the National Aeronautics and Space Administration from Space Launch Complex 40 at the Cape Canaveral Air Force StationCape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...
in Florida, aboard a Commercial Titan III CT-4
Titan III
The Titan IIIC was a space booster used by the United States Air Force. It was launched from Cape Canaveral Air Force Station, FL., and Vandenberg Air Force Base, CA. It was planned to be used as a launch vehicle in the cancelled Dyna-Soar and Manned Orbiting Laboratory programs...
launch vehicle. The complete burn sequence lasted for 34 minutes after a solid-fuel Transfer Orbit Stage
Transfer orbit stage
The Transfer Orbit Stage was an upper stage developed by Martin Marietta for Orbital Sciences Corporation during the late 1980s and early 1990s. The TOS was designed to be a lower-cost alternative to Inertial Upper Stage and Centaur upper stages...
placed the spacecraft into an 11 month, Mars transfer trajectory, at a final speed of 5.28-kilometers/second with respect to Mars.
On August 25, 1992, particulate contamination was found within the spacecraft. After a full inspection, a cleaning was determined necessary and was performed on August 29. The suspected cause of the contamination were measures taken to protect the spacecraft prior to the landfall of Hurricane Andrew
Hurricane Andrew
Hurricane Andrew was the third Category 5 hurricane to make landfall in the United States, after the Labor Day Hurricane of 1935 and Hurricane Camille in 1969. Andrew was the first named storm and only major hurricane of the otherwise inactive 1992 Atlantic hurricane season...
which struck the coast of Florida on August 24.
Encounter with Mars
Mars Observer was scheduled to perform an orbital insertion maneuver on August 24, 1993. However due to complications, contact with the spacecraft was lost on August 21, 1993, after a routine operation likely caused a rupture in the bipropellant system, resulting in the loss of the spacecraft. Although none of the primary objectives were achieved, the mission provided interplanetary cruise phase data, collected up to the date of last contact. This data would be useful for subsequent missions to Mars. Science instruments originally developed for Mars Observer were placed on three future orbiters to complete the mission objectives: Mars Global SurveyorMars Global Surveyor
The Mars Global Surveyor was a US spacecraft developed by NASA's Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 10-year absence. It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2...
launched in 1996, Mars Climate Orbiter
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...
launched in 1998, 2001 Mars Odyssey
2001 Mars Odyssey
2001 Mars Odyssey is a robotic spacecraft orbiting the planet Mars. The project was developed by NASA, and contracted out to Lockheed Martin, with an expected cost for the entire mission of US$297 million. Its mission is to use spectrometers and electronic imagers to hunt for evidence of past or...
launched in 2001, Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter
Mars Reconnaissance Orbiter is a NASA multipurpose spacecraft designed to conduct reconnaissance and Exploration of Mars from orbit...
launched in 2005.
Intended operations
 |
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On August 24, 1993, Mars Observer would turn 180-degrees and ignite the bipropellant thrusters to slow the spacecraft, entering into a highly elliptical orbit. Over the next three months, subsequent "transfer to lower orbit" (TLO) maneuvers would be performed as the spacecraft reached periapsis, eventually resulting in an approximately circular, 118-minute orbit around Mars.
The primary mission was to begin on November 23, 1993, collecting data during one Martian year (approximately 687 Earth days). The first global map was expected to be completed on December 16, followed by solar conjunction
Solar conjunction
Solar conjunction occurs when a planet or other solar system object is on the opposite side of the sun from the Earth. From an Earth reference, the object will pass between the sun and the Earth. Communication with any spacecraft in solar conjunction will be severely limited due to the sun's...
beginning on December 20, and lasting for nineteen days, ending on January 3, 1994; during this time, mission operations would be suspended as radio contact would not be possible.
Orbiting Mars at an approximate speed of 3.4-kilometers/second, the spacecraft would travel around Mars in a north to south, polar orbit. As the spacecraft circles the planet, horizon sensors indicate the orientation of the spacecraft while the reaction wheels would maintain the orientation of the instruments, towards Mars. The chosen orbit was also sun-synchronous, allowing the daylit side of Mars to always be captured during the mid-afternoon of each Martian Sol. While some instruments could provide a real-time data link when Earth was in view of the spacecraft, data would also be recorded to the digital tape recorders and played back to Earth each day. Over 75-gigabyte
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
s of scientific data was expected to be yielded during the primary mission, much more than any previous mission to Mars. The end of the operable life for the spacecraft was expected to be limited by the supply of propellant and the condition of the batteries.
Communications loss
On August 21, 1993, at 01:00 UTC, three days prior to the scheduled MarsMars
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...
orbital insertion, there was an "inexplicable" loss of contact with Mars Observer. New commands were sent every 20 minutes in the hopes that the spacecraft had drifted off course and could regain contact. However, the attempt was unsuccessful. It is unknown whether the spacecraft was able to follow its automatic programming and go into Mars orbit or if it flew by Mars and is now in a heliocentric orbit
Heliocentric orbit
A heliocentric orbit is an orbit around the Sun. All planets, comets, and asteroids in our Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet...
.
On January 4, 1994, an independent investigation board from the Naval Research Laboratory, announced their findings: the most probable cause in the loss of communication was a rupture of the fuel pressurization tank in the spacecraft's propulsion system. It is believed that hypergolic fuel may have leaked past valves in the system during the cruise to Mars, allowing the fuel and oxidizer to combine prematurely before reaching the combustion chamber. The leaking fuel and gas probably resulted in a high spin rate, causing the spacecraft to enter into the "contingency mode"; this interrupted the stored command sequence and did not turn the transmitter on. The engine was derived from one belonging to an Earth orbital satellite and was not designed to lie dormant for months before being fired.
| Quoted from the report |
|---|
| "Because the telemetry transmitted from the Observer had been commanded off and subsequent efforts to locate or communicate with the spacecraft failed, the board was unable to find conclusive evidence pointing to a particular event that caused the loss of the Observer. However, after conducting extensive analyses, the board reported that the most probable cause of the loss of communications with the spacecraft on Aug. 21, 1993, was a rupture of the fuel (monomethyl hydrazine (MMH)) pressurization side of the spacecraft's propulsion system, resulting in a pressurized leak of both helium gas and liquid MMH under the spacecraft's thermal blanket. The gas and liquid would most likely have leaked out from under the blanket in an unsymmetrical manner, resulting in a net spin rate. This high spin rate would cause the spacecraft to enter into the "contingency mode," which interrupted the stored command sequence and thus, did not turn the transmitter on. Additionally, this high spin rate precluded proper orientation of the solar arrays, resulting in discharge of the batteries. However, the spin effect may be academic, because the released MMH would likely attack and damage critical electrical circuits within the spacecraft. The board's study concluded that the propulsion system failure most probably was caused by the inadvertent mixing and the reaction of nitrogen tetroxide (NTO) and MMH within titanium pressurization tubing, during the helium pressurization of the fuel tanks. This reaction caused the tubing to rupture, resulting in helium and MMH being released from the tubing, thus forcing the spacecraft into a catastrophic spin and also damaging critical electrical circuits." |
See also
- Exploration of MarsExploration of MarsThe exploration of Mars has been an important part of the space exploration programs of the Soviet Union, the United States, Europe, and Japan. Dozens of robotic spacecraft, including orbiters, landers, and rovers, have been launched toward Mars since the 1960s...
- Space explorationSpace explorationSpace exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....
- Unmanned space missions
- Planetary Observer programPlanetary Observer programThe Planetary Observer program is a cancelled space exploration program designed by NASA to provide cheaper planetary orbiters by utilising Earth-orbiting satellite components and technology, using solar panels for power, and a common spacecraft bus platform for all Planetary Observer-class probes...
External links
- Mars Observer launch press kit
- Mars Observer Mission Profile by NASA's Solar System Exploration
- Mars Observer at NSSDC Master Catalog
- The Loss of Mars Observer at Malin Space Science Systems
- NASA - Mars Observer