2001 Mars Odyssey:
Mars Odyssey Successfully Orbits the Red Planet
NASA's 2001 Mars Odyssey spacecraft reached Mars on time on Oct. 23, 2001. Its engine fired as programmed, putting the spacecraft in an egg-shaped highly elliptical orbit around the Red Planet.
NASA: FIRST PHOTO FROM 2001 MARS ODYSSEY
Using the Deep Space Network radio communications stations in Goldstone, California, and Canberra, Australia, the NASA control team at the Jet Propulsion Laboratory in Pasadena, California, picked up the first radio signal from the spacecraft as it emerged from behind the planet Mars at 10:55 p.m. EDT. Mars Odyssey was set to edge gradually closer to Mars over 76 days.
Aerobraking. Odyssey powered itself across 285 million miles (460 million kilometers) of space for six months. Then, in a a technique called aerobraking, the spacecraft would use the friction of the atmosphere to lower its orbit to a two hour trip around the planet. Over several weeks, the spacecraft would repeatedly brush against the top of Mars' atmosphere. That would lead to atmospheric drag on the spacecraft, which flight controllers would use to reduce the long elliptical path into a shorter, two-hour circular orbit of approximately 250 miles altitude. Odyssey then would make science maps of the planet below for 917 Earth days.
Aerobraking has been used before on the Mars Global Surveyor and Mars Polar Orbiter missions. Without aerobraking, a spacecraft would need to carry much more fuel.
Helping future probes. It also is equipped to serve as a communications relay for U.S. and international landing craft arriving at Mars in 2004. Those would include NASA's twin Mars Exploration Rovers as well as the European Space Agency's Mars Express Beagle II lander, all of which are scheduled to arrive at Mars in 2004. Odyssey should be able to provide the radio relay function for two Martian years.
Science Instruments. Odyssey carries science instruments for acquiring data to improve our understanding of the planet's climate and geologic history, including searching for water and evidence of life-sustaining environments.
The orbiter carries three different kinds of spectrometers: Thermal Emission Imaging System (THEMIS), Gamma Ray Spectrometer (GRS), and Mars Radiation Environment Experiment (MARIE).
CLICK TO ENLARGE AND CLARIFY THIS NASA PHOTOFirst Image. Odyssey was as on its ninth revolution around the planet, about 13,600 miles above the Red Planet looking down toward the south pole of Mars, when it recorded its first image Oct. 30, 2001. That first thermal infrared image captured the Martian southern hemisphere and the south polar carbon dioxide ice cap at a temperature of about minus 184 F (minus 120 C).
- THEMIS maps the mineralogy and morphology of the Martian surface using a high-resolution camera and a thermal infrared imaging spectrometer. It reports the distribution of minerals, particularly those that can only form in the presence of water.
- GRS, a clone of an instrument lost in the earlier Mars Observer mission, achieves global mapping of the elemental composition of the surface of Mars and determines the abundance of hydrogen in the shallow subsurface. GRS looks for the presence of 20 chemical elements on the surface, including hydrogen in the shallow subsurface. That helps scientists determine the amount and distribution of water ice on the planet.
- MARIE describes the radiation environment in space very close to Mars, especially the risk to human explorers.
At the time, it was late spring in the Martian southern hemisphere. The extremely cold, circular feature shown in blue (in the photo at left) is Mars's south polar carbon dioxide ice cap, which was some 540 miles in diameter at the time. Clouds of cooler air blowing off the cap extended in orange across the image to the left of the cap. The cap would continue to shrink as summer progressed.
FIRST PHOTO FROM
2001 MARS ODYSSEY
click to enlarge nasa photo
The warmest regions occur near local noon. The ring of mountains surrounding the 540-mile diameter impact basin Argyre can be seen in the early afternoon in the upper portion of the photo. The thin blue crescent along the upper limb (edge) of the planet is the Martian atmosphere.
The area covered by the photograph spanned the planet from limb to limb (edge to edge), a distance of more than 3,900 miles. The snapshot of nighttime temperatures demonstrated the camera's night-vision ability to observe Mars' surface in darkness.
Later, Odyssey would move much closer to Mars and be able to see whether or not there are places on the planet where liquid water may be close to the surface, such as hot springs.
While the first image had a resolution directly beneath the spacecraft of 3.4 miles per pixel, the resolution would improve as Odyssey descended into its best mapping orbit where the spacecraft's infrared camera would be able to snap images with a resolution of about 300 feet per pixel.
Titanium Satellite. The framework of 2001 Mars Odyssey is aluminum and titanium, which is a light metal that provides an efficient way of holding down weight while retaining strength. Odyssey's metal structure is something like that of a high-performance fighter aircraft. The spacecraft's main shape is a box 7.2 feet long, 5.6 feet tall and 8.5 feet wide. At launch, it weighed about 1,600 lbs.
Most of Odyssey's systems have backups. That is, they are fully redundant. If a device fails, there is a backup system to compensate. About the only important exception to that is a memory card that collects imaging data from the thermal emission imaging system.
Phoning home. Odyssey's 53 lbs. of communications equipment includes a radio operating in the so-called X-band, which is in the microwave frequency range. It also has a radio in the ultra high frequency (UHF) band. The X-band system is used for communications between Earth and the orbiter, while the UHF system is used for communications between Odyssey and landers on the Martian surface.
It's got a Macintosh computer! All of Odyssey's computing functions are performed by a 25-lb. command and data handling system. The heart of the computer system is a RAD6000 computer, which NASA describes as a radiation-hardened version of the PowerPC chip used on most models of Apple Macintosh computers.
2001 MARS ODYSSEY
NASA ARTIST CONCEPT
The computer has 128 megabytes of random access memory (RAM) and three megabytes of non-volatile memory, which allows the system to maintain data even without power. The computer runs the spacecraft's flight software and controls the spacecraft.
Cards in slots on the computer's main board communicate with external peripherals. For redundancy, there are two identical strings of computer and interface electronics. If one fails the spacecraft can switch to the other.
Odyssey's Mission. An opportunity to go from Earth to Mars comes up every 26 months as the alignment of Earth and Mars in their orbits around the Sun allows spacecraft to travel between the two planets with the least amount of energy. The interplanetary probe 2001 Mars Odyssey -- formerly known as Mars Surveyor 2001 -- was launched on April 7, 2001.
In its science research role from January 2002 through July 2004, Odyssey is the first spacecraft to map the amount and distribution of chemical elements and minerals composing the Martian surface. Odyssey looks in the shallow subsurface of Mars for hydrogen, which might exist as water ice. The probe also records the radiation environment just above Mars to determine its risk to future human explorers.
The science research mission in orbit around Mars will extend across 917 Earth days. That's a full Martian year, which is 29 Earth months. Odyssey will improve our understanding of the Red Planet's climate and geologic history. It will advance our search for liquid water and evidence of past life.
Robot Explorers. Odyssey is part of NASA's long-term Mars Exploration Program of robot exploration of the Red Planet. Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey project for NASA's Office of Space Science. Research scientists at Arizona State University in Tempe, the University of Arizona in Tucson, and NASA's Johnson Space Center, Houston, Texas, operate the science instruments. Lockheed Martin Astronautics, Denver, Colorado, developed and built the orbiter. Mission operations are conducted jointly from JPL and Lockheed Martin. NASA's Langley Research Center in Hampton, Virginia, helped with the aerobraking operation.
