NASA's MarsReconnaissance Orbiter is set to arriveat the red planet Friday after a seven-month trip from Earth.
The largestorbiter sent to Mars in 30 years by NASA, the MRO spacecraft launchedon Aug. 12, 2005 with six primary instruments to study the Martian surface,atmosphere and potential underground water and ice deposits. Armed with what'sbilled as the most powerful camera ever sent to another planet, MRO is expectedpick out choice landing spots for future Mars-bound spacecraft and may evensolve the mystery of a lost 1999 lander in theprocess.
Here's ahandy primer on NASA's MRO spacecraft, its mission and its road to Mars.
10Crowded Martian Neighborhood
The MarsReconnaissance Orbiter (MRO) is a latecomer to what is arguably a bustlingrobotic neighborhood on and around the red planet.
The$450-million MRO probe will become the fourth operational orbiter around Marsand the sixth overall spacecraft to study the planet simultaneously. NASA's twin Mars rovers are rolling acrossthe planet's surface, while its MarsOdyssey, MarsGlobal Surveyor and Europe'sMars Express scan the world from orbit.
9)Double Role
MRO'sinitial mission is a two-year assignment to scan for evidence of past orpresent water while conducting a comprehensive survey of the planet's surfaceand atmosphere. But the job doesn't end there.
Aftercompleting its primary mission, MRO is expected to use its large antenna (seenin this preflight image) to serve as an interplanetary phone operator, relayingdata and instructions between flight controllers on Earth and future landers and rovers on Mars. The entire mission carries a$720 million cost.
8)Subsurface Water Radar
Like theEuropean Space Agency's MarsExpress, MRO sports its own radar tool to probe for ice or liquid waterburied beneath the Martian surface.
The NASAprobe's Shallow Subsurface Radar (SHARAD) is expected to ping the planet in85-millisecond bursts of radar and penetrate up sixth-tenths of a mile (onekilometer) beneath the surface - actual depth depends on the Martian uppercrust. In addition to isolating potential water pockets, the tool will recordthe different rock layers of Mars for geologists to study.
7)Martian Weather
Researchersare eager for MRO's look at Martian weather patterns.After all, Martian winds and dustdevils scrubbed the solar arrays of NASA's Spirit and Opportunity cleanduring their mission, allowing them to draw more power than expected andlengthen their lifetimes.
MRO'sMars Color Imager (MARCI), with its horizon-to-horizon range, is designed torecord daily weather maps, while the Mars Climate Sounder will study thestructure of the planet's atmosphere.
6) AllEyes on Mars
MRO carriesthree cameras and a spectrometer to build a comprehensive picture of theMartian surface. Its HiRISE camera will take a close look at the specificfeatures, while the probe's Context Camera will record strips of terrain morethan 18 miles (30 kilometers) wide. The fish-eyed MARCI is expected to provideglobal coverage and track minute changes in the atmosphere and surface.
Capping thepackage is the CRIS spectrometer, which will hunt for water-related mineralsand determine the composition of the Martian surface in areas as small as ahouse with an accuracy about 10 times sharper than any other tool placed inMars orbit. MRO will also demonstrate an optical navigation camera that may beused for future missions.
5)Glutton for Data
It may be atechnical matter, but MRO's ability to beam data homeis no small feat. The spacecraft's 10-foot (three-meter) antenna is expected totransmit about 34 terabits of data. How much information is that? It's threetimes the amount sent home by NASA's Cassini, DeepSpace 1, Magellan, Mars Odyssey and Mars Global Surveyor missionscombined.
Theelectrical power feeding MRO's antenna - and itsextensive instrument package - stems from two of the largest solar arrays everto fly. Made up of 7,000 solar cells and spanning 220 square feet (20square meters), the arrays generate about twice as much power - two kilowattsat Mars - than required, spacecraft engineers have said.
4)Landing Site Recon
A chiefgoal of the MRO mission is to pick out the best sites for future red planetsurface probes like the MarsScience Laboratory (seen here) and Phoenixlander. Orbital data, for example, used imageryto find the Gusev Crater landing spot for NASA's Spirit rover,while space-based mineral studies pointed to the Meridiani Planum region forOpportunity.
MRO'ssuit of cameras, radar and spectrometers make it a prime instrument in decidingwhere landers may have the most success learningabout Mars' waterypast or hints that the planet may have once been capable ofsupporting life.
3)Pinpointing Liquid Water Effects
With MRO's science instruments working together, researchershope to track all available water-related source and signals at or under Mars.
Scientistsconsider water a key ingredient for life on Earth, and are eager to findunderground caches of it at Mars. Should they be found, such reservoirs couldbe key in determining whether the planet could support life- if only mere microbes clustered around subsurface hot springs - today or inthe distant past.
2) HiRISE Hunt for Mars Polar Lander
MRO'sHigh-Resolution Imaging Science Experiment (HiRISE)camera, with its ability to resolve objects just three feet (one meter) across,may finally allow NASA's MarsPolar Lander to rest in peace.
The lander crashedin December of 1999 and repeatedsearches have turned up some possibletargets, but nothing conclusive. With its sharp eye and low flight orbit -up to 199 miles (320 kilometers - MRO may be able to finally find the lostprobe and put its location to rest.
1) Hitthe Aerobrakes
BeforeNASA's MRO probe can begin any of its mission objectives, it has to slow downfirst.
The probewill rely on a relatively tried and true method called aerobraking, which takes advantage of the drag from aplanet's atmosphere to shed the immense speed a probe builds up during transitand shape its orbit. But the process is not without risk. A navigation errorsent NASA's MarsClimate Orbiter plunging into the Martian atmosphere before it could evenenter orbit in 1999 and begin aerobraking, though theMarsOdyssey and MarsGlobal Surveyor orbiters used the method successfully.
MRO isexpected to begin an estimated hundreds of aerobrakingdips into Mars' atmosphere on March 30, ultimately shaving its initial,extremely elliptical orbit into a near-circular path by November 2006.
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