Mars rover

MSL mockup compared with the Mars Exploration Rover and Sojourner rover by the Jet Propulsion Laboratory on May 12, 2008

Mars rover Sojourner atop its lander Pathfinder at the National Air and Space Museum

A Mars rover is an automated motor vehicle which propels itself across the surface of the planet Mars after landing.

Rovers have several advantages over stationary landers: they examine more territory, they can be directed to interesting features, they can place themselves in sunny positions to weather winter months and they can advance the knowledge of how to perform very remote robotic vehicle control.

There have been three successful Mars rovers, all of which were robotically operated. The Jet Propulsion Laboratory managed the Mars Pathfinder mission with its Sojourner rover and currently manages the Mars Exploration Rover mission with its two rovers, Spirit and Opportunity, for NASA’s Office of Space Science, Washington, DC. (There have also been two successful non-Martian robotic rovers: in the 1970s the USSR sent two Lunokhod rovers to the Moon.^[1])

Rover synopsis

A Martian sunset at Gusev Crater. Spirit rover, May 19, 2005.

Five rovers have been sent to Mars:

• Mars 2, Prop-M rover, 1971, succeeded* Mars 3, Prop-M rover, 1971, failed landing

The Mars 2 and 3 spacecraft from the USSR, had identical 4.5 kg Prop-M rovers. They were to move on skis while connected to the landers with cables. The Mars 2 rover crashed into the Martian surface.^[2] The Mars 3 rover failed less than a minute after landing and never moved.^[2] Mars 2 and Mars 3 both had companion orbiters which were successful.

• Sojourner rover, Mars Pathfinder, landed successfully on July 4, 1997. Communications were lost on September 27, 1997.
• Spirit (MER-A), Mars Exploration Rover, landed successfully on January 4, 2004. Nearly 6 years after the original mission limit, Spirit had covered a total distance of 7.73 km (4.80 mi) but its wheels were trapped in sand.^[3] Around January 26, 2010, NASA admitted defeat in its efforts to free the rover and stated that it would now function as a stationary science platform.^[4] Since March 22, 2010 there has been no communication from the rover, and as of May 25, 2011 NASA will no longer attempt to re-establish communication.^[5]
• Opportunity (MER-B), Mars Exploration Rover, landed successfully on January 25, 2004. Rover was still operating as of October 2011, having surpassed the previous record for longevity of a surface mission to Mars on May 20, 2010.^[6][7]

Prop-M rovers

These Mars rovers are in development:

• Curiosity, Mars Science Laboratory, by NASA. Planned Mars launch Late 2011.^[8]
• ExoMars, by the ESA. Planned Mars launch 2018.^[9]

One experimental design, not proposed for any actual mission, is:

• Mars Tumbleweed Rover, a wind-propelled rover.^[10]

Panorama of Husband Hill taken by MER-A Spirit Rover, November 23–28, 2005.

NASA rover mission goals

Wheel size comparison: Mars Pathfinder, Mars Exploration Rover, Mars Science Laboratory.

NASA distinguishes between "mission" objectives and "science" objectives. Mission objectives are related to progress in space technology and development processes. Science objectives are met by the instruments during their mission in space.

The details of rover science vary according to equipment carried. The primary goal of the Spirit and Opportunity rovers is to discover "the history of water on Mars".^[11] (The presence of usable water would greatly reduce manned mission cost.)

The four science goals of NASA's long-term Mars Exploration Program are:

• Determine whether life ever arose on Mars
• Characterize the climate of Mars
• Characterize the geology of Mars
• Prepare for human exploration^[12]

See also

• Comparison of embedded computer systems on board the Mars rovers
• Radiation hardening

Footnotes

1. ^ "Russia's unmanned missions toward the Moon". www.russianspaceweb.com. http://www.russianspaceweb.com/spacecraft_planetary_lunar.html. Retrieved 2008-06-25. 
2. ^ ^{a b} "Mars 2 Lander". NASA NSSDC. http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=1971-045D. Retrieved 2008-06-25. 
3. ^ Boyle, Alan. "Good moves on Mars". MSNBC. http://cosmiclog.msnbc.msn.com/archive/2010/01/21/2181157.aspx. Retrieved 2010-01-22. 
4. ^ Times, International Business (January 26, 2010). "NASA concedes defeat in effort to free rover". http://www.ibtimes.com/articles/20100126/nasa-concedes-defeat-effort-free-rover.htm. Retrieved 2010-01-26. 
5. ^ "NASA Concludes Attempts To Contact Mars Rover Spirit". NASA. May 24, 2011. http://marsrover.nasa.gov/newsroom/pressreleases/20110524a.html. 
6. ^ "NASA's Mars Rovers Set Surface Longevity Record". NASA. May 19, 2010. http://www.nasa.gov/mission_pages/mer/news/mer20100519.html. 
7. ^ Spirit Rover Marks Seven Years On Mars, Still Stuck (Fox News, 03 January 2011)
8. ^ Chang, Kenneth (July 22, 2011). "NASA Picks Rover's Destination: A Mountain on Mars". The New York Times. http://www.nytimes.com/2011/07/23/science/space/23mars.html?_r=1. 
9. ^ Michael A. Taverna (October 19, 2009). "ESA Proposes Two ExoMars Missions". Aviation Week. http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/Exomars101909.xml&headline=ESA%20Proposes%20Two%20ExoMars%20Missions. Retrieved 2010-06-24. 
10. ^ Kimberly W. Land (May 13, 2003). "A new way to explore the surface of Mars". NASA. http://www.nasa.gov/centers/langley/news/releases/2003/03-029.html. Retrieved 2011-04-04. 
11. ^ "Mars Exploration Rover Mission: Overview". marsrovers.nasa.gov. http://marsrovers.nasa.gov/overview/. Retrieved 2008-06-25. 
12. ^ "Mars Exploration Rover Mission: Science - Looking for signs of past water on Mars". marsrovers.nasa.gov. http://marsrovers.nasa.gov/science/. Retrieved 2008-06-25. 

External links

• NASA official Mars Rover website