Mars rover
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Mars rovers are spacecraft which move on the Martian surface after landing. (Only two successful non-Martian rovers were sent into space, Lunokhod: E-8 No. 203 and E-8 No. 204, by the USSR in the 1970s to the moon.[1]) Rovers have advantages over stationary landers, in that they:
- Examine more territory
- Can be directed to interesting features
- Place themselves in sunny positions to weather winter months
- Advance the fledgling knowledge of how to perform very remote robotic control. (The latest two rovers on Mars are considerably more sophisticated than earlier ones.)
Their advantages over orbiting spacecraft are that they can:
- Make observations to a microscopic level
- Conduct physical experimentation
Disadvantages of rovers compared to orbiters are:
- Higher chance of failure, due to landing and other risks.
- Being limited to a small area around a landing site which itself is only approximately anticipated.
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[edit] Rover synopsis
Five rovers were sent to Mars.
- Mars 2, Prop-M rover, 1971, failed
- Mars 3, Prop-M rover, 1971, failed
- Sojourner rover, Mars Pathfinder, landed successfully on July 4, 1997. Communications were lost on September 27, 1997.
- Spirit, Mars Exploration Rover, landed successfully on January 4, 2004. Rover is still operating.
- Opportunity, Mars Exploration Rover, landed successfully on January 25, 2004. Rover is still operating.
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 Mars surface. [2] The Mars 3 rover failed less than a minute after landing and never moved. [3]. Mars 2 and Mars 3 both had companion orbiters which were successful.
The first successful Mars rover (and the third successful rover sent into space) was Sojourner. It was launched by NASA on December 4, 1996, and landed July 4, 1997. [4]
Mars rover Spirit launched June 10, 2003. Opportunity launched July 7, 2003. They were the first to use a new radical landing technique whereby spacecraft mitigated their impact by riding inside a multi-cell balloon that bounced and rolled across the Martian surface, killing its momentum. Spirit landed in Gusev crater on January 4, 2004. Opportunity landed in the Meridiani Planum on the opposite side of Mars, January 25, 2004.
These Mars rovers are in development:
- Mars Science Laboratory, by NASA. Planned Mars launch 2009.
- ExoMars, by the ESA. Planned Mars arrival 2014.
[edit] NASA rover mission goals
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". [5] (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 [6]
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[edit] See also
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