Comparison of embedded computer systems on board the Mars rovers

The embedded computer systems that are on board the various Mars rovers sent to Mars by NASA have to withstand the high radiation levels and large temperature changes in space and for this reason their computational resources are limited compared to current computer systems commonly used on Earth.^[1]

Operation issues

Direct teleoperation of a rover on Mars is not possible since the round trip communication time between Earth and Mars ranges from 8 to 42 minutes and the Deep Space Network system is only available for use a few times during each Martian day (sol).^[1] Because of this a command team for the rover will plan an entire sol worth of operations and then send it to the rover.^[1]

Autonomy software

A rover uses autonomy software to make decisions based on the observations from its sensors.^[1] The autonomy software on rovers is becoming more advanced and for example with each pair of stereo images the Sojourner rover could generate 20 3D points while the MER rovers can generate 15,000 to 40,000 3D points.^[1]

Performance comparisons

Comparison of embedded computer systems on board the Mars rovers

Rover (mission, organization, year)	CPU	RAM	Flash solid state storage	Operating system	CPU time available for the autonomy software
Sojourner Rover (Pathfinder, NASA, 1997)[1][2][3][4]	100 kHz Intel 80C85	512 KB	176 KB	Custom cyclic executive	Currently unavailable
Pathfinder Lander (NASA, 1997)[1]	20 MHz MFC (IBM RAD6000 Precursor)	128 MB	6 MB (EEPROM)	VxWorks[5] (multitasking)	less than 75%
Spirit and Opportunity (Mars Exploration Rover (MER), NASA, 2004)[1]	20 MHz IBM RAD6000	128 MB	256 MB	VxWorks (multitasking)	less than 75%
Curiosity (Mars Science Laboratory (MSL), NASA, 2011)[1][6][6][7]	200 MHz IBM RAD750	256 MB	2 GB	VxWorks (multitasking)	less than 75%

See also

• Radiation hardening

References

1. ^ ^{a b c d e f g h i} Max Bajracharya, Mark W. Maimone, and Daniel Helmick (2008) (Jet Propulsion Laboratory and California Institute of Technology); Autonomy for Mars rovers: past, present, and future; published in: Computer, a journal of the IEEE Computer Society, December 2008, Volume 41, Number 12, page 45, ISSN 0018-9162.
2. ^ "Mars Pathfinder Frequently Asked Questions: Sojourner Rover". NASA/JPL. April 10, 1997. http://mars.eso.org/MPF/rover/faqs_sojourner.html. Retrieved March 27, 2009. 
3. ^ Donna L. Shirley and Jacob R. Matijevic (May 10, 1997). "Mars Rovers: Past, Present, & Future". NASA/JPL. http://mars.jpl.nasa.gov/MPF/rovercom/data/ROV_PAST.TXT. Retrieved April 18, 2009. 
4. ^ Larry Lange (February 18, 1998). "U.S. plays catch-up as robots crawl into new applications". EETimes.com. http://www.eetimes.com/news/98/994news/robots.html/. Retrieved April 18, 2009. 
5. ^ "Wind River Powers Mars Exploration Rovers—Continues Legacy as Technology Provider for NASA's Space Exploration". Wind River. June 6, 2003. http://www.windriver.com/news/press/pr.html?ID=314. Retrieved August 28, 2009. 
6. ^ ^{a b} "Mars Science Laboratory: Mission: Rover: Brains". NASA/JPL. http://marsprogram.jpl.nasa.gov/msl/mission/rover/brains/. Retrieved March 27, 2009. 
7. ^ "BAE SYSTEMS COMPUTERS TO MANAGE DATA PROCESSING AND COMMAND FOR UPCOMING SATELLITE MISSIONS". BAE Systems. June 17, 2008. http://www.baesystems.com/Newsroom/NewsReleases/autoGen_108517143749.html. Retrieved November 17, 2008.