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Comparison of embedded computer systems on board the Mars rovers
open-in-new
<h2 id="in-operation">In operation</h2> <p>Direct <a href="/facts/Teleoperation/bpYyorPE">teleoperation</a> of a Mars rover is impractical, as the round trip communication time between Earth and Mars ranges from 8 to 42 minutes and the <a href="/facts/Deep_Space_Network/IcapMQTR">Deep Space Network</a> system is only available a few times during each Martian day (<a href="/facts/Timekeeping_on_Mars/kgbNvgkK">sol</a>).<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> Therefore, a rover command team plans, then sends, a sol of operational commands to the rover at one time.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> </p><p>A rover uses <a href="/facts/Autonomy/5ne4C7N8">autonomy</a> <a href="/facts/Computer_software/RP79lVSW">software</a> to make decisions based on observations from its sensors.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> Each pair of stereo images for the <i><a href="/facts/Mars_Pathfinder/frq9TKut">Sojourner</a></i> rover could generate 20 3D navigation points. The <a href="/facts/Mars_Exploration_Rover/74WxIsHS">Mars Exploration Rovers</a> can generate 15,000 (nominal) to 40,000 (survey mode) 3D points.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> </p> <h2 id="performance-comparisons">Performance comparisons</h2> <p>With the exception of <i><a href="/facts/Curiosity_rover/mVLawAfA">Curiosity</a></i> and <i><a href="/facts/Perseverance_rover/NFoubTKJ">Perseverance</a></i>, each Mars rover has had only one on-board computer. Both <i>Curiosity</i> and <i>Perseverance</i> have two identical computers for redundancy. <i>Curiosity</i> is, as of February 2013, operating on its redundant computer, while its primary computer is being investigated for signs of failure.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>[<i>needs update</i>] </p> Comparison of embedded computer systems on board the Mars rovers<table><tbody><tr><th>Landingyear</th><th>Rover (mission, organization)</th><th><a href="/facts/Central_processing_unit/Jxp1bqMV">CPUs</a></th><th><a href="/facts/Random_access_memory/DuD4bxh6">RAM</a></th><th><a href="/facts/Flash_memory/Cn8JsStx">Flash</a></th><th><a href="/facts/EEPROM/0yAMFY0I">EEPROM</a></th><th><a href="/facts/Operating_system/8XTuvMh2">Operating system</a></th><th><a href="/facts/CPU_time/BhzkBzFl">CPU time</a> available for the autonomy software</th></tr><tr><td>1997</td><td><a href="/facts/Sojourner_(rover)/4aN9KJHz"><i>Sojourner</i> rover</a> (<a href="/facts/Pathfinder_mission/frq9TKut">Pathfinder</a>, NASA)<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a><a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a><a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a><a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a></td><td>2 MHz 8-bit <a href="/facts/Intel_80C85/jXpfJnM4">Intel 80C85</a><a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a></td><td>0.5 <a href="/facts/Megabyte/RBF4XpWb">MB</a></td><td>0.172 MB</td><td>None</td><td>Custom <a href="/facts/Cyclic_executive/vGX01J2X">cyclic executive</a></td><td>Not applicable to Cyclic Executives</td></tr><tr><td>1997</td><td><a href="/facts/Pathfinder_mission/frq9TKut">Pathfinder Lander</a> (NASA)<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> (Base station for <i>Sojourner</i> rover) </td><td>20 MHz MFC</td><td>128 MB</td><td>None</td><td>6 MB</td><td><a href="/facts/VxWorks/DCajjp0d">VxWorks</a> (<a href="/facts/Computer_multitasking/Q4acPNMv">multitasking</a>)<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a></td><td>less than 75%</td></tr><tr><td>2004</td><td><a href="/facts/Spirit_(rover)/qNWFPqzj"><i>Spirit</i></a> and <a href="/facts/Opportunity_(rover)/MEC0VIuy"><i>Opportunity</i></a> (<a href="/facts/Mars_Exploration_Rover/74WxIsHS">Mars Exploration Rover</a> (MER), NASA)<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a></td><td>20 MHz 32-bit <a href="/facts/RAD6000/vF1avWxE">BAE RAD6000</a> (<a href="/facts/PowerPC/DqmM9y50">PowerPC</a>)</td><td>128 MB</td><td>256 MB</td><td>3 MB</td><td>VxWorks (multitasking)</td><td>less than 75%</td></tr><tr><td>2012</td><td><a href="/facts/Curiosity_rover/mVLawAfA"><i>Curiosity</i></a> (<a href="/facts/Mars_Science_Laboratory/yEARUMpM">Mars Science Laboratory</a> (MSL), NASA)<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a><a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a><a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a></td><td>200 MHz 32-bit <a href="/facts/RAD750/eRMeuSj2">BAE RAD750</a> (PowerPC)</td><td>256 MB</td><td>2048 MB</td><td>0.25 MB</td><td>VxWorks (multitasking)</td><td>less than 75%</td></tr><tr><td>2021</td><td><a href="/facts/Perseverance_(rover)/NFoubTKJ"><i>Perseverance</i></a> (<a href="/facts/Mars_2020/B6GRHvKH">Mars 2020</a>, NASA)<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a></td><td>200 MHz 32-bit BAE RAD750 (PowerPC)</td><td>256 MB</td><td>2048 MB</td><td>0.25 MB</td><td>VxWorks (multitasking)<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a></td><td>?</td></tr></tbody></table> <h2 id="mars-rovers">Mars rovers</h2> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Radiation_hardening/nB4Wbctl">Radiation hardening</a></li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="http://www.cpushack.com/space-craft-cpu.html">The CPUs of Spacecraft Computers in Space</a></li> <li><a href="https://web.archive.org/web/20221017125626/https://www.baesystems.com/en-media/uploadFile/20211206201500/1434554723601.pdf">Radiation‑hardened electronics product guide</a> - BAE Systems</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>"Computer Swap on Curiosity Rover". NASA/JPL. February 28, 2013. Retrieved June 12, 2017. <a href="https://www.nasa.gov/mission_pages/msl/news/msl20130228.html" target="_blank">https://www.nasa.gov/mission_pages/msl/news/msl20130228.html</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Mars Pathfinder Frequently Asked Questions: Sojourner Rover". NASA/JPL. April 10, 1997. Retrieved March 27, 2009. <a href="https://mars.jpl.nasa.gov/MPF/rover/faqs_sojourner.html" target="_blank">https://mars.jpl.nasa.gov/MPF/rover/faqs_sojourner.html</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Donna L. Shirley and Jacob R. Matijevic (May 10, 1997). "Mars Rovers: Past, Present, & Future". NASA/JPL. Retrieved April 18, 2009. <a href="https://mars.jpl.nasa.gov/MPF/rovercom/data/ROV_PAST.TXT" target="_blank">https://mars.jpl.nasa.gov/MPF/rovercom/data/ROV_PAST.TXT</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Larry Lange (February 18, 1998). "U.S. plays catch-up as robots crawl into new applications". EETimes.com. Retrieved April 18, 2009. <a href="http://www.eetimes.com/news/98/994news/robots.html/" target="_blank">http://www.eetimes.com/news/98/994news/robots.html/</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Mars Pathfinder Frequently Asked Questions <a href="https://mars.jpl.nasa.gov/MPF/rover/faqs_sojourner.html#cpu" target="_blank">https://mars.jpl.nasa.gov/MPF/rover/faqs_sojourner.html#cpu</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>"Wind River Powers Mars Exploration Rovers—Continues Legacy as Technology Provider for NASA's Space Exploration". Wind River. June 6, 2003. Retrieved August 28, 2009. <a href="https://www.windriver.com/news/press/news-314" target="_blank">https://www.windriver.com/news/press/news-314</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Max Bajracharya, Mark W. Maimone, 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. <a href="/wiki/Jet_Propulsion_Laboratory" target="_blank">/wiki/Jet_Propulsion_Laboratory</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>"Mars Science Laboratory: Mission: Rover: Brains". NASA/JPL. Retrieved March 27, 2009. <a href="https://marsprogram.jpl.nasa.gov/msl/mission/rover/brains/" target="_blank">https://marsprogram.jpl.nasa.gov/msl/mission/rover/brains/</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>"BAE SYSTEMS COMPUTERS TO MANAGE DATA PROCESSING AND COMMAND FOR UPCOMING SATELLITE MISSIONS". BAE Systems. June 17, 2008. Retrieved November 17, 2008. <a href="http://www.baesystems.com/Newsroom/NewsReleases/autoGen_108517143749.html" target="_blank">http://www.baesystems.com/Newsroom/NewsReleases/autoGen_108517143749.html</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>mars.nasa.gov. "Brains - Mars 2020 Rover". mars.nasa.gov. Retrieved November 29, 2017. <a href="https://mars.nasa.gov/mars2020/mission/rover/brains/" target="_blank">https://mars.nasa.gov/mars2020/mission/rover/brains/</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>"Prototyping an Onboard Scheduler for the Mars 2020 Rover" (PDF). <a href="https://ai.jpl.nasa.gov/public/documents/papers/rabideau_iwpss2017_prototyping.pdf" target="_blank">https://ai.jpl.nasa.gov/public/documents/papers/rabideau_iwpss2017_prototyping.pdf</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> </ol>