Theembeddedcomputer systems onboardMars rovers are designed towithstand high radiation levels and large temperature changes in space. For this reason their computational resources are limited compared to systems commonly used on Earth.[1]
Directteleoperation of a Mars rover is impractical, as the round trip communication time between Earth and Mars ranges from 8 to 42 minutes and theDeep Space Network system is only available a few times during each Martian day (sol).[1] Therefore, a rover command team plans, then sends, a sol of operational commands to the rover at one time.[1]
A rover usesautonomysoftware to make decisions based on observations from its sensors.[1] Each pair of stereo images for theSojourner rover could generate 20 3D navigation points. TheMars Exploration Rovers can generate 15,000 (nominal) to 40,000 (survey mode) 3D points.[1]
With the exception ofCuriosity andPerseverance, each Mars rover has had only one on-board computer. BothCuriosity andPerseverance have two identical computers for redundancy.Curiosity is, as of February 2013, operating on its redundant computer, while its primary computer is being investigated for signs of failure.[2][needs update]
| Landing year | Rover (mission, organization) | CPUs | RAM | Flash | EEPROM | Operating system | CPU time available for the autonomy software |
|---|---|---|---|---|---|---|---|
| 1997 | Sojourner rover (Pathfinder, NASA)[1][3][4][5] | 2 MHz 8-bitIntel 80C85[6] | 0.5MB | 0.172 MB | None | Customcyclic executive | Not applicable to Cyclic Executives |
| 1997 | Pathfinder Lander (NASA)[1] (Base station forSojourner rover) | 20 MHz MFC | 128 MB | None | 6 MB | VxWorks (multitasking)[7] | less than 75% |
| 2004 | Spirit andOpportunity (Mars Exploration Rover (MER), NASA)[1] | 20 MHz 32-bitBAE RAD6000 (PowerPC) | 128 MB | 256 MB | 3 MB | VxWorks (multitasking) | less than 75% |
| 2012 | Curiosity (Mars Science Laboratory (MSL), NASA)[1][8][9] | 200 MHz 32-bitBAE RAD750 (PowerPC) | 256 MB | 2048 MB | 0.25 MB | VxWorks (multitasking) | less than 75% |
| 2021 | Perseverance (Mars 2020, NASA)[10] | 200 MHz 32-bit BAE RAD750 (PowerPC) | 256 MB | 2048 MB | 0.25 MB | VxWorks (multitasking)[11] | ? |