Size comparison of the Mars Exploration Rover (rear) and the Sojourner rover
The embedded computer systems onboard Mars rovers are designed to withstand 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]
Direct teleoperation of a Mars rover is impractical, as the round trip communication time between Earth and Mars ranges from 8 to 42 minutes and the Deep 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 uses autonomy software to make decisions based on observations from its sensors.[1] Each pair of stereo images for the Sojourner rover could generate 20 3D navigation points. The Mars Exploration Rovers can generate 15,000 (nominal) to 40,000 (survey mode) 3D points.[1]
With the exception of Curiosity and Perseverance, each Mars rover has had only one on-board computer. Both Curiosity and Perseverance 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-bit Intel 80C85[6] | 0.5 MB | 0.172 MB | None | Custom cyclic executive | Not applicable to Cyclic Executives |
| 1997 | Pathfinder Lander (NASA)[1] (Base station for Sojourner rover) |
20 MHz MFC | 128 MB | None | 6 MB | VxWorks (multitasking)[7] | less than 75% |
| 2004 | Spirit and Opportunity (Mars Exploration Rover (MER), NASA)[1] | 20 MHz 32-bit BAE 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-bit BAE 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] | ? |
|
| ||
|---|---|---|
| Past missions |
|
|
| Current missions |
| |
| Planned missions |
| |
| Related |
| |
Missions are ordered by launch date. Sign † indicates failure en route or before intended mission data returned. | ||
|
| ||
|---|---|---|
| Mars Pathfinder (Carl Sagan Memorial Station) |
|
|
| Mars Pathfinder instruments |
| |
| Key personnel |
| |
| Related |
| |
|
| ||
|---|---|---|
| General |
|
|
| Spirit rover |
| |
| Opportunity rover |
| |
| Instruments |
| |
| Related |
| |
|
| ||
|---|---|---|
| General |
|
|
| Instruments |
| |
| Features |
| |
| Sites |
| |
| Rocks |
| |
| Related |
| |
| ||
