Comparison of embedded computer systems on board the Mars rovers
Encyclopedia
The embedded
computer systems that are on board the various Mars rover
s 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.
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). Because of this a command team for the rover will plan an entire sol worth of operations and then send it to the rover.
software
to make decisions based on the observations from its sensors. 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.
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
computer systems that are on board the various Mars rover
Mars Rover
A Mars rover is an automated motor vehicle which propels itself across the surface of the planet Mars after landing.Rovers have several advantages over stationary landers: they examine more territory, they can be directed to interesting features, they can place themselves in sunny positions to...
s sent to Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
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.
Operation issues
Direct teleoperationTeleoperation
Teleoperation indicates operation of a machine at a distance. It is similar in meaning to the phrase "remote control" but is usually encountered in research, academic and technical environments...
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
Deep Space Network
The Deep Space Network, or DSN, is a world-wide network of large antennas and communication facilities that supports interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected...
system is only available for use a few times during each Martian day (sol). Because of this a command team for the rover will plan an entire sol worth of operations and then send it to the rover.
Autonomy software
A rover uses autonomyAutonomy
Autonomy is a concept found in moral, political and bioethical philosophy. Within these contexts, it is the capacity of a rational individual to make an informed, un-coerced decision...
software
Computer software
Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....
to make decisions based on the observations from its sensors. 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
Mars Exploration Rover
NASA's Mars Exploration Rover Mission is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars...
rovers can generate 15,000 to 40,000 3D points.
Performance comparisons
| Rover (mission, organization, year) | CPU Central processing unit The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in... | RAM | Flash Flash memory Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data... solid state storage | Operating system Operating system An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system... | CPU time CPU time CPU time is the amount of time for which a central processing unit was used for processing instructions of a computer program, as opposed to, for example, waiting for input/output operations. The CPU time is often measured in clock ticks or as a percentage of the CPU's capacity... available for the autonomy software |
|---|---|---|---|---|---|
| Sojourner Rover (Pathfinder, NASA, 1997) | 100 kHz Intel 80C85 | 512 KB Kilobyte The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information... |
176 KB | Custom cyclic executive Cyclic executive A cyclic executive is an alternative to a real-time operating system. It is a form of cooperative multitasking, in which there is only one task. The sole task is typically realized as an infinite loop in main, e.g. in C/C++.... |
Currently unavailable |
| Pathfinder Lander (NASA, 1997) | 20 MHz MFC (IBM RAD6000 RAD6000 The RAD6000 radiation-hardened single board computer, based on the IBM RISC Single Chip CPU, was manufactured by IBM Federal Systems. IBM Federal Systems was sold to Loral, and by way of acquisition, ended up with Lockheed Martin and is currently a part of BAE Systems... Precursor) |
128 MB Megabyte The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000... |
6 MB (EEPROM) | VxWorks VxWorks VxWorks is a real-time operating system developed as proprietary software by Wind River Systems of Alameda, California, USA. First released in 1987, VxWorks is designed for use in embedded systems.- History :... (multitasking Computer multitasking In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for... ) |
less than 75% |
| Spirit and Opportunity (Mars Exploration Rover Mars Exploration Rover NASA's Mars Exploration Rover Mission is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars... (MER), NASA, 2004) |
20 MHz IBM RAD6000 RAD6000 The RAD6000 radiation-hardened single board computer, based on the IBM RISC Single Chip CPU, was manufactured by IBM Federal Systems. IBM Federal Systems was sold to Loral, and by way of acquisition, ended up with Lockheed Martin and is currently a part of BAE Systems... |
128 MB Megabyte The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000... |
256 MB | VxWorks (multitasking) | less than 75% |
| Curiosity (Mars Science Laboratory Mars Science Laboratory The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012... (MSL), NASA, 2011) |
200 MHz IBM RAD750 RAD750 The RAD750 is a radiation-hardened single board computer, based on IBM's PowerPC 750. The successor of the RAD6000, the RAD750 is manufactured by BAE Systems Electronic Solutions. It is intended for use in high radiation environments such as experienced on board satellites and spacecraft... |
256 MB | 2 GB Gigabyte The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is... |
VxWorks (multitasking) | less than 75% |