MRO‘s main computer is a 133 MHz, 10.4 million transistor, 32-bit, RAD750 processor. This processor is a radiation-hardened version of a PowerPC 750 or G3 processor with a specially-built motherboard. The RAD750 is a successor to the RAD6000. This processor may seem underpowered in comparison to a modern PC or Mac processor, but it is extremely reliable, resilient, and can function in solar flare-ravaged deep space.[42] The operating system software is VxWorks and has extensive fault protection protocols and monitoring.[43]
Data is stored in a 160 Gb (20 GB) flash memory module consisting of over 700 memory chips, each with a 256 Mbit capacity. This memory capacity is not actually that large considering the amount of data to be acquired; for example, a single image from the HiRISE camera can be as large as 28 Gb.
http://en.wikipedia.org/wiki/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. It is intended for use in high radiation environments such as experienced on board satellites and spacecraft. The RAD750 was released for purchase in 2001; a successor was planned for 2007.
The CPU has 10.4 million CMOS transistors, nearly ten times more than its predecessor. It is manufactured using 250 nm photolithography and has a die area of 130 mm². It has a core clock of 133–166 MHz and can process at up to 300 MIPS, or greater with an extended L2 cache. Its packaging and logic functions are completely compatible with the standard PowerPC 750.
The CPU itself can withstand 2,000 grays and temperature ranges between –55 °C and 125 °C. The standard RAD750 single-board system (CPU and motherboard) can withstand 1,000 grays and temperature ranges between –55 °C and 70 °C and requires at most 5 watts of power.
The RAD750 system has a price tag in excess of US$200,000; the high price is mainly due to the radiation hardening manufacturing process, stringent quality control requirements (MIL-spec), and the small quantity manufactured (integrated circuit manufacturing is optimized for large volume).
There are as of fall 2007 about 10 spacecraft in operation using RAD750 computers.
The Mars Reconnaissance Orbiter spacecraft has a RAD750 on board.
Two RAD750 computers power the WorldView-1 satellite which will provide for high-resolution imaging of Earth. It is a part of the National Geospatial-Intelligence Agency's NextVire programme.
By 2010 there will be about 150 satellites run by a multitude of operators in space using RAD750 computers.
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