updated 09:26 pm EDT, Mon August 6, 2012
Number of MacBook Pros at JPL, descendant of G3 on Curiosity
NASA's widely-watched Curiosity rover landing on Mars, which touched down at 1:31 Eastern Standard Time Monday morning, had numerous connections to Apple technologies. From the prominent display of MacBook Pros in the control room to the rover itself (sporting a pair of G3-era processors), the space agency is much more visibly using technology associated with Apple now.
The rover itself has a variant of the IBM-designed, Motorola-made PowerPC chip as its core processor. The PPC 750 family was found in every G3-powered machine, all the way from the first Bondi Blue iMac to the end of the line iBook G3. The Curiosity rover is powered by a pair of radiation-hardened BAE-produced RAD 750 processors. The chips on the space mission have a larger environmental tolerance than desktop chips, as one would expect from a space-capable processor.
The single-board system (CPU and motherboard combination) can withstand up to 100,000 rad (1,000 gray). For perspective, a radiation worker's annual limits as set by federal law are five rem (generally equivalent to a rad, under most conditions) per year, not to exceed three rem per calendar quarter. A worker receiving a single dose of 100 rem over a short period of time will start to exhibit signs of radiation sickness. United States citizens receive approximately 0.36 rem of exposure per year from naturally-occurring radiation sources. Apollo astronauts received a dose of approximately 0.5 rem during their flights, which would be more inline with what one would expect the Curiosity rover to receive over a 10-day span in space. Martian background radiation is much higher than the Earth's, at approximately 50 rad of exposure per year. Modern processors such as the Sandy or Ivy Bridge Intel chips are expected to exhibit major calculational errors after just 100 rad of cumulative exposure.
The hardened processor was first installed on the Deep Impact comet-chasing craft, and will be launched on the Titan Saturn System Mission in 2020. There have been over 150 RAD750 processors installed in a number of spacecraft from different nations since the radiation-resistant one was released in 2004.
The Apple links don't stop on the rover. In live-streamed video from Jet Propulsion Laboratory in Pasadena, a bevy of engineers and scientists monitoring the rover's process sat huddled around their computers -- mostly MacBook Pro 15-inch models. While not readable, the bar-code sticker on the lid of the units signify the machines as US Government property, according to sources contacted by MacNN. None of the computers with visible displays appeared to be running Windows or Linux.