A Mac On Mars?
WALL-E was a Mac, but he never went to Mars. You know he was a Mac by the famous startup chime you hear when he is fully recharged. Unlike WALL-E, NASA's Curiosity rover did indeed make it to Mars, and it just so happens, uses a PowerPC processor based on the original iMac's processor. The PowerPC was developed by an alliance between Apple, IBM, and Motorola. Many Macs featured PowerPC processors until Apple switched to Intel processors in 2005.
For good reason, many automatically think "Mac" when the PowerPC is mentioned. The original iMac's processor was the PowerPC 750 . Curiosity uses a radiation-hardened PowerPC based on that, called the RAD 750. Unlike the Mac, Curiosity does not run a Mac OS version of any kind. Technically, Curiosity is not really a Mac; So, that famous startup chime will not be heard echoing across the barren scape of the red planet... at least not yet.
Curiosity is still a fascinating machine. It's onboard Operating System is called VxWorks. This realtime OS is also used on other systems such as the Apache Longbow attack helicopter, BMW iDrive, several spacecraft, some printers and routers, and more.
Curiosity is powered by a "nuclear battery", otherwise known as an RTG (Radioisotope Thermoelectric Generator). Basically, it uses a nuclear material and some thermocouples to generate voltage from the temperature difference between the martian cold and the heat from the nuclear material (Plutonium-238). It will generate 110 Watts of continuous electrical power for years.
It communicates with the Mars Orbiters using its UHF Electra radio. But it can also communicate directly to Earth with an X band transmitter and receiver.
Curiosity recently received and returned the first "interplanetary voicemail" via the rover's broadcast capabilities. But what would really get the Martian population excited would be to include Siri on the next rover, and let them ask questions in very deliberate and pronounced English. Maybe that's how WALL-E got his start.
 The PowerPC family of processors was not exclusive to Macs. PowerPC architecture has been used by other hardware, such as video game consoles like the Wii, Xbox 360, and Playstation 3.