CAPE CANAVERAL, Fla. -- The Atlas V rocket set to launch NASA's Mars Science Laboratory (MSL) mission is illuminated inside the Vertical Integration Facility at Space Launch Complex 41, where employees have gathered to hoist the spacecraft's multi-mission radioisotope thermoelectric generator (MMRTG). The MMRTG will be lifted up to the top of the rocket and installed on the MSL spacecraft, encapsulated within the payload fairing. The MMRTG will generate the power needed for the mission from the natural decay of plutonium-238, a non-weapons-grade form of the radioisotope. Heat emitted by this natural decay will provide constant power through the day and night during all seasons. MSL's components include a car-sized rover, Curiosity, which has 10 science instruments designed to search for signs of life, including methane, and help determine if the gas is from a biological or geological source. Heat emitted by the MMRTG will be circulated throughout the rover system to keep instruments, computers, mechanical devices and communications systems within their operating temperature ranges. Launch of MSL aboard a United Launch Alliance Atlas V rocket is targeted for Nov. 25 from Space Launch Complex 41 on Cape Canaveral Air Force Station.