Curiosity is a radioisotope-powered rover and part of the NASA Mars Science Laboratory (MSL) mission, whose goal was to deliver Curiosity safely to the Martian surface. Curiosity is the fourth unmanned rover NASA has sent to Mars. Curiosity has far more and more advanced scientific instruments with it than the previous rovers, and will therefore have the opportunity to make far more interesting measurements of the geology and climate on the planet.
Curiosity was launched from Cape Canaveral on November 26, 2011 aboard the MSL spacecraft, and landed on the Aeolis Palus plain in Gale Crater on Mars on August 6, 2012.
Curiosity is about five times as heavy as the previous rovers Spirit and Opportunity, and it carries over ten times as much scientific instruments by mass. The rover is powered by a radioisotope generator powered by 4.8 kg of plutonium(IV) oxide. In the beginning, the generator will produce 125 We. The output will decrease over time as the fuel decays, but even after 14 years it will produce 100 We, and it is likely that other components will fail before that time. It is planned that the rover will last at least one Martian year (687 days on Earth), and that during this time it will examine an area of 5 by 20 km.
The temperature in the area where the rover operates varies between −127 °C and 30 °C. Many components and instruments cannot operate in such a wide temperature range, so the rover has many solutions to adjust the temperature. Among other things, it is equipped with a 60 meter long closed liquid loop that distributes heat between the various components, and this can collect residual heat from the radioisotope generator.
Instruments and analysis
Curiosity uses a high-resolution camera (called "MastCam") to look for formations that look interesting to study further. When the camera finds a potentially interesting surface, an infrared laser is used to vaporize a tiny bit of it—enough so that an atomic emission spectrum can be recorded to determine which elements are present (this instrument is called "ChemCam"). If the signature looks interesting, the rover's long arm will swing out a microscope (MAHLI) and an X-ray spectroscope (APXS) into position to find out more about what kind of rock it might be. Curiosity also has a small drill, which can deliver a powder sample to two analysis stations inside the rover: CheMin and SAM. In CheMin, an X-ray powder diffraction and an X-ray fluorescence instrument can help identify minerals and rocks, while in SAM there is a mass spectrometer, a gas chromatograph and a laser spectrometer to look for organic compounds, among other things.