On 6 August, NASA’s Mars Science Laboratory spacecraft, launched at the end of November last year, will deliver a car-sized rover called Curiosity to the surface of Mars to begin a two-year prime mission. Its job – to investigate whether the selected area of Mars offers environmental conditions favourable for microbial life, or whether there’s any evidence that life once existed on the Red Planet. For the record, this is a big deal.
Curiosity. It’s a good name for a Mars rover, especially one as large – it’s about twice the length and five times the weight of NASA’s twin rovers, Spirit and Opportunity – and formidably equipped as this machine.
It inherited many design elements from the earlier rovers, including six-wheel drive, a rocker-bogie suspension system, and cameras mounted on a mast to help the mission’s team on Earth select exploration targets and driving routes. Unlike its predecessors, however, Curiosity carries equipment that will enable it to gather samples of rocks and soil, process and distribute them to on-board test chambers inside analytical instruments.
An instrument named ChemCam will use laser pulses to vaporise thin layers of material from Martian rocks or soil targets up to 9 m away. It will include both a spectrometer to identify the types of atoms excited by the beam, and a telescope to capture detailed images of the area illuminated by the beam. The laser and telescope sit on the rover’s mast and share with the Mast Camera the role of informing researchers’ choices about which objects in the area make the best targets for further examination. The mission will use radio relays via Mars orbiters as the principal means of communication between Curiosity and the Deep Space Network of antennas on Earth.
Electrical power will be supplied by a radioisotope power generator, a canny piece of kit that produces electricity from the heat of plutonium-238’s radioactive decay. This long-lived power supply gives the mission an operating lifespan of a full Mars year (687 Earth days) or more. At launch, the generator will provide about 110 watts of power to operate the rover’s instruments, robotic arm, wheels, computers and radio. Warm fluids heated by the generator’s excess heat are plumbed throughout the rover to keep electronics and other systems at acceptable operating temperatures.
Curiosity‘s landing site is near the base of a mountain inside Gale Crater, near the Martian equator. In the 23 months following its descent to the Martian surface, Curiosity will analyse dozens of samples drilled from rocks or scooped from the ground. This rover can really go places: NASA’s Jet Propulsion Laboratory has engineered it to roll over obstacles up to 65 cm high and to travel up to about 200 m a day on Martian terrain.
NASA announced last month that the rover would touch down even closer to the mountain slope. Said Pete Theisinger, Mars Science Laboratory project manager at NASA’s Jet Propulsion Laboratory: “We’re trimming the distance we’ll have to drive after landing by almost half. That could get us to the mountain months earlier.”