|On the drawing board, another nuclear-powered rover (Image: NASA)
A nuclear power source is likely to sustain NASA's next exploration of Mars - a robot that will take a package of samples for return to Earth and address gaps in the knowledge required for manned exploration.
The US space agency NASA released documents on its future plans to continue exploring the surface of Mars, dubbed '2020 Launch'. They are centred on a mobile laboratory similar to the successful Curiosity rover, which landed in August 2012 and has already confirmed that liquid water once flowed on the planet's surface.
The power source envisaged for the future rover is NASA's Multi-Mission Radioisotope Thermal Generator, the same model as used in Curiosity.
NASA's Multi-Mission Radioisotope Thermal Generator uses solid state thermocouples to produce electricity from the steady decay heat coming from 4.8 kg of ceramic plutonium-238 oxide. Several of these modular power units could be combined to provide larger amounts of reliable power for future missions. It includes eight individually packed and shielded plutonium heat sources and weighs 48 kg in total. Providing 110-115 W of continuous power, it gives generates 2.7 kWh per day - far in excess of the maximum 1 kWh per day maximum of previous solar rovers
The forthcoming rover would advance NASA's Mars objectives in a number of ways. Most significantly it would assemble a cache of rock samples that would be searched for 'biosignatures' - remnants of ancient lifeforms or conclusive signs of their existence. The rover would have to interact with a subsequent mission that would convey the suitably sealed cache back to Earth for detailed examination and the potential discovery.
In support of future manned missions the rover would gather geologic data to inform research on the possibility of extracting resources. It would also survey radiation levels on the Martian surface.
Readings from Curiosity showed that background radiation on Mars rises and falls in a cycle linked to atmospheric pressure. The levels are not too high for habitation, but astronauts are currently bound by 'career limits' for radiation exposure which could be challenged by the significantly higher levels of radiation found during 34-week trips to and from the planet.
Researched and written
by World Nuclear News