London, Nov 18 : With growing concerns about the safety of a nuclear powered mission to Mars, a research team has suggested that solar energy may be a viable alternative, and would supply all the power a Martian colony would need.
Vocal protests accompanied the launch of the deep-space probes Cassini, Galileo and New Horizons, which all contained nuclear power generators, with anti-nuclear groups saying any disaster could rain radioactive debris on Earth.
Off-planet colonies powered with fission reactors are likely to raise similar concerns.
The question is whether solar power can generate the 100 kilowatts that Martian explorers will need to power their life-support systems and to make the fuel needed for the journey back to Earth.
According to a report in New Scientist, to find out an answer to this question, NASA commissioned a study by energy specialists from the Massachusetts Institute of Technology (MIT).
It was generally thought that the sun's rays would be too weak on Mars to supply a significant amount of energy.
However, the MIT team concludes that with a careful choice of location, solar energy can provide all the power a colony would need - even in the teeth of the Red Planet's infamous dust storms.
The team assessed 13 energy-generation systems, comparing nuclear fission reactors, solar arrays that track the sun, non-tracking thin-film solar arrays laid on the Martian surface, and radioisotope thermal generators (RTGs), which use a decaying chunk of radioisotope to create heat that is used to generate electricity.
The MIT team's main aim, according to MIT engineer Wilfried Hofstetter, was to ensure that astronauts squeeze the most power from every kilogram of energy-generating equipment they take to Mars, but always have adequate back-up too.
While nuclear is the clear winner because it can produce a constant supply of power, a large solar array with fuel cells to store power matches its performance, but only if it is sited at a latitude between 0 and 40 degrees north of the Martian equator.
"Southern latitudes have much less solar energy available most of the year," said Hofstetter.
Assuming a mission can take several 2-metre-wide rolls of thin-film solar panel material to Mars, a 100-metre by 100-metre surface array would provide the 100 kilowatts needed at 25 degrees north.
According to the team's calculations, it would take two crew members 17 hours to lay out the array and get it working, though robotic rollout is also a possibility.