Fridge being designed to keep Venus Rover cool

A high-tech refrigeration system is being designed to keep a rover functioning for weeks on the searingly hot surface of Venus, claim NASA researchers.

Washington, Nov.13 : A high-tech refrigeration system is being designed to keep a rover functioning for weeks on the searingly hot surface of Venus, claim NASA researchers.

According to Geoffrey Landis and Kenneth Mellott of NASA's Glenn Research Center in Cleveland, Ohio, the long-lived Venus rover could help scientists understand why Venus, with its runaway greenhouse effect, has become so different from Earth.

The surface of Venus broils at a temperature of about 450 degree celsius - hot enough to melt lead. Several probes in the Soviet Venera and Vega series, as well as a NASA Pioneer Venus probe, landed on Venus and returned data from the surface in the 1970s and early 1980s. But they all expired in less than two hours because of the tremendous heat.

Landis and Mellot have designed a refrigeration system that might be able to keep a robotic rover going for as long as 50 Earth days.

Their main concern is keeping the electronics cool, and they plan to do this by packing the electronics in a ceramic-based insulator and placing it inside a metal sphere about the size of a grapefruit.

Heat would then be pumped out of the sphere using a Stirling cooler, which works by compressing and then expanding a gas with a piston. When the gas expands, it cools down, absorbing heat from the electronics chamber.

Then, as the gas is compressed and its temperature rises, the heat is allowed to dissipate in the atmosphere via a radiator.

Using a Stirling cooler, Landis and Mellott have designed one suitable for use in the incredibly hot environment of Venus.

The researchers say the power to run the Stirling cooler, about 240 watts, would be provided by on-board plutonium batteries, which generate power from the heat of radioactive decay.

"The next step is probably going to be trying to build some prototypes and just demonstrate that what we are proposing is something that's going to work," Landis said.

NASA has not committed to a Venus rover mission, but Landis notes that a 2003 National Academies of Science study recommended that high priority be given to a robot mission to investigate the Venusian surface.

Landis thinks a Venus rover could become a reality within a decade or so.

ANI