Cooling off: Marc Gibson, a NASA test engineer, inspects the radiator panel used to cool the fission power system that is being tested at Glenn Research Center. The panel is six feet by nine feet. Twenty such radiators would be needed for a full-scale system.
The researchers also developed a lightweight radiator panel to cool the system and dissipate the heat from the reactor. The prototype panel is approximately six feet by nine feet–one-twentieth the size required for a full-scale system. Heat from a water-cooling system is circulated to the radiator where it dissipates.
The researchers tested the radiator panel in a vacuum chamber at Glenn that replicates the lack of atmosphere and the extreme temperatures on the moon–from over 100 degrees Celsius during the day to below 100 degrees Celsius at night. The panel dissipated six kilowatts of energy, more than expected–a “very successfully test,” says Palac. On the moon, the panel must also survive the dusty environment cause by the regolith.
Lastly, the researchers tested the performance of the Stirling alternator in a radiation environment at Sandia National Laboratories in Albuquerque, NM. The objective was to test the performance of the motor, ensuring that the materials would not degrade. The alternator was subjected to 20 times the amount of radiation it would expect to see in its lifetime and survived without any significant problems.
Mason says that the tests are very important in showing the feasibility of the system and that the next step is for the researchers to conduct a full system demonstration, by combining a non-nuclear reactor simulator with the Stirling engine and radiator panel. He says that these tests should be completed in 2014.
The researchers are also working on the power transmission and electronics of the system. “A lunar base needs lots of power for things like computers, life support, and to heat up rocks to get out resources like oxygen and hydrogen,” says Ross Radel, a senior member of the technical staff and part of the advanced nuclear concepts group at Sandia. His group is working on the systems dynamic analysis, a computer model that predicts how the reactor will perform during testing. “Nuclear is a stepping stone to move further out into manned space exploration,” says Radel.
“It is a fascinating project and the only possible method of providing power for a manned trip to Mars,” says Daniel Hollenbach, a researcher in the nuclear science and technology division at Oak Ridge National Laboratory, who was not involved in the project.
Mason says that nuclear fission is one of a number of concepts being tested as a power source for human missions to the moon and Mars, and if selected, he says the technology could be deployed by 2020.