NASA may put nuclear energy on the moon
Nuclear energy has long been used as a power source on earth. Efforts to replace foreign-sourced fuels mean that U.S. energy policy continues to see nuclear initiatives as part of the power generating mix.
Now NASA and the Department of Energy are testing technology that may let scientists build a nuclear fission reactor – viewed as the most mass-efficient electricity supply for a future lunar or Mars outpost. NASA is aiming to send humans back to the moon in the decade beginning 2020, while Mars surface exploration is planned for the following decade.
“We’re only looking for 40 kilowatts, the equivalent energy of powering about eight houses in the United States,” he says. “That’s a lot of power on the moon.”
According to NASA, the fission surface power system could use a small nuclear reactor, about the size of an office trash can, to fuel Stirling power generators. The electricity produced could be used for life support, performing experiments, recharging rovers and mining resources.
“We feel very strongly that we owe it to future explorers to provide reliable power,” Palac says. “We don’t want to have them end up like the folks on Apollo 13 searching for that last amp of power.”
Nuclear power is an option for potential lunar and Mars bases because of the expectation that reliable and steady power will be necessary. Robust equipment that stands up to extremely cold temperatures and dust storms in space is imperative – and the costs have to be controlled.
The current plans are far beyond the U.S. space program’s last foray into nuclear power for use in space: the SNAP 10A program of the 1960s which generated power in the 100 watt range, enough for a light bulb. According to NASA, the most recent tests generated more than 2 kilowatts of electricity.
“Our biggest challenge is that a fundamental tenet going into the project is it has to be affordable,” Palac says. “We can’t impose upon the exploration infrastructure; it is very tight on money. We had to prove and demonstrate affordability with a cost estimate based on a concept we developed.”
According to Palac, the knowledge that nuclear power has a high energy density – a little bit of nuclear power goes a long way – is key to its consideration as an option for powering lunar and Mars outposts.
“But how do you demonstrate an affordable system would work in the environment of planetary surfaces? That is the specific challenge,” he says.
Three separate parts of the project recently have undergone tests that have scientists positive about the progress being made:
- a lightweight composite radiator panel was successfully tested in a vacuum chamber at Glenn that replicates the hard vacuum and extreme cold temperatures, close to -200 degrees Fahrenheit. The radiator, approximately 6 feet by 9 feet, is a prototype for one of 20 panels scientists project would be needed to cool a power system on the lunar surface.
- at NASA’s Marshall Space Flight Center in Huntsville, Ala., Stirling engines were heated with a pumped liquid metal, replicating how heat could be delivered from a reactor to the converter – a step in the process to demonstrate the technical feasibility of fission surface power.
- at Sandia National Laboratories in Albuquerque, NM, a Stirling alternator was operated during exposure to radiation levels similar to those from a reactor. There was no change in electrical power input required to maintain alternator operation, which would have been a possible indication of radiation damage.
“The pace of progress exhibited by these three achievements in the same time period is exciting,” Lee Mason, Glenn’s principal investigator for the fission surface power project, said in an August 2009 statement. “It has built the team’s confidence and prepared them for challenges that lay ahead.”
The next major step is a non-nuclear system level technology demonstration where all of the major elements will be combined in one test. This test is scheduled to begin in 2012 and at current budget levels could be complete by 2014, which is in step with the lunar surface program’s schedule.
“Depending on when they want the power, we’re preserving the option for a 2021 deployment,” Palac says.