May 7, 2009

NASA Running Out Of Plutonium

NASA reported on Thursday that the nuclear fuel needed for its deep space exploration missions is running out, The Associated Press reported.

The new study by the U.S. space agency said it does not have enough plutonium for future faraway space probes "” except for a few missions already scheduled.

The lack of plutonium stems from the end of the Cold War's nuclear weapons buildup.

A specific type of the radioactive element, plutonium-238, is required to power deep space probes beyond Jupiter, as they are too far away from the sun to run off solar power. Such spacecraft are powered with the heat of plutonium's natural decay. 

However, plutonium-238 is a byproduct of nuclear weaponry that can't be found in nature.

NASA had been acquiring sources of the plutonium from Russia, as the U.S. stopped making it about 20 years ago. The Russian supply, however, is also dwindling after the country also decided to stop producing it.

A spokeswoman for The Department of Energy announced on Thursday that it would restart its program to make plutonium-238.

The agency has proposed $30 million in next year's budget for preliminary design and engineering. The National Academy's study shows why it is needed, spokeswoman Jen Stutsman said.

Johns Hopkins University senior scientist Ralph McNutt, who has had experiments aboard several of NASA's deep space missions, said without the specific material they would no longer be able to do deep space missions.

Doug Allen, a satellite power expert and member of the National Academy's study panel, warned that since NASA is the only agency that undertakes such missions, the shortage limits the world's look at deep space.

The Department of Energy is authorized by law to make the plutonium.

In 2008, NASA administrator Michael Griffin wrote to then-Energy Secretary Samuel Bodman that the agency needed more plutonium for future missions.

The Energy Department would have to spend at least $150 million to resume making the 11 pounds of plutonium a year that NASA needs for its space probes, according to The National Academy report.

McNutt said without that material a lot of things would be shut down and they would stay shut down for a long time.

The over-budget and delayed Mars Science Laboratory, set to launch in 2011, and a mission to tour the solar system's outer planets scheduled for launch in 2020, are two upcoming NASA missions that would require the use of plutonium.

The New Horizons probe headed for Pluto and the Cassini space probe that is circling Saturn are the last two missions to use the element.

McNutt said plutonium-powered probes are capable of running for a very long time. For instance, the twin Voyager spacecraft launched in 1977 that are headed beyond our solar system are expected to keep working until at least 2020.

Both McNutt and Allen acknowledged that solar power is preferable to plutonium because it is cheaper and has fewer safety concerns.

However, solar power just doesn't work in the darkest areas of space, including deep craters of the moon.

Many experts have expressed concern and even protested past nuclear-powered missions, arguing they are ripe for potential accidents.


Image Caption: Mars Science Laboratory Concept


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