Spacecraft 'Nuclear Batteries' Could Get a Boost from New Materials
A cutting-edge development in spacecraft power systems is a class of materials with an unfamiliar name: skutterudites (skut-ta-RU-dites). Researchers are studying the use of these advanced materials in a proposed next-generation power system called an eMMRTG, which stands for Enhanced Multi-Mission Radioisotope Thermoelectric Generator. RTGs have enabled many other missions that have sent back a wealth of science results, including NASA's Mars Curiosity rover and the New Horizons mission, which flew by Pluto in 2015. The new eMMRTG would provide 25 percent more power than Curiosity's generator at the start of a mission, according to current analyses. Additionally, since skutterudites naturally degrade more slowly that the current materials in the MMRTG, a spacecraft outfitted with an eMMRTG would have at least 50 percent more power at the end of a 17-year design life than it does today. Read more
World Nuclear News, the information arm of the World Nuclear Association that seeks to boost the use of atomic energy, last week heralded a NASA Mars rover slated to land on Mars on Monday, the first Mars rover fuelled with plutonium. In its July 27 dispatch, World Nuclear News noted that the Mars rover that NASA calls Curiosity and intends to land on August 6, is "powered by a large radioisotope thermal generator instead of solar cells" as previous NASA Mars rovers had been. It is fuelled with 10.6 pounds of plutonium. Read more
NASA feels 'plutonium pinch' earlier than expected
Many spacecraft are powered by the radioactive decay of plutonium-238, but the US no longer produces the material. Instead, NASA relies on its shrinking stockpile, topped up with purchases from Russia. Previous estimates suggested the decline would not affect solar-system exploration until after 2020, but NASA is already tightening its belt. Candidates for NASA's next "New Frontiers" mission, which aims to launch an exploratory spacecraft by 2018, will not be allowed to rely on plutonium for power, effectively limiting the candidate probes to solar power only. Read more
NASA is running out of the special kind of plutonium needed to power deep space probes, worrying planetary scientists who say the U. S. urgently needs to restart production of plutonium-238. But it's unclear whether Congress will provide the $30 million that the administration requested earlier this year for the Department of Energy to get a new program going. Nuclear weapons use plutonium-239, but NASA depends on something quite different: plutonium-238. A marshmallow-sized pellet of plutonium-238, encased in metal, gives off a lot of heat.
For years, the National Aeronautics and Space Administration (NASA) said it couldn’t be done. Beyond the orbit of Mars, NASA said, solar energy could not be used to generate electricity for onboard power on space missions.
So the agency used the extremely dangerous nuclear substance, plutonium, as fuel in electric generating systems—and people on Earth were put at great risk in the event of an accident.
The United States is poised to produce plutonium-238 for the first time since the end of the Cold War but this time it will be used for space missions, not weapons. The U.S. Department of Energy will decide soon whether to move forward with its proposal to produce the radioactive metal at the Idaho National Laboratory a federal nuclear facility in southeast Idaho.
The facility would produce 5 kg of plutonium-238 a year for 30 years starting in 2011. The non-weapons-grade plutonium is used to product "space batteries" to power satellites and deep space probes.
The proposal calls for half the batteries to be earmarked for NASA projects and the rest for undisclosed national security purposes. The United States needs to produce plutonium because its stockpiles are low and because an agreement with Russia prevents it from using plutonium-238 produced there for security or defence applications.
Idaho officials are endorsing the proposal but are in a dispute with the Department of Energy over disposal of radioactive waste. They want written assurances that the estimated 5,500 gallons of contaminated waste generated each year by producing plutonium-238 would be removed from the state.
"In my opinion, this would lay the foundation for Idaho to become a leader in our nation's space program. This could make Idaho a significant part of NASA." - Mike Crapo, U.S. Republican Senator.
Idaho and the Department of Energy have been locked in a years-old conflict over cleanup of nuclear waste materials at the laboratory's sprawling complex near Idaho Falls. The complex overlies the Eastern Snake River Aquifer, one of the state's primary sources of drinking and irrigation water.
"We want to make sure we don't repeat problems of the past that led us to have waste with no clear disposal path" - Kathleen Trever, Idaho Governor.
Defence analysts say the long-lasting, plutonium-powered batteries the Department of Energy wants to produce at a new $300 million facility in Idaho could eventually wind up in everything from space-based satellite killers to battlefield laptop computers.
That's contrary to how the agency says the batteries will be used. But because of the program's classified status, the Bush administration won't say specifically what types of national security programs the batteries are needed for, only what applications they won't be used in: nuclear weapons, non-nuclear weapons, missile defence systems and military satellites.
"The primary driver for us to start production is for national security requirements," said Tim Frazier, director of the energy department's radioisotope power systems program in Washington, D.C. "As to what those national security applications are, I would just prefer to say not in space."
But military and space policy analysts say the radioisotope thermoelectric generators -- sometimes called "space batteries" -- to be made from new supplies of plutonium-238 produced at the Idaho National Laboratory are a key component to future warfare systems, both in the heavens and on earth.
And since the terrorist attacks of Sept. 11, 2001, they argue there's no real distinction between national security and national defence.
"You have to ask, what is national security that is not military?" said John Pike, the former director of space policy for the Federation of American Scientists who now heads the Virginia-based think tank GlobalSecurity.org. "Our government is perfectly capable of lying in the sense that if this is for an unacknowledged stealth satellite system, they could not acknowledge that's what they are doing."
The White House is expected to soon release an updated version of the 1996 doctrine of U.S. military space policy which could relax some Clinton administration-era restrictions on research and budgeting for space weapons programs. And the Strategic Forces Subcommittee of the House Armed Services committee is planning to hold hearings on weapons in space this summer. A Senate panel held similar hearings this spring.
"Few could dispute that our military capability depends on space control," said Senator. Jeff Sessions, R-Ala., chairman of the Senate Armed Services Strategic Forces Subcommittee. "We need to be investing in things that will allow us to continue to have that control and improve our capabilities."
Currently, components of space batteries for peaceful applications such as NASA's mission to Pluto next year are produced at Department of Energy sites in Oak Ridge, Tennessee, and Los Alamos, N.M., with final assembly in Idaho. The NASA batteries use plutonium-238 purchased from Russia, but that supply is considered unreliable and projected to be virtually depleted by 2010.
The use of Russian-made plutonium-238 in national security applications is banned by international agreements.
The plutonium-238 that is available for national security missions was last produced by the DOE in the 1980s in South Carolina and the remaining 55 pounds also is expected to be used up in five years.
The Bush administration wants to spend up to $300 million to consolidate all plutonium-238 production, space battery assembly and testing in a new "Space and Security Power Systems Facility" at the DOE's remote desert compound in eastern Idaho to reduce security risks and avoid interstate transportation of the highly radioactive material. The facility would make 11 pounds of plutonium-238 a year for both national security and space exploration needs.
Space batteries work by converting heat from the radioactive decay of plutonium-238 -- the sister to plutonium-239 used in nuclear weapons -- into electricity. The batteries are considered the best power source for unmanned space vehicles, producing hundreds of watts of electricity for decades. The plutonium batteries aboard the Voyager 1 spacecraft, launched in 1977, were still working at 80 percent capacity when it left the solar system in 2003.
James Lewis, director of the Technology and Public Policy program at the Centre for Strategic and International Studies in Washington, D.C., said plutonium batteries could also be important to the U.S. military, where high-speed computer networks relay data to ground troops.
"It sounds silly, but when you have a very fast mobile force that is heavily dependent on electronic information, one of the military's biggest problems is how to get fresh batteries to the field," said Lewis. "If you found a way for this type of long-lasting battery to be small enough and safe enough for terrestrial use, you've solved a huge logistics problem."
But sending batteries so potentially dangerous -- plutonium-238 is so radioactive even a speck is deadly -- into space or battle worries Peter Rickards. The Idaho podiatrist has rallied opposition to plans to consolidate plutonium-238 battery production in the state.
"Our state politicians are acting like we won a prize with this clustering of a terrorist target in Idaho," said Rickards. "Our next step is to educate as many people as possible that this deadly threat is coming soon to everyone's backyard."