Navy May Help NASA Build Nuclear Reactor for Jupiter Mission

ALBUQUERQUE, New Mexico – A NASA project to Jupiter and several of its moons may depend on the U.S. Navy to provide the nuclear know-how in building a reactor for deep space exploration.

The Jupiter Icy Moons Orbiter (JIMO) program is a flagship mission under NASA’s Project Prometheus – a multi-pronged effort to develop near- and long-term nuclear electric power and propulsion technologies. JIMO would be powered by a compact nuclear reactor and propelled by a set of ion engines that expel electrically charged particles to generate thrust.

NASA and the scientific community are considering adding a Europa lander to JIMO. The high-tech lander could make on-the-spot surface observations at the Jovian satellite. Europa is thought to harbor an ocean under its icy crust.

NASA as well as industry teams and other government agencies have begun to scope out how to build JIMO. Experts in nuclear-power technology gathered at the Space Technology and Applications International Forum (STAIF), held here February 8-11, to discuss how best to re-energize a nuclear space reactor program.

NASA’s Project Prometheus has the goal of developing a reactor-powered spacecraft. JIMO is being blueprinted to integrate this capability.

Discussions are underway between NASA and Naval Reactors -- located in the Department of Energy’s National Nuclear Security Administration -- to jointly build a space-rated nuclear reactor to be used for JIMO and other deep space missions.

Alan Newhouse, NASA Director of the Project Prometheus, told SPACE.com that high-level talks have been underway to iron out issues regarding Naval Reactors taking on the duties of fabricating a nuclear reactor for space.

Those meetings have involved the White House, the Department of Energy, Naval Reactors, NASA, as well as the Department of Defense.

A NASA-Naval Reactors go/no-go decision on the collaboration is expected shortly, Newhouse said. "We have finally reached the point where there are no more issues involved, with a couple of administrative details remaining," he said.

As example, according to Naval Reactors, they are responsible for more than 100 operating nuclear reactors. Nuclear-powered warships visit some 150 ports around the world – critical to America’s forward-presence strategy and ability to project power.

The mission of Naval Reactors is to provide the Navy with safe, long-lived, militarily-effective nuclear propulsion plants in keeping with the nation's defense requirements, and to ensure their continued safe and reliable operation.

"Naval Reactors has embarked in the oceans of the Earth. Now we want them to embark in the ocean of space," Newhouse said.

NASA and space scientists have begun sketching out a JIMO-deployed Europa lander. But such a probe must be part of the now-projected 3,300 pounds (1,500 kilograms) of JIMO payload, Newhouse said.

There are issues revolving around such a Europa lander, Newhouse added, particularly planetary protection concerns.

First of all, a lander must undergo intensive sterilization. Moreover, there is need to assure that the lander’s energy source doesn’t warm up the moon’s icy environment, even melting through Europa’s frozen face.

"We don’t want to go there later on to find life and not know whether we had brought it in a previous trip," Newhouse said.

The science community involved in looking at the JIMO mission has strongly advocated a lander. A top science priority for a proposed Europa Surface Science Package (EESP) is astrobiology.

That's the view from a NASA Science Definition Team, reporting to the space agency in a February 13 report. The team's study was co-chaired by Ron Greeley of Arizona State University in Tempe, and Torrence Johnson of the Jet Propulsion Laboratory in Pasadena, California.

The NASA Science Definition Team's report to the space agency calls for a JIMO astrobiology goal: "To search for signs of past and present life and to characterize the habitability of the Jovian moons with emphasis on Europa."

"Many high-priority measurements can be made only from the surface of Europa," the report stresses. Once on Europa's ice-covered surface, the package's primary objectives would be "search for organic materials and determination of their composition(s); and "search for chemical patterns in any organics that might be indicative of biological origin," the just-released report suggests.

The same technologies embedded within JIMO are also being eyed for a future mission to one of Saturn’s moons, Titan, as well as Neptune, the Kuiper Belt beyond it, and a voyage to discern the edge of the heliopause -- the boundary that separates Earth's solar system from interstellar space.

"JIMO is the pathfinder…to get through all the nuclear issues," Newhouse said.

Three lead industry contractors are vying for the JIMO work: Lockheed Martin Space and Strategic Missiles, Boeing NASA Systems, and Northrop Grumman Space Technology. In addition, representatives from more than one NASA field center, along with experts in government labs and agencies are overseeing technical issues too.

Although work is underway on JIMO based on a liftoff of 2011 or later, NASA planning charts show an unofficially announced slip to 2015.

At the moment, JIMO tips the scales at about 57,200 pounds (26,000 kilograms) –a whopping 29 tons.

The original flight plan called for JIMO to be rocketed into a nuclear safe orbit high above Earth. It would then spiral out on ion engines to reach Jupiter.

However, those two years of exposure to the space environment – rife with human-made orbital debris, meteoroids, and intense radiation belt hazards – are among issues that have moved NASA to consider putting JIMO on an escape velocity shortly after launch.

But doing so means more oomph from an Earth-to-orbit booster, including a high-energy second stage to send JIMO on its way.

Newhouse said that the sum of those hardware masses equates to about 110,000 pounds (50,000 kilograms). Lifting that much weight off Earth outstrips the capability of top-of-the-line Atlas 5 and Delta 4 Evolved Expendable Launch Vehicles (EELVs), he noted.

Now being studied for JIMO, Newhouse said, is use of a space shuttle derived vehicle – the Shuttle-C. If a heavy-lifter is a no show, then on-orbit assembly of JIMO is possible. In one such scenario, the spacecraft might be joined with a kick-stage motor after it first reaches Earth-orbit.

Nuclear-powered spacecraft gets real

By ROGER SNODGRASS, roger@lamonitor.com, Monitor Assistant Editor

Employing nuclear power systems to explore distant features of our solar system is now off the drawing boards and into testing.

"Nuclear power has long been recognized as an enabling technology for exploring and expanding into space and fission reactors offer essentially limitless power and propulsion capabilities," said David Poston, a 16-year veteran of nuclear technologies in space.

Poston, who leads the space fission power team at Los Alamos National Laboratory addressed a conference in Albuquerque last week on various technical options for meeting the power and propulsion requirements for JIMO, the planned mission to three large jovian moons.

The voyage is still a long way off, but Poston is immediately concerned with the dilemma of balancing the entire flight system against the power it will need.

"The missions vary between 10 and 15 years," he said. "The key thing is power use over the lifetime. Every minute spent fissioning causes more damage to the materials."

LANL is one of the principal partners with NASA's Marshall Space Flight Center, working with counterparts at the space agency's Jet Propulsion Laboratory and Sandia National Laboratories.

Their job over the next few years is to design and build quickly a series of prototype models that can test hardware and system issues, but without using the actual nuclear power upon which the spacecraft will rely.

"We use electrical heaters where the fuel would be," said Poston, who was called in to help conduct a preliminary engineering and design study for JIMO last summer.

Since heat energy is converted to electrical energy by the nuclear fuel in the fission system.

Mission planners tend to scale up their wish list for power demands, eager to take advantage of the scientific and investigative opportunities at hand.

But for every added bell and whistle, for every added demand on data storage and transmission, a proportionately high demand for power will also determine the ultimate configuration of the spacecraft.

"So we must thoroughly understand these technical risks before developing the first system," said Poston.

"For example, there are fewer technical and development challenges for a 500 kilowatt-thermal reactor than a 1,000-kilowatt-thermal reactor."

After circling Jupiter, JIMO will take the local route, spending months at a time, years altogether, circling Callisto, Ganymede, and Europa, in that order. Ganymede is the largest, Callisto, the second largest and Europa is the fourth largest moon in the solar system. The Hubble telescope has found evidence that Ganymede has a thin layer of oxygen.

These intriguing satellites, the size of small planets, appear to contain vast seas of ice.

The presence of water, seemingly enriched by organic compounds, and a planet heated by the tidal and magnetic forces of the giant planet of Jupiter, poses the tantalizing possibility that the icy moons may also harbor living organisms. The plan for JIMO is to orbit them in turn, study them in depth with sophisticated instruments, and scout for life and geological characteristics.

Since each will be subjected to the same kinds of analysis, comparisons and contrasts between them will add to the depth of perspective of the mission.

The idea of using nuclear power in space erupted into controversy in the years leading up to the launch of the Cassini spacecraft in 1997. Cassini used a radioisotope thermoelectric generator, powered by less pounds of plutonium dioxide.

But JIMO will require many kilowatts of electrical power to operate its payload of scientific instruments and as many as a 100 kilowattts of electricity for its ion propulsion drive, according to NASA.

One of its added safety factors is that its fission reactors won't go critical until after a conventional chemically powered launch, meaning that it will be no more radioactive than its fuel until that time.

JIMO's tank will probably contain a relatively small amount of uranium oxide as its nuclear fuel.

When its atoms beginning splitting, it would supply safe, long-lasting, and reliable power

"We have to get a power system on test within the next two years, to prove this thing is going to work," said Poston.

A LANL press release noted that the team has already built successively more powerful components for the nuclear reactor to be used, including a 30-kilowatt reactor core, and a single module suitable for a 500-kilowatt reactor core.

JIMO would be the first of NASA's programs under Project Prometheus, that would use nuclear powered spacecraft to seek answers to how the solar system was created, what its fate will be and whether life exists beyond the earth.

A multi-billion-dollar project, Poston said the engine modules that he is building for testing cost about $500,000 each, and the final power system will cost several million.

http://www.lamonitor.com/articles/2004/02/18/headline_news/news04.txt

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