11 June 2003
NASA nuclear orbiter to search for oceans on 3 Jupiter moons
Lockheed gets $6M to design spacecraft
By Jim Erickson,
Rocky Mountain News


Denver's Lockheed Martin has been awarded $6 million from NASA to help design a nuclear-powered spacecraft to search for oceans beneath the icy surface of three Jupiter moons.

Previous missions have uncovered tantalizing hints that the three planet-sized moons - Europa, Callisto and Ganymede - may harbor vast oceans. Scientists are intrigued because all known forms of life require liquid water.

The proposed Jupiter Icy Moons Orbiter would use radar to measure the thickness of the ice shells and search for oceans beneath them.

"These moons are unique in the solar system because they're icy, but they also may be wet. There may be liquid water there as well," said Ben Clark, a planetary scientist at Lockheed Martin Space Systems.

"You sort of get a triple bang for the buck, because you go to this one planet and there are three plums waiting to be picked," Clark said Tuesday.

Lockheed Martin, Boeing and Northrop Grumman each received $6 million to complete eight-month design studies for the mission. When the studies are completed, a contract is expected to be awarded to one of the aerospace companies.

Launch would not occur before 2011.

The Jupiter Icy Moons Orbiter, known as JIMO, would be the first interplanetary space probe powered by a nuclear fission reactor.

The Soviet Union put more than 30 reactors into space aboard spy satellites in the 1970s and '80s, said John Casani, NASA's project manager for the Jupiter Icy Moons Orbiter. The United States launched an experimental reactor in 1962, but it failed within a few hours, he said.

JIMO would convert heat from the reactor into electricity that propels the spacecraft. The use of electric propulsion was successfully demonstrated several years ago on NASA's Deep Space 1 mission.

JIMO would have 100 times more power than a conventionally powered spacecraft of comparable weight. That would enable it to use high-powered science instruments, and it would boost the data-transmission rate back to Earth.

NASA's recently completed Galileo mission to Jupiter found evidence of water beneath the surface of Europa, Callisto and Ganymede.

"I think the evidence from Galileo is pretty conclusive that there is water there, certainly below the surface of Europa and probably for Ganymede and Callisto as well," Casani said. "The confirmation of that will be possible with the instrumentation on the (JIMO) spacecraft."

JIMO would cost several billion dollars. It is part of a new NASA program called Project Prometheus, which will attempt to demonstrate that reactor-powered spacecraft can be operated safely and reliably.

NASA expects to spend about $3 billion over the next five years on Project Prometheus, Casani said.


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