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Originally posted by: Jefferson Morris
"NASA's Jet Propulsion Laboratory is evaluating industry proposals for the preliminary design of the Jupiter Icy Moons Orbiter (JIMO) spacecraft, in anticipation of awarding a contract by October.

Teams led by Lockheed Martin, Boeing and Northrop Grumman submitted their final proposals last month, according to Ray Taylor, acting director for Project Prometheus at NASA's Office of Exploration Systems. In collaboration with JPL, the winning team will create a preliminary design for the spacecraft, which NASA plans to launch sometime in the next decade.

JIMO will be the first flight demonstration of the space nuclear power and propulsion technology being developed under Project Prometheus. Such technology is essential to in-depth study of the outer planets, according to NASA, where solar power is of little use.

Using ion-electric thrusters powered by the heat from an onboard nuclear fission reactor, JIMO would orbit Jupiter's three icy moons - Callisto, Ganymede and Europa - in succession, investigating their composition, history and potential for sustaining life. NASA's earlier Galileo mission found evidence that these moons may feature subsurface oceans, making them prime targets for science.

"Galileo did a terrific job, but was only able to fly by the moons very periodically," Taylor said in a presentation to a National Academies panel in Washington Aug. 9. "Cassini will no doubt do a fine job, but there too, is only able to fly by Titan. To do the long-term, detailed reconnaissance of objects such as Europa and Titan really requires ... getting into orbit around those objects."

After launch no earlier than 2011, JIMO would cruise to the Jovian system under steady but slow acceleration from its electric thrusters. The spacecraft then would orbit Callisto for at least 60 days, then move on to orbit Ganymede for at least 120 days, and finally Europa for at least 30 days. NASA also is considering the possibility of a Europa lander that would be deployed by JIMO. At the end of its mission, the spacecraft would enter a "quarantine orbit," never returning to Earth.

The House Appropriations Committee last month voted to cut NASA's fiscal year 2005 budget request for Project Prometheus by $230 million, which primarily would come out of the JIMO effort. The House has not yet conferred with Senate appropriators on a final NASA budget.

Prometheus partners

Project Prometheus began its existence as the Nuclear Systems Initiative (NSI) in 2002 (DAILY, Oct. 24, 2002). Administrator Sean O'Keefe later renamed the effort and in late 2002 asked NASA scientists to devise a flagship mission to focus the effort and "drive the technology to fruition," according to Taylor. After considering missions to Mars, the asteroid belt, or various comets, the agency settled on JIMO.

NASA's partner on Project Prometheus is the Department of Energy's National Nuclear Security Administration - Naval Reactors (NR) group, with which it recently signed a Memorandum of Understanding (MOU). The JIMO reactor would provide more than 100 times more usable onboard power than has been available to previous science probes, according to NASA, while demonstrating that civilian nuclear reactors can be operated safely and reliably in space.

NASA already has chosen Northrop Grumman and Princeton University to lead teams conducting advanced electric propulsion technologies research to support Project Prometheus. Northrop Grumman was awarded $3 million to develop a nuclear-electric pulsed inductive thruster system, while Princeton was awarded $4 million to advance the technologies of a lithium-fed magnetoplasmadynamic thruster system.

Future applications for the power and propulsion technologies being developed for JIMO include detailed study of Saturn and its moon Titan, rendezvous with multiple objects in the Kuiper belt, returning a cryogenically preserved sample from a comet, or an "interstellar precursor" mission that would travel 200 astronomical units (.003 light years) in less than 15 years, according to NASA.
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I have heard some scuttlebutt that JIMO is approaching 100 tons now. The idea is that the safest way to launch this is on an insertion stage so that they can pull the rods on this thing when it is on its way. First it was 50 tons--but I am hearing 100. Since this will not help human exploration there is now a bit more talk about nuclear thermal. I am very glad--since I despise nuclear electric. Nuclear-Thermal is actually more near term tech, as you NERVA fans know by know. The use of an oxygen afterburner will give both high ISP and thrust. NEP should come later, as a precursor interstellar probe with NTR boosting something like JIMO much later on, where the nuclear-electric can build up high speed over time.

I can't tell you how the nuclear thermal fans in NASA have been crapped on--but I think there will be some changes now.

But first--what we need is heavy lift. http://www.spacedaily.com/news/oped-o4zc.html

www.k26.com/buran

Don't think you are going to do this with EELVs Hydrogen boil-off puts the nix on the 20 tons at a time assembly that delays ISS completion.

One day--I hope we can have Sea Dragon. The hull of which can be used for the sustained thrust of a nuclear salt-water rocket--which will be a little easier to take than the putt-putt Orion.