The administration of Prometheus is being split between Space Science and Exploration Systems. Code S will retain control over the JIMO science guidelines and the new power units, and the new Code T will take up responsibility for development of the spacecraft and the propulsion system.
JIMO has the potential to be the biggest and most expensive spacecraft NASA has ever built.
Hmm…methinks they mean “robotic probe” rather than “spacecraft”. Even with nuclear power and a new (scaled up) propulsion system, it’s hard to imagine the thing costing as much as Shuttle. Let alone ISS.
Mills said the spacecraft could easily be 50 meters long when fully deployed — about half the size of the international space station.
It’s going to be a bit tricky to pack that on an Atlas V Heavy (or a Delta IV Heavy), even if it does fold down into a tidy little bundle for launch.
Space.com has an article on this subject at
http://www.space.com/businesstechnology/technology/jimo_fin_040219.html
Concerning JIMO:
“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.”
Now a question, or two.
A fifty meter craft could be attached in one piece to the side of the orbiter stack. No origami necessary. How much might the JIMO project save in engineering and fabrication costs if they could avoid all folding and on orbit assembly? Are the stresses of launch greater, less or the same for an unfolded JIMO versus a version that is folded up and opens after arriving on orbit?
I don’t know about a fifty-meter craft, since the ET itself is only 154 feet long. You’d need a whole lot of aerodynamics work to make a go of that sort of configuration, plus the resulting mods to the tank, the interfaces, the TPS, etc. It could be done, don’t get me wrong, but it would be such an investment that it would probably make it worthwhile to just convert the ET to an inline-payload/offset-propulsion configuration and make a multi-purpose HLLV out of it. The primary attraction of a side-mounted payload with ET-derived is that, if kept to roughly the Orbiter envelope, the launcher’s overall development and facilitization costs can be kept down — hence Shuttle C resembling the Orbiter fuselage.