The latest presentations to the Future in Space Operations (FISO) group were given by Mark Holderman and Edward Henderson of NASA JSC. Their slides (available here) are really quite fascinating.
Henderson reported (ppt) on the activities of the Technology Applications Assessment Team (TAAT), which is examining several “key technologies that can advance Space Exploration” and “can be done soon” and “are affordable”.
He listed six technology applications that they are focusing on: satellite servicing, ISRU on the Moon, a SBSP demo, solar electric propulsion vehicle, propellant depots, and the Multi-Mission Space Exploration Vehicle (MMSEV). He described each of these and then Holderman gave a presentation (ppt) specifically on the MMSEV study for which he is the lead.
The Nautilus-X MMSEV is intended as a reusable in-space vehicle for cis-lunar and deep space missions. It would offer a sizable volume to sustain a crew of six and hold enough supplies to sustain a two year mission.
Radiation mitigation strategies, such as creating safe zones with water and H2-slush tanks, are being investigated. It is “capable of utilizing variety of Mission-Specific Propulsion Units [integrated in LEO, semi-autonomously]”.
Most strikingly, it would include a ring centrifuge to provide partial gravity for maintaining crew health.
The MMSEV would be assembled in orbit primarily from expandable structures, e.g. Bigelow modules. They believe construction would require 2-3 launches of a HLV, particularly for the core module, and the rest with commercial vehicles. Orion or commercial capsules would provide transport to/from earth and Descent/Return vehicle(s) would be used for excursions to other destinations. The MMSEV could also dock with the ISS.
Estimated cost and time: “$3.7 B DCT & Implementation 64 months”
The centrifuge includes both “inflatable and deployed structures” and could “utilize Hoberman-Sphere expandable structures”. The rotational hardware would be derived from Hughes 376 spin-stabilized ComSats.
The centrifuge would first be tested on the ISS.
This could be done in a way to “impart Zero disturbance to ISS micro-gravity environment “. The goal is to deliver the system with a single Delta-IV/Atlas-V launch.
Here is a table of partial gravity values versus RPMs and ring diameter:
The estimate of the cost and time: “<39 months $84-143M" Other views of the ISS centrifuge: The basic design of the MMSEV could eventually be expanded for extended duration missions - Yes, I'm sure this will all be quickly dismissed by many as Powerpoint fiction but I still find it quite impressive in several ways: /-- It illustrates how the use of Bigelow style expandable modules provides for great flexibility in design and in the means of delivery. /-- It takes direct advantage of the tremendous experience in assembling structures in space that NASA has gained in the past decade. NASA knows how to do this. /-- It would work very well with fuel depots. /-- The contrast is striking - Constellation would have had small, single-use, expensive systems in operation perhaps by 2030. MMSEV would be a honest-to-goodness space cruiser in operation by 2020. /-- The first pass at the design cost and schedule finds it cheaper than the Orion capsule alone. Yes, I'm very skeptical of costs and schedule estimates for projects done in-house at NASA. The agency's overhead eats up huge amounts of money. But this is still a remarkably low cost estimate considering the incredible capabilities that the MMSEV offers. It would be interesting to see how many launches it would take if the MMSEV was built solely with commercial vehicles and how that would affect the cost. If nothing else, it is encouraging to see NASA focusing at last on innovative concepts that will lead to genuine spacefaring. URL: http://hobbyspace.com/nucleus/?itemid=26786