Space agency outlines three spirals for crew exploration vehicle, with 2014 flight goal
NASA's request for Crew Exploration Vehicle (CEV) proposals, issued last week, asks bidders to offer a system that will become more affordable as it evolves. A key goal of the agency's plan to develop exploration capabilities in spirals is enabling the insertion of technologies that improve performance and reduce cost over time.
The request for proposals (RFP) outlines three spirals – Earth orbit capability by 2014, extended lunar exploration in 2015-20 and long-duration lunar exploration after 2020 – and asks bidders to offer a CEV that meets Spiral 2 at a minimum, with Spiral 3 as a goal. Competitors have been told to aim for a first manned flight in 2014 and up to four missions a year over a 20-year life.
The Spiral 1 CEV will establish the capability to check out crew transport system elements in low-Earth orbit, and will act as an in-space testbed for new exploration systems developed under future spirals. The second iteration will establish the capability to conduct manned missions on the Moon's surface for a minimum of four days, extending up to "several months" under Spiral 3 as NASA tests technologies and operational techniques for future short-stay Mars missions.
The CEV is intended to carry four crew for a maximum of 16 days. Requirements include a gross lift-off weight of less than 20t, an abort capability during all phases of flight and two-fault tolerant safety-critical systems. Trade studies by the contractors will look at launch weight, abort ability, mission duration, crew sizes up to six, and CEV support for crew transfer to and from the International Space Station.
CEV proposals are to be submitted by 2 May, with the selection of two contractors scheduled for September. Both teams will conduct risk-reduction demonstrations under the Flight Application of Spacecraft Technologies (FAST) effort, leading to selection of a single contractor at the end of 2008 to develop the CEV. The RFP limits the FAST flight-test effort to 35% of the contract value.
Teams are permitted to include foreign subcontractors, but NASA will examine each "for a justifiable business case defending this decision", the RFP says. Competitors are also allowed to propose the inclusion of NASA field centres as team members.
The RFP outlines NASA's "point of departure" architecture for its Constellation system of systems, of which the CEV is the first element. Spiral 1 components include the CEV and its launch vehicle. Spiral 2 adds the Earth Departure Stage for transport to the Moon; the Lunar Surface Access Module, which provides crew habitation and transport at the Moon; and the uncrewed Cargo Delivery System and launch vehicle. Not completely defined, Spiral 3 adds surface elements to support long-duration missions.
GRAHAM WARWICK WASHINGTON DC
Source: Flight International
