One area of debate about NASA’s proposed new direction that has gotten less attention than the future of Constellation or commercial crew is development of a heavy-lift launch vehicle. The proposed plan would defer a decision on an HLV until as late as 2015, while working on technologies that could either be utilized by it or otherwise affect such a vehicle. However, in the outline of the authorization bill being contemplated by the Senate Commerce Committee, development of an HLV would be moved up to 2011, in part to serve as “a contingency capability to the ISS” in some manner.
In a brief white paper released Wednesday, Marshall Institute president Jeff Kueter examines this issue. While he calls the administration’s approach “reasonable enough”, he notes the criticism that it “lacks focus” and has uncertainties and potential delays associated with any such effort, as well as the impact of a delay on the industrial base. “The risk with the current approach is that the U.S. will be left without a viable program for deep space exploration in the latter years of this decade and the early 2020s,” he writes. He suggests something of a middle ground: don’t pause the development of an HLV, but also continue the R&D program proposed in the new plan in some form in parallel, acknowledging that “cuts to existing programs, reallocations from new initiatives, or new funds will have to be found to accommodate it.”
The Planetary Society, which has endorsed the administration’s plans for NASA, also addressed the HLV question this week as part of a broader update on the FY11 budget proposal, but doesn’t take a strong stand one way or another. “We at The Planetary Society strongly support a heavy-lift (deep-space) rocket, but should it be funded now, five years before we really need it, given that there are no funds yet available to build the spacecraft that will use heavy-lift?” they ask. “Both sides of this argument have merit.” However, one of the society’s board members, Neil deGrasse Tyson, endorsed an accelerated HLV development in a letter to Congress last month “provided it does not compromise the budget projections the White House has given for the agency.”
Eric Sterner, in a Space News op-ed posted online Wednesday, sees the HLV strategy as part of a broader lack of direction, and potential lack of funding, for the agency’s proposed exploration plans. “It’s like deciding you’re going to begin studying the internal combustion engine so you can make an informed decision about whether or not to purchase a car five years from now with the expectation that you might then use the car to go someplace interesting, without committing enough resources to complete your studies,” he writes.
One issue, though, is often overlooked in the debate about when to start development of an HLV: what, exactly, is a heavy-lift launch vehicle? Is it something similar to the Ares 5, designed to carry as much as 188 metric tons to LEO? Or would something smaller—125 tons? 100 tons? 50 tons?—be sufficient, given that a smaller vehicle would presumably be less expensive to develop and operate? While, as Kueter notes, five years’ worth of technology development might not develop a propulsion breakthrough (getting an American equivalent of an RD-180 engine might be more realistic), technology demonstrations elsewhere could affect the sizing of an HLV. For example, as others have noted, on-orbit propellant depots could eliminate the need for an Ares 5-class vehicle entirely since propellant could be launched by smaller vehicles and transferred to a spacecraft headed beyond Earth orbit, rather than launched together with the spacecraft on a single HLV. Of course, that depends in part in knowing exactly where you’re going beyond LEO, and how.