Five years ago, the George W. Bush administration concluded that not only was the Space Shuttle too expensive to operate, it also wasn't safe enough to continue operating. Actually, these are two things that all administrations since Ronald Reagan's should have acknowledged. Perhaps they did, but the alternative of ponying up the money to develop a replacement system was even more unpalatable. So, at least Bush announcing the obvious was a step in the right direction, albeit long overdue.
However, Bush's solution was problematic. It approved the development of a system that not only would replace the Space Shuttle's role in low Earth orbit transportation, but would also encompass elements that would be designed as part of an manned interplanetary system. The last time the US developed a manned space system that was designed to do a whole lot of different things, it wound up with the Space Shuttle. So, in a sense, Bush's decision to replace the Space Shuttle was itself a prisoner of the Space Shuttle paradigm: we must develop a new system that can do whatever we might later decide to do in space. A design for anything is optimized for nothing, but that is what we get in the absence of a strong national space policy commitment to do something specific.
Even worse, Bush's solution for replacing the Space Shuttle created a planned four-year gap, during which American astronauts would be forced to hitchhike on some other national human spaceflight system to the International Space Station. Consider the history of transitioning from one manned system to another. There was no planned gap between Mercury and Gemini, yet there turned out to be nearly a two-year gap. There was no planned gap between Gemini and Apollo, yet again there turned out to be nearly a two-year gap. Disregarding the Apollo Soyuz Test Project, because it was a deliberate "gap filler," the planned gap between Skylab and the Space Shuttle was four and half years; however, that gap ultimately grew to seven and a half years, as the Space Shuttle turned out to be more expensive to develop than anticipated, and Congress appropriated less funding than anticipated. So, it is little surprise that the initially planned four-year gap between the Space Shuttle and the Constellation system is beginning to look more like seven to twelve years as Constellation becomes more expensive and the funding environment becomes more stingy.
Problem: Ares I development costs are mushrooming and it has performance problems, the most reported of which is severe vibration.
Alternative: Upgrade existing, proven launch systems to assume Ares I missions.
Options: Atlas V, Delta IV, and/or Ariane 5, all commercially operated.
Problem: Orion is being designed to unoptimally operate in low Earth orbit, translunar space, and interplanetary space.
Alternative: Design an optimized manned system for low Earth orbit, and another optimized system for beyond.
Options: Manned upgrade of the Dragon and/or Automated Transfer Vehicle cargo systems.
Supported policy goals: Constrained budget, maintenance of American manned access to low Earth orbit, eventual development of American manned access to translunar and interplanetary space, and development of commercial manned LEO services.
Canceling the Ares I launch vehicle would liberate funds that could be applied to upgrading Dragon and/or ATV to an optimized manned low Earth orbit system, and to later upgrading Atlas V, Delta IV and/or Ariane 5 as launch vehicles for Orion, with possible competitive fly-offs in either case. With Dragon and/or ATV as LEO solutions, Orion can be deferred until it is needed to support Altair/Ares V lunar missions, resulting in additional near-term cost savings that can be invested elsewhere. Meanwhile, Orion can be optimized for manned translunar and interplanetary missions.
Additionally, this scenario gets NASA out of the manned LEO transportation business, a role it has filled for 50 years. Vacating this role would finally free NASA to reach beyond LEO, and would create opportunities for commercial ventures to compete for manned LEO services. As a matter of national space policy, I believe it is time for NASA to move on, to focus on sending humans into deep space, and to leave near Earth space to free enterprise. I certainly don't have access to the technical and budgetary information to make the calls regarding cost, schedule and performance issues of this scenario. This is just my back-of-the-envelope look at where we stand and where we can go from here.
13 August 2009
American Manned Spaceflight: Quo Vadis?
Labels:
altair,
ares I,
ares V,
ariane 5,
atlas V,
constellation,
delta IV,
dragon,
orion,
outer space,
space policy,
space shuttle
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