After some Googling, I found that the Crew Exploration Vehicle is to be the successor to the Shuttle.
My first reaction is to hang my head in shame that this is what NASA’s come to. I remember watching the first shuttle flights back when I was in High School, optimistic that the future of space flight would be…something better than the CEV.
So is the CEV a done deal? Are there viable alternatives at this late date? And lastly, is my disappointment misplaced?
Better question: Was the Space Shuttle ever viable? It makes a lot of sense to separate the heavy cargo lifting from the human-lifting, so you only need to worry about extreme safety measures for a smaller vehicle (a 1 in 50 failure rate is perfectly acceptable for an unmanned cargo vehicle; not so much for manned flight). And the CEV won’t actually need to have much more replaced than did the Shuttle: The idea behind the Shuttle was to make it reuseable, but the SRBs and external tank are still discarded every flight, and even the orbiter (the nominally reuseable part) needs extensive maintenance every time.
Actually, the SRBs are reused.
The shuttle came out of the idea that they wanted a “space plane”, the idea being that we would send people up into space and bring them back just as easily as if they were boarding a regular passenger jet. The problem was that the technology really wasn’t there yet. Rather than admit that the technology really wasn’t up to the task, they kept going with the idea, and the space shuttle is the result. It’s hugely expensive, has to be practically rebuilt in between launches, and is downright dangerous to operate. The cost of sending the shuttle up each time is greater than the cost of sending a non-reusable craft up to the do the same thing, which makes the whole re-usability part of it seem rather stupid.
Although I haven’t taken a very close look at the CEV approach, my first reaction is gee, looks like the folks at NASA are finally using their brains. While the capsule idea certainly looks like a leap backwards in technology, the fact of the matter is that they have capsules figured out pretty well. They are simpler, and simpler is by nature safer. If there’s less to it, there’s less things in it that can go wrong.
It looked for a while like the replacement for the shuttle was going to be another shuttle-like vehicle. I think as they played around with the technology and prototypes that they realized the technology still isn’t quite there yet for a “space plane” idea to be practical.
Personally, I prefer safer and cheaper, even if it isn’t quite as sexy.
I wonder if NASA was ignoring some basic rocketry physics in the design of the Shuttle.
After all, it is basically a one-stage rocket - all* of your fuel tank, main motors, main fuel pumps, etc are along for the entire ascent… as opposed to the classic multi-stage rocket where the big pieces are discarded after their fuel is spent.
The Apollo design was a classic - almost nothing returned to earth. That design was originally spit on as crackpot - years of lobbying by the visionary designer proved that it was viable, in fact it was the only possible way of doing a lunar landing and return.
Also, they insist upon a full crew of seven. The life support for the crew and the huge weight of the re-useable components mean that payload is very small, right?
*I realize the SRB’s are jettisoned after a few minutes, and the main fuel tank goes eventually too, but it’s still basically a one-stager.
Mark Wade at www.astronautix.com does have the editorial position that even given the “modular capsule” concept, CEV as decided upon is a triumph of political compromise over engineering and NASA forewent better private-industry designs, to a great extent due to budgetary and political-timetable pressure to get something flying fast, and if possible using the same workforces that are already involved in the Shuttle program, plus a bit of “not invented here” syndrome. I think he’s a bit pessimistic, though the decision on the configuration does lose some flexibility (Wade, and myself, would have preferred something more along the Soyuz philosophy of 3 modules: systems/propulsion; command/reentry; operations/docking – with the latter being suitable for “stretching” in order to do different mission profiles.)
Of course, part of the problem here is that Manned Space Flight is not a profitmaker, so while Lockheed-Martin, Boeing, etc. may have excellent ideas as to how to build a spacecraft right, they have no excuse whatsoever to sink real money into building one unless they already have in their hand the contract from NASA. So they instead have to compete on the basis of who will meet NASA proposal specs, whatever they are, which may or may not be what’s better. But then reality collides with NASA proposal specs and everything has to be revised and, if you’re lucky, someone at some point says, “enough! build what we have worked out so far!” and you end up with a compromise system – or more often, your project just gets cancelled after pouring heavy millions in just design and testing(Remember Space Station Freedom?). And of course, you then have to oversell capabilities and lowball price in order to get the Appropriations Committee to even consider giving you a budget (see: Space Shuttle)
– Aside:
K364, actually, the STS looks to me more like a 1.5-stage vehicle (there are the boosters and SMEs, but also orbital insertion engines that are internally fueled).
The last Shuttle, Endeavour, is payload rated to 24 metric tonnes into LEO, more than an Atlas-V, way less than an Ariane-V. An STS can fly operationally with a crew as small as 3 (pilot, copilot, mission specialist to handle the experiment/satellite launch) or as large as 8.
The real mistake with the shuttle was the attempt at having it be the one do-everything MSF system AND heavy launch system (partly to get the military aboard the program) in the same package, and selling it as the solution to all government spaceflight needs. Imagine instead this stack: a heavy-boost stage of fuel tank +SMEs (make the engine pod recoverable); and an *upper stage * – out of the way of falling ice and foam – divided into two modules: a varying size cargo module for heavy object lifting, and in front the spaceplane with crew compartment and a *smaller * cargo bay for lighter loads, returnable experiment modules, and the manipulator arm. The smaller crew vehicle may have been easier to make more sturdy (or make more of).
–/Aside
The sad part is, there could have been development of a good enough shuttle successor all alongexcept for the inconvenient detail that it would have meant announcing the eventual retirement of the existing shuttles and NASA knew (a) it would look like an admission they had overreached with the STS and (b)they would still not be able to “sell” to the Appropriations Committee going with something just “good enough”.
For some reason, NASA’s institutional culture was that there could be only one major manned spaceflight system going at the same time, that nothing flying under NASA aegis may compete or cast shadows upon anything else programmed under NASA, and that any major change in MSF systems must involve a leap of several orders of magnitude (many worthy incremental-Gemini-derivative proposals were nixed in the 60s because that would be competing w. Apollo and you Did Not Do That).
Oh, yes, technical note:
Of course not all of it is 100% deliverable, as it includes the rails, pods, containers, pallets and other hardware that holds the satellites, cargo, etc. in its place, that stays bolted to the spacecraft; it can cut down as much as 10 tons depending on what it is that you’re hauling.