I’ve been ambivalent about the space shuttle program for decades — not because I’m anti-space, but because I think the shuttle was government methadone to replace a real space program. At that, I hadn’t connected all the dots the way Scott Locklin has here:
The Space Shuttle, an object lesson in the Sunk Cost Fallacy, has been with us since my early youth. This preposterous boondoggle was originally supposed to make manned space flight cheaper: to the point where getting a pound of matter into space would be as cheap as sending it to Australia. That was the only purpose for building the damn thing in the first place. The idea was, if your spaceship was reusable, it would be cheaper to send people and heavy things into space. If using the same thing multiple times isn’t cheaper, well, what’s the point? Conspicuous consumption, perhaps?
In one of its original incarnations, the Shuttle was supposed to launch like an ordinary aircraft. A jet + rocket powered “first stage” heavy lifter would propel the craft into the upper atmosphere, and the rocket propelled second stage would send the thing into space. Seems like a good idea to me. Jets are pretty easy to fly and maintain cheaply. Jets also don’t have to carry vast quantities of oxidizer. Plus; you get to reuse the whole mess.
Unfortunately, the politicians decided that building the first stage heavy lifter would cost “too much.” Instead they changed the design, and strapped a couple of solid rockets to a beefed up “orbiter” and giant non-reusable fuel tank. That wasn’t the worst of it: those pieces should have still in principle provided for a cheap launch vehicle. In practice, the silica tiles and engines turned out to have very high maintenance costs involving substantial labor, and turn around times were 1/6 of what they should have been, making the thing 6 (though more like 10) times as expensive as it was designed to be.
The goal of the space shuttle program was to have safe, re-usable spacecraft that could lift heavy loads to low earth orbit at a cost of about $50 per pound. What they ended up with was a dangerous fleet of hangar queens that took loads to orbit at an estimated cost of $50,000 per pound. That’s quite a missed set of goals.
Locklin is right that the shuttle was an enormous waste of money, but he’s fudged the history of the program badly. He’s a physicist, not an historian, and—well, nobody’s perfect.
One of the shuttle’s earliest incarnations was not the delta-winged thing launched by an enormous “mothership” that Locklin illustrates in his post. That design only emerged after NASA had gotten into bed with USAF, and the Air Force had bloated the STS design spec to ludicrous heights.
Max Faget’s shuttle design was a small craft with straight stubby wings, useful for hauling people and very small cargoes into orbit. It was designed for fast turnaround inside of a week, and was supposed to be built out of titanium and steel alloys. It would be launched on top of the traditional “capsule”-arrangement booster stack, and was designed to re-enter straight down like a capsule, not the transsonic shuttle profile. It had an air-breathing jet engine aboard, to provide manoeuvrability during the landing phase, and self-ferrying ability to other fields/launch sites.
Soon NASA gets bad budget news, and along comes the Air Force saying, hey, we’ll go to bat in Congress for this thing, but you have to make some changes to accommodate our needs. Immediately the gross weight is inflated so that it can put multi-ton defence payloads on orbit; USAF also wants the ability to do polar orbits and huge crossrange during landing, so that it can end up at any number of air bases worldwide. NASA says okay and convinces itself that with this monster shuttle it can ditch a separate heavy lift booster, using the shuttle to put up its planned heavy space telescopes and space station components.
So the tiny steel-and-titanium jet-powered shuttle gets axed, and primary contractor Rockwell starts coming up with new plans (which is where you start seeing the familiar delta-winged behemoth that Locklin has shown). But building the “mothership” proves too expensive, so that part of the plan gets cut. In order to do polar orbits from Vandenberg AFB, you need more oomph, so the mega-shuttle gets mega-engines, and a mega-tank to fuel them. The weight of the shuttle + payload + tank is too much for the main engine cluster so boosters have to get added.
Rockwell says there’s not enough titanium in the free world to build a fleet of mega-shuttles, and tooling for same is super-expensive. But they know how to work with aluminium, and aluminium is cheap. It also, unfortunately, turns to slag at re-entry heat so now you’ve got to cover the whole mess with heat-ablative tiles and put carbon-carbon leading edges on the nose and wings. And all those tiles add weight, too, so the onboard air-breathing engine is cut and the shuttle becomes a big, heavy glider.
Challenger blew up 5-6 months away from the shuttle’s first Vandenberg launch, but after the accident, USAF pulled its future payload launches from the STS and went back to unmanned Delta LVs. (The expensive, completed Vandenburg site was never used for an STS launch, nor did the orbiter ever get put into a polar orbit.) Now NASA has an expensive shuttle but no USAF pulling in money from Congress. Bush the Elder subsequently scraps commercial-payload shuttle launches, so now the shuttle can’t do anything except put up NASA payloads. Which there are few of.
The only thing that kept it going was flights to Mir, because the Russians designed their station to be able to dock with the Buran shuttle—which was itself designed to use the 1975 APAS Apollo-Soyuz docking device. The US shuttle’s internal design could accept APAS, so Atlantis was modified to include it—and now the shuttle had a destination, and the Russians a customer.
Eventually, Mir got too old and creaky, so NASA convinced Congress to fund the launch of Russia’s first Mir-2 module, which we know as the Zvedza module of the International Space Station.
So the short version is all of the design compromises that made the shuttle expensive and dangerous are directly related to USAF’s spec changes after it decided to contribute to the project. Faget’s version was small, affordable and technically sound. The concept Locklin is showing would still have been expensive and dangerous to operate, as it was still huge, made of aluminium, covered with bricks, and given no easy way to separate quickly from a mothership that had experienced a catastrophic fault.
Comment by Chris Taylor — July 24, 2011 @ 20:31
Wow, I suspect that’s the longest comment anyone has ever posted to the blog. But I think you merely topped your own record, so “Winner and still champion!” 😉
Could Max Faget’s original design be resurrected? It certainly sounds like a useful, cheap alternative to yet another mega-scheme.
Comment by Nicholas — July 25, 2011 @ 09:45
I usually mutter about ‘stupid Air Force making stupid NASA bolt on wings’ and let it go at that. Lugging tons and tons of useless weight to orbit gets me so irked.
I have no idea if the original and sane design could make a comeback. I suspect it can be done, technically. But politics will rear it’s head, the executive branch has no time for this foolish talk of the High Frontier, and spinoffs, and so forth.
In the end, space just doesn’t matter to Americans.
Comment by Brian Dunbar — July 25, 2011 @ 12:36
I have probably oversold the Faget DC-3 concept a little; it was not without its technical challenges too. I recall reading about it with a conventional booster stack, but every drawing I can find shows a fully reusable system with an enormous (though vertically launched) booster plane. I may have mis-remembered that aspect. The booster plane would certainly be enough of a technical and financial hurdle, though it was the AF’s insistence on crossrange from polar orbit that killed the DC-3 idea.
Much of the concept art floating around out there appears to be North American/Rockwell’s larger variant capable of hauling 22,680kg payloads (which is around the capacity of today’s shuttle), rather than the tiny original spec of 5,580kg.
Ultimately if space is going to be commercially viable, a significant lowering of the cost has to occur. One would think a reusable vehicle would help do this, but it all depends on the concept and the technology that underwrites it.
Comment by Chris Taylor — July 25, 2011 @ 14:00