This is the second in a series of old posts about space exploration in general, and the Bush Moon-and-Mars plan specifically. This is a repost of an old blog post from 2004, so any numbers or links in the post may be out of date. There were also a few comments to the original article, that you may or may not want to read.
In this installment, we have my half-assed explanation of the conceptual problems behind the Space Shuttle program:
There are essentially two arguments for why we ought to support manned space flight, and if you dip into the comments at any of the other fine blogs linked in my last post, you’ll find plenty of people offering different variations of each. One is a sort of Manifest Destiny argument– that we as humans have an inherent drive to explore and expand, and this must inevitably lead us into space. The other is the Paranoid Chicken argument– that we can’t have all our metaphorical eggs in one basket, and putting colonies on some other planet is imperative because it’s only a matter of time before some event (natural or otherwise) brings civilization to an end.
These are fine arguments, as far as they go, but neither of these is an especially convincing argument for funding the program we have right now. There’s not a lot of exploring of the solar system that people can do better than robots, at present, and putting a self-sustaining colony on another planet is decades off, at best. Given all the other things we have to deal with on Earth at the moment, there just isn’t enough spare money to make much immediate progress on either front at the moment. Delaying the rush to space a few years (or even a decade or so) isn’t going to have much long-term impact.
More importantly, the current space program doesn’t actually do much of anything to advance either of these goals. When you talk about manned missions, what we have is not so much a space program as a low-Earth-orbit program. The Shuttle barely gets out of the atmosphere, let alone into interplanetary space. And it’s really not generating any momentum to go beyond that level. Another twenty years of dinking around with the Shuttle and the International Space Station won’t get us any closer to putting colonies on other worlds, or even having the ability to detect and divert those killer asteroids that space advocates are so worried about. We’d probably be better off with no manned space program at all than what we’ve got now.
A large part of the problem is the Shuttle itself. The basic concept is a good one– a reusable launch vehicle capable of lifting a large payload into orbit and returning safely to Earth– but somewhere in the long design process, most of those virtues got lost. The payload isn’t all that large, the turnaround between missions has never been as fast as advertised, and it’s not even re-using most of the bits that supply the lift.
There’s also an element of hubris in the problems with the Shuttle– it was assembled using things that we thought we understood, and clearly, they don’t work as well as expected. It’s an absurdly complicated system, one that requires a huge number of elements to function properly for safe operation, which is the sort of thing that should only be attempted when everything involved is well understood.
The Columbia disaster is a good illustration, as I said last year. The safe return of the Shuttle is entirely dependent upon the heat shields and tiles, which are known to be fragile (tiles have been falling off the damn thing from the very beginning), and potentially subject to damage on launch. And yet, not only was there no way to repair damage to the tiles on the wings after launch, there wasn’t even any way to check whether there’d been any damage done.
That’s just insane. If somebody offered you a car that had a non-zero probability of containing a bomb that would be armed on ignition, and explode violently when you stopped, killing everyone inside, you’d be a fool to take it, let alone pay $4 billion a year for it. And yet, that’s what we’ve got with the Shuttle.
(A case could probably be made that the “we can’t even check it out, let alone fix it” thing was a cultural failure as much as an inherent technical problem with the Shuttle. The fatalistic attitude NASA seemed to take toward the whole thing is a far cry from the “can-do” attitude of popular myth (It’s not something you can imagine Ed Harris saying in Apollo 13, for example). There ought to have been some way to jury-rig things to allow a look at the underside of the Shuttle, and go from there. This is highly dependent on how much truth there is in those myths, though, which is something I’m too young and ill-informed to evaluate.)
I’m old enough to remember when the space program was still exciting, and enough of an SF fan to find the idea of off-planet colonies incredibly cool, but this isn’t helping. If this is the sort of thing we’re buying with the Shuttle program, it’s time to scrap it and start over.
There are lots of Shuttle-alternative proposals out there, ranging from the fairly reasonable (go back to big rockets) to the almost-indistinguishable-from-what-we’ve-got (the “space plane” proposals), to the insanely ambitious (a space elevator). The “space plane” idea is basically the Shuttle as it was meant to be, but I don’t really trust it to avoid the failings the Shuttle has. Space elevators are a lovely idea, but have two major defects: 1) materials technology just isn’t there yet, and 2) anybody who thinks this is a Good Plan in a world containing maniacal terrorists really needs to go read the end of Red Mars again.
(A fourth option would be to basically put manned space flight on hold until technology advances to the point where we can do it more safely and cheaply. Some might claim that that’s actually what we’ve got now– a $4 billion/year holding pattern…)
In the end, I lean strongly toward the first option– we don’t have to go all the way back to the tiny capsules on huge rockets of the Apollo days (though “Spam in a can” was arguably better than what we’ve got now), but simpler is almost certainly better. Go back to putting payloads on big rockets, and work back up to complicated systems, once we’ve got a better handle on what we’re doing. (For example, you could perfectly well use rockets to build a space station that would provide a platform for in-flight maintenance on Shuttle-like craft. Once you’ve got that, then start working on space planes.)
Of course, while we’re at it, we should come up with some sort of program that actually makes progress toward a reasonable goal. That’s the point of President Bush’s new proposal for a base on the Moon, and also more ambitious things like Robert Zubrin’s “Mars Direct” proposal. Space colonies are a perfectly reasonable long-term goal, but if that’s what we’re going to try to do, we ought to be trying to head in that direction, as opposed to noodling around in low Earth orbit.
I should note right up front that, like most people who have commented on this, I doubt that the Bush plan will turn out to be a Good Thing in the end. Not so much because I think it’s inherently a bad idea as because it’s being put forth by the Bush team. To date, I have not been impressed by their sincerity, competence, or good will, so I have grave doubts that this is actually a serious plan that will really improve NASA, as opposed to a publicity stunt, or a disguised plan to funnel yet more money to wealthy Republican donors.
In terms of laying out a reasonable plan for the future of space exploration, I actually think the Bush proposal is remarkable for its lack of grave conceptual idiocy. As this is somewhat at odds with the conventional wisdom among blog commentators, I should probably expand on that, and I will. In another post.