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Old 10-23-2005, 10:39 PM   #18 (permalink)
billege
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I want to add some new pictures. NASA put up some absurdly huge renderings of what the new ship should look like. They're massive resolution. I mean, massive.

I mean 5610x3156 massive.

Fast image serving though.

I also have to respond to a ton of comments I read on digg, where I originally saw the link to these pics.

I thought about spewing on my blog, but then thought better of it. I want discussion.

The majority opinion of the self appointed rocket-scientist crowd is that the "old style" rockets must be a huge step backwards. One of the most commonly referenced "reasons" the crowd put forth is that the rockets are disposable, therefore both stupid and bad.

Just for the good of my own self and general awareness, I have to respond to the idea that the type of ship depicted is "bad" "dumb" "a step backwards" etc. Seriously. There are some people out there that think they know everything, and I want to help make sure there are less of them. I hope to do this by putting correct info out in the world, or at least correct points for the discussion.

For starters:
The use of disposable rockets is not automatically dumb, overly costly, etc. That’s one fact we have to get straight right off.

The space shuttle has proved that human beings do not yet have the technology level to make a space plane that operates like the shuttle workable. We just can’t build, at a reasonable cost, a plane like that. It’s too complicated, and it’s not working. This is evidenced by the very high costs, low number of flights per year, time between flights, and continued catastrophic failures.

A disposable booster design has several advantages that are not to be casually dismissed. One of my favorite authors (Steven Baxter) puts the reasons well in some of his books. One of his characters builds the “BDB” or “Big Dumb Booster.” Given the level of actual human technology, and not what we wish we had, this idea makes the most sense.

You build exactly like the description says BIG and DUMB. You build it big, because you need to shoot a ton of shit into orbit. We’re not going to the moon or anywhere else useful by sending up ten tons at a time (I have no idea what the shuttle lifts, I’m making a case for “small” where “small = ten tons.”) We will get things done by lifting a thousand tons per shot. Whatever the actual goal, it needs to be massive.
The other side of the equation here is DUMB.

Your successful booster is dumb, and in the process it’s going to be disposable. This is not bad.

It’s dumb, because it really embodies KISS. The BDB shoots as much mass into a desired orbit as possible, that’s its job; it’s a “mass lifter” not an ocean liner, or the starship Enterprise. The BDB benefits from elegance of design by not having to be reusable. Reuse, raises the level of complexity by an order of magnitude.

Example: When designing a seal to last 1 flight, you only have to do the testing to replicate conditions on one flight. You only have to model 1 flight’s worth of stress. The solution can be elegant, cheap, simple, etc. It has to work once. That’s much easier to prove and guarantee than one that must survive multiple uses.
When modeling multiple uses the testing becomes exponentially more difficult, and it’s not just a matter of more computer modeling time. If only it were…. No, you have to remember there is an organization that has to have proved to it that a part can last multiple times. Now it has to be heavier, deal with repeated loads, be certified to deal with the unknown, multiple times. This is difficult. It’s not a trivial matter of telling a computer simulation “run the tests 3 times.” And even if it WERE, that’s not to say the fix is easy. Maybe a simple light-weight part will do you for one flight. Maybe that part fails spectacularly on the 3rd flight. If it’s reusable, you have to replace it every flight to maintain a man-rating factor. Then the processes have to be in place to monitor that part, to validate it was changed, to test the replacement was done right, to validate the parts around it that were moved, disturbed or changed, during the replacement were not harmed.

All that validation is where the shuttle becomes too complex for us. If you have a part that you KNOW will survive 3 flights, and your minimum safety ratings maintain a 1 to 3 relationship, which means every part must be at least 3 times safer than an absolute minimum, you have to replace all those parts every flight. The record keeping is a nightmare in and of itself. The processes to make sure flawed humans did all the work right is ALSO a nightmare in and of itself.

A disposable rocket saves you time and money by chucking all that. You don’t HAVE to make parts that last multiple missions; you just have to make it work once. If a part you put in is good for 3 shots, you have a 3x safety factor, and you’re good to go. Install it and forget it. The part isn’t going to return for its “next” flight, and it’s not going to have to be X-rayed, and tested, and validated to see if it has to be changed or modified for a “next” flight. All that goes with a reusable craft is what makes it hard for us humans to do.

If we HAD nifty tech that let us build incredible materials that held up forever, we’d be set, THEN a reusable rocket makes sense.

For now, you build something cheap, simple, strong, and you shoot the damn thing up at the sky. When you’re up there, you can get clever. Now you can make a craft that goes to Mars, and does all sorts of cool stuff.

As to rockets with the capsule on top being a step backwards, I say “not hardly.”

The shuttle showed over and over, especially recently how damn dumb it is to put your crew vehicle under a stack of explosives, where shit falls on it. It’s common sense.

Problems usually dictate simple solutions. The Apollo guys hit on it in the 60’s and it’s as good now as it was then. You put your crew above everything. If the rocket blows up, you light the escape rocket and pull the whole damn crew module away from the explosion. Obviously, that doesn’t work with the shuttle.

The shuttle was obviously a bad idea when it was conceived, and it’s a bad idea now. We don’t have Star Trek tech, and we won’t for a long time.

If we want our species to survive, we need to get into space, and we need to be there in a big, permanent way. We’re not going to get there dicking around in LEO. We’ll get there by throwing as many people and supplies into space as we can. We’ll shoot them up as fast and cheaply as we can.

The first ones up win; it’s pretty obvious. I’m not able to see the future, but the first country that makes it into space and starts exploiting the resources up there wins. This is a long term game humanity is playing, and we don’t win by dicking around with extremely complicated gliders that keep blowing up. The Chinese will take our lead in space away. They’re a lot hungrier than we are, and I think, they are willing to blow people up (in failed flights) for the good of the other 5 billion of them. We Americans, are not. Honestly, it’s going to happen. People will die, and they will die trying to get into space. Keep it to a minium, because blowing up experts in anything is an econmically expensive proposion, but damnit, keep on going.

Whoever wants it worst wins. Whoever opens up the consumables loop, by exploiting space’s resources, has a huge lead in surviving.

We need to get there now, and the best way to do that is with cheap rockets, that work. When they get up there, and we KEEP people up there, we provide dreams. We make the space race something worth trying for. We open up the new world again. That’s a dream worth dying for, and I hope it’s one we take our shot at.
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