March 13, 2008

We'll give them two points.

NASA has a prototype of the Orion capsule:

The aluminum and steel cone-shaped object with a pair of white fuzzy dice hanging from an interior beam is the same size and shape of a spacecraft being designed to take astronauts to the international space station and then to the moon.

That's worth two points, I think.

I was reading about the Orion a few days ago. I hadn't been keeping up, so I didn't know that they're scheduled to stop flying the Shuttle in 2010. (And none too soon, either.) I also didn't know what they had planned to replace it.

I'm surprised, and extremely pleased. While the Shuttle has served us well, the "space plane" concept didn't work out the way it was expected to. The original idea was that when nearly all of the equipment was reusable, it would reduce the cost of a launch drastically and have a short turn-around time.

The reality was that when all the equipment was reusable, and very oddly shaped, it meant that the orbiter had to have months of maintenance done after each flight, and the number of potentially-fatal failure modes was immense. Originally they expected to have a shuttle launch about every 10 days, if not even more often than that, but it didn't turn out that way.

The Shuttle fleet is very old now, and there needs to be a replacement. There was a proposal for a new orbital space plane, but that's not what they're going to do. While we were flying the Shuttle, the Russians were continuing to use more classic space capsules, and the fact is that is a better approach. So that's what we're going back to -- only with a difference.

The Russians are using liquid-fuel boosters, which though single use are still expensive and relatively unreliable. The Orion is going to use a solid rocket booster. It's the same fundamental technology used for the Shuttle SRBs now, except there will be only one and it's going to be even larger. And that is a superb idea. Our experience now with the SRBs is that they really are a lot cheaper than liquid fuel, and a lot more reliable. It's definitely the way to go.

Another change: the Orion system will have reusable capsules, but they're not going to try to get 40 years of use out of them. The expected life is about 10 trips. Which means that the manufacturing line will stay open during the life of the program, another plus.

The simple geometric shape of the capsule means the reentry will be easier and safer. No more weird tiles; the heat shield will be a single piece.

And because the capsule is at the top of the rocket, and there's no huge tank of frigid liquified gas, no more ice chunks falling onto the capsule during launch to cause fatal damage. No more Columbias.

This system is cleaner in engineering terms. While it's true that more of the system is disposable, to be used a small number of times or only once, it's also simpler and more reliable -- and that means it will probably be cheaper, and they really will be able to launch more often.

One final nice thing: they're no longer trying to design manned space-truck. When the Orion boosts, all it sends up is people. If they want to send up cargo, that goes on a modified version of the booster, and it goes without a crew.

The Orion system seems like a throwback, since it's based on the Apollo system. But time has passed, and a lot of fundamental technology is changed. Orion is best described as "Apollo done right". And I'm really glad to see that NASA is going to start relying on solid fuel. That's definitely the way to go.

When it comes to rocket science, specialization is the way to go. The problem with the Shuttle was that it was designed to be a jack of all trades. That meant it was master of none, and it meant that it was too complicated and thus too prone to failure. Plus the extraordinary expense per orbiter meant that even this country, as rich as it is, could only afford a few.

With Orion we're moving more towards economy of scale. This truly is "cheaper, faster, better".

And the best part of it: you only send people into orbit when you really need people. Sending people to escort cargo into orbit was always stupid.

I remain profoundly skeptical about the wisdom and feasibility of sending humans to Mars, but if those kinds of plans are what it takes to get NASA to make this move, then I'm all for the dream. Just as long as they give up later.

Use humans in space when only humans will do. Use machines whenever possible: it's safer and cheaper and more effective. By separating cargo shipment from manned flights, the Orion system advances that philosophy, and that's all to the good.

Also, use liquid fuel when only that will do (e.g. on the Orion service module). Use solid fuel whenever possible. That, too, is safer and cheaper and more effective.

Posted by: Steven Den Beste in Weird World at 12:02 PM | Comments (18) | Add Comment
Post contains 867 words, total size 5 kb.

1 Solid fuel is manifestly less safe than liquid, if you remember how Challenger blew up. And it's most certainly not cheaper, because casting costs. There are other downsides as well, for example solids' failure modes develop much faster than liquids and so the early failure detection system and the escape system have to work harder for a solid booster. I'm not even going to bring up the toxicity of solid exhaust, it's for enviros to debate. // Quite aside from the solid debate, Ares-I is a joke. The DIRECT project has proven that a much cheaper system could be built using the same principles, and be truly Shuttle-derived (e.g. not cutting new holes in the launch platform). Ares-I is not Shuttle-derived at all, it's fraud. They have to develop new upper stage engine and essentially new SRB, not to mention the rest of the upper stage. They have to create principially new launch infrastructure. // P.S. Pixy, where are my paragraph breaks?

Posted by: Pete Zaitcev at March 13, 2008 12:51 PM (qNSKg)


Pete, you probably need to dump your browser cache and reload. Likely one of the Javascript helper files didn't download.

The Challenger failure was caused by a management failure. The investigative record on that is clear (and thank you, Feynman, for preventing NASA's management from covering it up!). There was a temperature range in which the SRBs could be safely used, and that launch was in conditions outside that window. Management was under political pressure to launch anyway, and did. It wasn't an indication of inherent lack of safety of solid fuel, which in operational use has been extremely reliable.

The issue with solid fuel is quality control. With poor quality control, solid fuel is very dangerous. But we've been making solid rockets now for decades, and the quality problem has been solved.

Moreover, while it's true that casting solid fuel is expensive, liquid fuel rocket engines are very expensive, and because of the sheer complexity of them are inherently more prone to failure. As a result, to keep them safe, they have to have extreme (and expensive, and slow) maintenance done. In practice solid fuel ends up being cheaper. The only important moving parts on a solid booster is vector control -- which is difficult, but liquid boosters have that, too.

You have to look at the total cost, the total process. It's true that casting solid fuel is more difficult and expensive than filling a tank. But what you spend there, you more than make back on other things that you don't have to do if you're using solid fuel.

There's a damned good reason why all our ICBMs and SLBMs use solid fuel, and have for decades.

Posted by: Steven Den Beste at March 13, 2008 01:05 PM (+rSRq)

3 Unfortunately, it's pretty messed up.  They have serious weight issues, a potentially terminal vibration issue, and a rocket that was supposed to be "completely derived from" existing parts has turned out to be something completely new built from scratch.  Meanwhile, costs and delays have been spiraling upwards.  There's a number of blogs that have been covering this, but I'll refrain from throwing links around without your say-so.

I am now very pessimistic about NASA and their ability to do anything effectively except soak up money.  I'm desperately crossing my fingers for Falcon 9 or Atlas to prove that it can be done for a lot cheaper (admittedly, Atlas isn't very cheap at all unless you buy a lot of them; but, it's still much cheaper than the Stick).  I'm also crossing my fingers for Bigelow... if he successfully builds and sells space on his station, he'll shake things up dramatically just by providing a market.

Posted by: BigD at March 13, 2008 05:10 PM (JJ4vV)


Some parts of NASA continue to do good stuff -- mainly, the unmanned probe groups. It's the manned flight part of NASA, which has the largest share of the budget, which has gotten incompetent and stupid.

Pity, really.

Posted by: Steven Den Beste at March 13, 2008 05:15 PM (+rSRq)

5 Say what?!? Oh, not that Orion. (And you thought solid rocket exaust was bad...)

Posted by: Cybrludite at March 13, 2008 11:17 PM (GDpMq)

6 Cybrludite, don't think of it as a nuclear-bomb-powered space ship, think of it as the world's most powerful pulsejet engine.

...and invest in lead.  Lots and lots of lead.

Posted by: Wonderduck at March 13, 2008 11:19 PM (AW3EJ)

7 Take off and nu...  Oh.  Okay.  Time for lunch?

Posted by: Pixy Misa at March 14, 2008 01:58 AM (PiXy!)

8 Hey, we would have totally been to Mars by now if not for such silly, utterly non-technically objections to Project Orion. 

( its not like you'd use the things in-atmosphere. . . )

Posted by: metaphysician at March 14, 2008 05:26 AM (9Lztf)


ICBM's tended to use solid fuel so they could be be ready to fire on short notice. The more powerful liquid fuels are cryogenic so not storable (this was what killed Blue Streak, Britain's own ICBM. They didn't realise until too late that by the time they'd filled the tanks the launch site would be radioactive dust).

Personally I'd rather not be sitting on a giant firework, especially as they can't be switched off if anything goes wrong.

From what I've read I don't seen any fundamental reason why rocket engines can't be as reliable as jets (IIRC, rocket technology is comparable to 50's jets in terms of design maturity). Reusability and high flight rate is what makes London to Sydney affordable, which uses the same amount of energy as getting to orbit, IIRC. part of the problem with the shuttles low flight rate is due to the design constrictions, and the fact it was designed to keep the Saturn workforce busy.

I've been following NASA's attempts to replace the shuttles since X-33 in the late 90's. So far all that's been produced are lots of pretty pictures and a dollar bonfire.

 Hopefully we are on at the start of the commercial space age, and we'll find out by trial and error what works best, and what most cost effective. I'm still optimistic I'll be able to retire to the Moon or Belt (Mars doesn't really appear to me)


Posted by: Andy Janes at March 14, 2008 06:22 AM (1xA29)


The problem with private enterprise going into space is that, IIRC, there is, aside from cost issues, a treaty in effect that says a country is ultimately responsible for any private enterprise or citizen's activity in space.  That makes most private activities stillborne.

I am two-minded about Mars, although I do believe humans have to go Mars and else place (Grissom's words come to mind as one motivation, admittingly.) if we are serious about the space effort.  But NASA is definitely the most inefficient single airline to do that.



Posted by: cxt217 at March 14, 2008 07:13 AM (iMtMP)

11 There's also the issue that there's no legal settlement for ownership of offworld territory.  That will probably take somebody with "more money than sense" to take a gamble, claim a plot, and force governments to either come to an agreement or de facto acknowledge their claim.

Posted by: BigD at March 14, 2008 07:21 AM (JJ4vV)


I believe it was that treaty that created the blank space regarding how off-world ownership is handled.  From what I remember reading about the treaty, the national liability essentially prevents private ownership because it was the nation, not the person or entity staking the claim, that actually and ultimately had responsibility for it.  No doubt Moscow was quite happy when that treaty came through.


Posted by: cxt217 at March 14, 2008 12:15 PM (iMtMP)

13 Well, "possession is nine tenths of the law."

Posted by: Steven Den Beste at March 14, 2008 01:47 PM (+rSRq)

14 Either CSS is broken, or balace of div's and p's is. My comment is shown with line breaks as-is, no br/ elements. But this would only work if only an equivalent of pre was in force. But more importantly, the bottom of the page is not formatted it all, I see everything raw starting adter the word "entry" right below "Powered by Minx". There's even a closing tag of a comment (dash-dash-more) dangling in the open.

Posted by: Pete Zaitcev at March 14, 2008 06:40 PM (qNSKg)


Your original comment was trashed because the processing code used by the entry box wasn't running when you typed it. Nothing can be done about that.

It didn't turn it into "pre". What it did was turn it into raw text without any markup, which means that line breaks were ignored by the browser when it was formatted.

The javascript file in question does things like this: "Aha! The user just hit "enter". That means he wants what just came before to be a paragraph, so I'll just toss in <p> and </p> tags around it so it'll display properly later." That didn't happen for you.

If you look at the page source, you'll see that your line breaks are present in that comment, where you wanted them. However, because there's no mark-up, because the appropriate javascript file didn't properly load during that session to add the markup where you entered line breaks, those line breaks have no effect on how your comment is displayed now.

The problem is yours, and yours alone, and probably can be fixed by clearing your browser cache and reloading. Then that javascript file will (we hope) load properly and your future comments will be formatted correctly. That won't fix the existing comment, however.

Or the problem is due to you doing something that prevents that javascript from running, in which case you need to figure out what that is and disable it.

Posted by: Steven Den Beste at March 14, 2008 06:53 PM (+rSRq)

16 Just to make something painfully clear: the javascript in question does that formatting when the comment is entered, not when it is displayed.

Posted by: Steven Den Beste at March 14, 2008 06:56 PM (+rSRq)

17 It seems that the fancy editor is not loading for Pete for whatever reason (it only works in Firefox and IE).  By default, the system doesn't convert line-breaks to markup, although it can.

I'm changing the default behaviour so that if there are line breaks, but no markup, it will automatically convert \n to <br>.  That should fix things up.  (There's also a problem with comments imported from Movable Type showing both markup and converted line breaks so that everything is double-spaced; this fix will fix that too.)

Posted by: Pixy Misa at March 14, 2008 08:35 PM (PiXy!)


"That will probably take somebody with "more money than sense" to take a gamble, claim a plot, and force governments to either come to an agreement or de facto acknowledge their claim."

In the words of Leslie Fish, "Queen Isabella, where are you today? The new Chris Columbus is wasting away. The same game is waiting, but no one will play..."

Posted by: Cybrludite at March 14, 2008 09:32 PM (XFoEH)

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