posted
Er...the shuttle's record on actually (safely) inserting satelites is near 100%.
Rocket delivery....not so good. Spaceprobe delivery: far far worse.
Of course the shuttle is financially impractical for most companies to use as their deployment system...but that could (really should have already) change.
I recall that prior to the Challenger disaster, the shuttle went up pretty regularly with commercial payloads.
And government deathrays. We must not forget the non-existant SDI weapons platforms that kept the world safe from the Red menace.
-------------------- Justice inclines her scales so that wisdom comes at the price of suffering. -Aeschylus, Agamemnon
Registered: Aug 2002
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posted
First of all, according to some NASA answer-man, there have been something like 4,000 satellite launches since satellites were invented. The subset of those launched by space shuttle is, as one might imagine, significantly smaller. That the shuttle is more reliable is not something I'm disputing, but how expensive is that reliability?
According to some dude on the internet (well, military historian James Dunnigan) the shuttle's launch costs for satellites run around twenty-five million dollars per ton, versus, at the lowest end of the scale, three million dollars. How much does it cost you to develop New Satellite X? (This isn't taking insurance into account, which the linked article does; in fact, it comes down in favor of the shuttle, sort of.) My point isn't that some particular rocket is better or even cheaper than the shuttle; simply that unmanned rockets in general can do almost everything the shuttle does in terms of payloads with only slightly less reliability and at much lower costs.
And as for "spaceprobe delivery," I'm not quite sure what you're talking about. "Spaceprobes" don't launch satellites, for one thing; but I am guessing you're refering to the number of Martian probes lost, the majority of which were lost at Mars, making me wonder what delivery systems have to do with it.
((How many interplanetary probes has the shuttle launched, anyway? Galileo, and. . . ? I can't seem to find a simple list of both probes and their launch vehicles. Anyway, not many, compared, again, to the number of launches in total.))
Registered: Mar 1999
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posted
i was not really touting the shuttle as a spaceprobe delivery system: I was more poking a stick at rockets reliability by mentioning them.
It's probably just really bad luck, but there's been a lot of cringeworthy moments as some new and imporntant probe went down in flames with it's rocket.
Though (as you brought it up) I'd think the shuttle could fill a vital role in deploying spaceprobes. I dont know how dangerous it would be, but the shuttle's cargo bay could probably hold a small rocket with a probe attached to the top.
Heck, if they could just remotely pilot the shuttle's boosters and fuel tank, they could put damn near anything they wanted into orbit!
Imagine the telescope that could be launched if the payload was that of a fully-loaded space shuttle.
Biiiig.
Mabye there is a way to have the shuttle randevous with space-based fuel tanks (launched by remote rockets for safety reasons) so it's effective ange is extended.
I'd dearly love to see a telescope placed on the moon's far side.
Of course if they can get this to really work, then the shuttle's cargo capacity would become chump change.
Though I worry that there are no real guidelines for the waste that rockets (and the shuttle itself, I suppose) accidentally place into orbit.
Mankind may one day be planetbound by a prison of high-velocity space junk. Keeps them aliens out though!
-------------------- Justice inclines her scales so that wisdom comes at the price of suffering. -Aeschylus, Agamemnon
Registered: Aug 2002
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posted
You may want to recheck your numbers on the Shuttle's cargo capacity vs. the Ariane 5-ECA. Price? You get no argument. Capacity? You will. Now if you could get a two-stage Energia to work on a commercial schedule, you'd really have something. Buran's only orbital flight was entirely remote controlled.
For some time there had been talk of putting some little OMS boosters on the External Fuel Tanks to lift them into orbit for use as I dunno what. Those would probably make for great junk sweepers.
quote:Jason Abbadon was all: I'd dearly love to see a telescope placed on the moon's far side
posted
I dont think they even have a blueprint or the proposed Webb telescope, much less the required funding or construction teams. Nice dream though: mabye China will get to it.
-------------------- Justice inclines her scales so that wisdom comes at the price of suffering. -Aeschylus, Agamemnon
Registered: Aug 2002
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Also: refueling the shuttle in orbit: impossible. Once again, this simply isn't something it is designed for.
And: I read a neat proposal for using the external fuel tanks as habitat modules for a space station on the cheap. (Though it was light on the details.)
And: launching things with rockets on them is one of the reasons the shuttle's payload bay looks like it does. That's in the design specs. I already mentioned Galileo. The problem, of course, as in all things, is that the shuttle is not an order of magnitude better at that sort of thing than other launch systems.
Registered: Mar 1999
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posted
The shuttle seems safer though for some things: fragile communications equipment in particular (though that has come a loong way since the shuttle's heyday of satelite delivery).
You'd think there could be some sort of physical pump that could get fuel from an orbiting tank into the shuttle (image of how a syringe pushes liquid through a needle).
-------------------- Justice inclines her scales so that wisdom comes at the price of suffering. -Aeschylus, Agamemnon
Registered: Aug 2002
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posted
Incidentally if they were talking about ordering the mirror segments for Webb in 2003, that's a bit further along than sketches on napkins.
Getting a loaded external fuel tank into orbit would pretty much be impossible. Or at least very difficult. OTOH, I can't imagine that refueling the hydrazine tanks of the OMS and RCS systems would be all that insurmountable and I seem to recall something about one of Freedom's roles was going to involve being a SSO gas station. As it is they use Helium very much like your syringe idea, Jason. The question is what kind of range would that give you? I'm not certain, but I doubt even fresh tanks would get you very far beyond a geostationary orbit. Also keep in mind that it's a very small cabin. I think the longest shuttle flight was something like 3 weeks. There's a reason for that.
Of course if you specially modified one shuttle and took up a quarter (or half?) of the payload bay with a tank, you might have a highly capable lunar orbiter. You'd need to have a good reason to do this, of course. Other than giving future Micheal Collinses someplace more interesting to sit.
Pipedreams aside, I would say a chief feature of shuttle deployment vs. rocket deployment (aside from reliability and the retrieval option Simon mentions) would be the additional troubleshooting potential of a human crew. If, fresh out of the bay, the solar panels (or antenna) on your satellite don't unfurl the way they ought to (and presuming the mission is rigged for EVA), you can have someone go out and yank on stuff. Also for construction on ISS they've already demonstrated that two arms are better than one. (I'm still not entirely clear on how all those trusses go together.) How often have the remote operators of Gallileo or Spirit wished that they could just go over to their toys and fix 'em?
Registered: Sep 2000
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quote:Originally posted by Balaam Xumucane: Incidentally if they were talking about ordering the mirror segments for Webb in 2003, that's a bit further along than sketches on napkins.
-------------------- Justice inclines her scales so that wisdom comes at the price of suffering. -Aeschylus, Agamemnon
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