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Old June 23 2012, 10:57 PM   #153
Crazy Eddie
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Re: SpaceX is a go for April 30th: 1st commercial launch to space stat

publiusr wrote: View Post
"The Senate Launch System is being designed with NO specific mission in mind."

Lunar flybys are going to be one of many missions.
NASA has no lunar flyby mission even in the planning stages that requires SLS. They're in no position to ATTEMPT to plan such a mission since 90% of the components for it aren't even on the drawing board yet (significantly, this includes the Orion's service module).

Well, if this really is the Senate LV as people joke--and they hold the purse-strings (not slide rules--that's MSFC), they will push on
Yes, they'll spend a lot of money building it. That doesn't mean it'll actually DO anything.

The Chinese modules are not really Mir Examples.
Tiangong-1 isn't (more of a slightly scaled-down Salyut). Their plans for Tiangong-2 largely echo the Mir, though even at a slightly reduced size, this is more than can be said for NASA until at least the middle of next decade.

It was abandoning Saturn in favor of STS that really held us back. That and this push for RLVs. You might remember the 1970s Mars missions using Saturn architecture that STS gobbled up. RLVs are the technological pipe dream that has already proven not to work very well.
In the end, so are HLVs, in this case for the same basic reason: overly-optimistic projections of utility and overly conservative projections of risk.

Of particular note is the fact that Skylab entered orbit in a barely-functional state, one solar array lost and the other damaged and inoperable with its sun shield torn off. A team of astronauts had to be sent up to make repairs before the station was even useable; they rode into orbit on a Saturn-IB, NASA's smaller and less expensive medium-lift booster. A Saturn-V would have been massive overkill for a rescue mission to Skylab; more importantly, it probably wouldn't have been ready in time to keep the station's orbit from decaying.

Assuming the hydrogen didn't boil off from the first launches into space--making a case to keep launching?
ISS uses hydrazine for reboost, not LH2. Beyond that, I don't really understand what you're talking about.

Even if it made economic sense to say, cut up the Curiosity rover and launch it on 20 or so Vanguard rockets--is that really the best thing to do?
Probably not. Which is why it's a good thing Curiosity is small enough not to require an HLV to get anywhere.

On the other hand, if you were really strapped for cash you could split a space probe up into 20 parts and ship it to an orbiting space station, have the astronauts assemble it, strap some ion thrusters to it and send it on its merry way. Since you can also certify and test the probe in space BEFORE it leaves orbit, that would further avoid alot of the headaches that have plagued previous since missions (Phobos-Grunt's epic computer fail, or the Cassini's high-grain antenna failing to deploy properly).

The question really is which rocket design gives you more bang for your buck. How much time and money do really save by avoiding in-space assembly? The fact that in-space assembly and in space REPAIR are related tasks -- and the fact that every space station ever flown has required a certain amount of repair/assembly after launch -- are you really saving anything at all?

Or put that another way: if in the 1970s NASA had possessed ONLY the Saturn-V rockets as its sole means of transporting humans into space, would they have been able to salvage Skylab?

"It's the same people who crunched the numbers and figured out that the same money that is being spent on the DEVELOPMENT of the Senate Launch System could just as easily find a hundred LAUNCHES of useful payloads on the rockets we already have."

That was also the arguments of fans of clipper-ships who thought larger steel ships like Great Eastern were a waste.
LOL no it wasn't

Why, you could fund lots of schooners with that money. And you could buy lots of cessnas for the price of a C-5 Galaxy. But that is short sighted.
You're getting your analogies muddled up; in this case, it's more of a C-47 vs. the Spruce Goose. One is a large aircraft that is expected to carry a large amount of cargo at a low cost. The other is a RIDICULOUSLY large aircraft that can carry more cargo than you probably need for more money than you can probably afford.

It'll take a MAJOR technological breakthrough before HLVs become in any way economical for widespread use. SLS, far from being a breakthrough, is actually a rehash of 1970s technology slightly rearranged in a new configuration just to give some aerospace contractors and their pet space capsule something to do with their spare time. It's not even a proper launch vehicle so much as it is a multi-billion dollar nostalgia project.

As it stands, it looks like Shuttle-derived heavy lift seems secure. Obama allowed Bolden and Lori Garver (who wasn't fond of HLLVs, or so scuttlebut has it) to roll out SLS.
"Allowed" isn't the word for it; NASA is required by law to build it. The only constant when it comes to discussing NASA's budget is that Congressional mandates and priories are subject to change without reason or logic.

The good thing is that Falcon's success may erode support for the Ares-I redux that is called Liberty.
There's support for Liberty?
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Last edited by Crazy Eddie; June 23 2012 at 11:08 PM.
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