GoSlash27

No, I won't. Judging by the hostility in your posts, I don't think that I'm the one whose judgement is clouded by emotion. Rude... The entire layout was a flawed concept. The engineers and technicians did an outstanding job making it work, but it was a fundamentally unsafe design.

All true, but that problem stretched far beyond the go/ no go decision of Challenger. It affected the entire design process of the STS itself.

KerikBalm, A critical piece of information is that our .gov won't divulge which department ZUMA belongs to. That is critical because it's such a rare occurrence. The only department that is known to have done this in the past is NSA, so that points to the most likely mission as NSA SIGINT sat. Best, -Slashy

'Zackly. But it turned out that reuse was a bad assumption for the available tech, just like with the SRBs. None of it panned out, it just made the whole thing a lot more expensive and dangerous. Best, -Slashy

tater, I agree with all this last, but I'd argue that the *real* problem was the assumption that refurbishing the main engines was economical enough to warrant all of this trouble. Imagine how much more reliable and economical the entire program would've been had they decided to treat the core stage as disposable. There would've been no need for a RV that glides home with RCC tiles, no side mounting, none of it. Best, -Slashy

a) arguable. The people who made those decisions weren't engineers. They were lawmakers and bureaucrats. b) false. c) Is closer to the truth, and directly contradicts b. Best, -Slashy

Agreed. And both could have been prevented by not having an airliner with all of the structural integrity of a soap bubble strapped to the side of an assembly with the chemical energy of a tactical nuke with no abort modes. Best, -Slashy

Indeed. Possibly the most amazing feat of engineering in history.

No, it is objective fact. If the crewed return vehicle is on top of the stack, then chunks disintegrating or falling off of the stack aren't going to destroy it. If it's on top of the stack, then it can be aborted with the crew throughout the launch and can be expected to reenter intact. The design *itself* was fraught with peril.

PB666, Oh, no. The general design was indeed bad. It was disappointingly bad from a cost- effectiveness perspective and appallingly bad from a safety perspective. All of the safety problems that were unique to the shuttle have been repeated ad nauseum upstream and I won't bother to rehash them here, but they *all* stem from having the (incredibly fragile) crewed reentry vehicle on the side of the stack instead of on top. A lot of failure modes that could only happen because the crewed reentry vehicle was where it was, and a lack of abort options because the crewed reentry vehicle was where it was. There were many things they could have done to reduce the risks, but nothing could have been done to make it *as* safe as a conventional design. Best, -Slashy

mikegarrison, I agree with the safety mentality angle, but only in as far as they actually man-rated a launch vehicle that had the crewed reentry vehicle on the side instead of on top. All the other safety hazards stem from that fact. They could've mitigated the risks somewhat, but there's nothing you can do with that layout that's ever going to make it as safe as a more conventional layout. Best, -Slashy

^ Agreed. The only practical application in KSP for an SSTO spaceplane is to get your payload to orbit as cheaply as possible. Since the only expenditure is fuel, efficiency is measured by how much fuel is expended per tonne of payload. Going with a higher t/w may reduce your fuel expenditure faster than it reduces your payload capacity, saving you both time and money. The most cost effective SSTO spaceplanes I've seen had roughly twice as much engine as they actually needed. Best, -Slashy

xlm, It's the atmosphere that makes it impossible to calculate precisely. For an airless body the process is much more straightforward: Calculate Vorb at sea level, add the DV to transfer to desired orbital altitude, and subtract the planet's rotational velocity. For an airless Kerbin, sea level Vorb is 2,426 m/sec. Hohmann transfer to 70km is another 130 m/sec. Kerbin's rotation is 175 m/sec. So theoretically the minimum DV is 2,381 m/sec. But you have to follow a gravity turn to keep out of the denser part of the atmosphere, you have gravity losses and drag losses. All this together makes 3,400 m/sec about normal for a launch. Best, -Slashy

^ This, and a lot of the other missions were merely sending crews up to the ISS on an outrageously- dangerous and expensive platform because it was the only one we had at the time.

Right, but conversely nobody ever said "well, we were *gonna* do this, but the shuttle's gone and now we can't". So... not really missed. I mean... there was never a backlash in the scientific community saying they need a shuttle, even when it was being shut down. So in the last 6 1/2 years, how critical was it really? I don't think it was critical at all. Best, -Slashy

^ Tenuous at best. There were no material tests I'm aware of that NASA wanted to do but couldn't. Certainly none that they would've risked a whole crew for, spent a billion dollars, and definitely couldn't do at the ISS.

mikegarrison, I think you've just answered your own question here. In the very narrow scope of my comment, the question is "between July 21st 2011 and today, did NASA have any planned or desired missions that had to be scrapped because the shuttle was no longer flying at the time"? I'd say the answer to that is no, but if I'm mistaken I'm sure that somebody will correct me. In the last 6 1/2 years, NASA has done what it intended to do without the services of the shuttle. Therefore it was not necessary in the interim. In the case of past missions which required the unique abilities of the shuttle, I'm glad we had those abilities and I'm thankful for what it has provided. In the hypothetical future missions where a shuttle *might* prove helpful, I'm sure that the retired STS program would not have been considered a viable option anyway. We'd either find another way to get it done or simply not do it before considering using a mothballed highly sketchy vehicle with a billion dollar price tag per launch and heavy risk to human lives. If worst comes to worst, we'd build a new fleet of markedly improved shuttles. I see the comparison to Apollo as highly appropriate in that sense. It did what we needed it to do, and we didn't need it for the jobs we did afterwards. Best, -Slashy

They made it abundantly clear what their motive was: They were convinced that the Shuttle was going to get somebody killed if they continued flying it. As for Orion, it's not intended to be a replacement for the Shuttle.

I'm looking forward to it. In the meantime, NASA has successfully accomplished everything it might've otherwise used the shuttle to do, spent less money, and nobody got killed in the process. I call that a win. Your mileage may (and clearly does) vary. Best, -Slashy

Well, they can't. That option is no longer on the table. Cooler heads prevailed, and the majority here agrees with that decision.

Jaff, Good question. I'm not sure that it was an option. The mounting points would be under tremendous load and there's the problem of how the shuttle/ stack would behave. Maybe they thought it was a better gamble to hope it held together? Best, -Slashy And your philosophy is why you're not in charge at NASA

Yeah, and sometimes it doesn't have to be and you make it easier when you can. Still not a persuasive argument.

All due respect, but I believe you are the one who is struggling with this concept. If you have a choice of ways to complete a job and one is inherently safer and more economical, then that's what you go with. You don't just shrug off the unnecessary hazard and cost by shrugging and saying "life is hard, suck it up". I find this argument completely unpersuasive and more than a little callous. Best, -Slashy

How would that happen? There's no way for a top mounted capsule to be anywhere near a failing SRB seal. *Especially* not a Soyuz. Best, -Slashy

Leafbaron, Yeah, there's that, too. I use spaceplanes to lift "stuff" and boosters to lift "things". Boosters are a lot more tolerant of size/ shape variations of their payloads. Spaceplanes make nice containers for supplies and crew that must be transferred across docking ports. Also... I like to use the payload to help itself to orbit whenever possible. If it has fuel tankage, I'll use that to feed the stack. If it has engines, I'll use them on the way up, etc. It's very economical to refuel something in orbit using spaceplanes. Best, -Slashy