STS Shuttle discussion thread

[Green Baron]

Abstract, please

[PB666]

49 minutes ago, tater said:

I had a love-hate relationship with Shuttle from day one. It was AWESOME to see. I still get goosebumps watching Shuttle launch videos. I've met many Shuttle astronauts, heck, I've driven a bunch of them in my car, had meals with them, etc., and I heard many stories about what it was like aboard. In a sense, I still love Shuttle. But I hate it, too, partially for reasons @PakledHostage has mentioned about some people above. Because of the opportunity cost to NASA. Because it wasn't the holistic system first envisioned, just one part, without any of the other parts (tug, ferry, etc). I hate that it got bloated. I hate that the design was frozen at a point where it was not economical... never the "pickup truck to space" it was pitched as.

I also realize that due to the nature of NASA (and government in general), it could not be evolved in the way it really needed to. It was simply too expensive to change it in a significant way, and likely risk aversion played a role here as well. Any new vehicle faced an STS-1 moment with people riding up something utterly untested, and they chose the devil they knew. I get it, but that doesn't mean I have to like it. As someone who was a space nut in the 70s, and languished waiting on my 2001 future during the 80s, then 90s, and up until the present, I can get a little... opinionated regarding Shuttle. That's not gonna change without a counterfactual history happening .

I don't know about your pickup truck but mine can't carry 11 people and 27,000 kg. But i get the point it tried to do to much, which at times is good, but most of the time it was under-performing its intended function.

You don't have to like its stasis in light of the way everything else is evolving, it should have been a matter that the public had more concern. In a way the shuttle is a victim of its success. The ISS completion is a jump the shark moment, in that it did occomplish its design goal, and we have to remember that the ISS was not waiting on the shuttle, the shuttle was waiting on the ISS. But what nailed its coffin closed was the fact that it had not evolved. ON the day the ISS was completed there should have been a radically evolved shuttle design working . . . .its all management stuff.

But the problem is . . . in hindsight. . . .not the shuttle. The problem is that the system that denied the shuttle its rightful evolution is still around, its still making the same stupid decisions. NASA does pretty well on its small space ventures like the New Horizon and Messanger probes. But the problem the big stuff, like Orion, that stuff is even more problem riddled than the shuttle. For the complexity that the shuttle was relative to 1975 it evolved and was performing quickly (relatively speaking a magnitude faster than Orion), but I see some of the same mistakes of the shuttle going into SLS. And its going to take a company like SpaceX to kick NASA and its contractors in the balls and a tell them that they have to evolve. They have settled into a DoD/NASA sofa and they don't want to risk getting out of that, but they will at somepoint be kicked.

 

[PakledHostage]

1 hour ago, tater said:

Comparing to airliners makes no sense given that airliners are many orders of magnitude safer than Shuttle. 

The Shuttle was also orders of magnitude higher performance than an airliner. My point was that higher performance equipment have slimmer margins, and that that isn't a design flaw - it is the reality of the limitations of physics, material science, etc. The Space Shuttle (like any rocket) was among the highest performance vehicles that have ever existed. Margins are going to be slim, and as we've seen, knowingly operating outside those limits is going to end badly. But again, that isn't a design flaw.

Edited January 17, 2018 by PakledHostage

[PB666]

1 hour ago, GoSlash27 said:

PB666,

"Here in the real world", the shuttle program was retired because NASA deemed it too unsafe to fly. Period, full- stop.
Furthermore, I've grown tired of your unwillingness to maintain a respectful tone when everyone else here is doing their best to be civil and polite despite their disagreements.
 Do me a favor and please refrain from addressing me anymore until you decide to do so in a civilized manner.

Please and thank you,
-Slashy

It was retired after it completed its primary (1970ish) objective to build a space station, the intangible cost of the accidents hurt its survival.

There are two issues, we wanted to support RSA by providing them the crew contract.
And there was the management issues.

2 minutes ago, PakledHostage said:

The Shuttle was also orders of magnitude higher performance than an airliner. My point was that higher performance equipment have slimmer margins, and that that isn't a design flaw - it is the reality of the limitations of physics, material science, etc. The Space Shuttle (like any rocket) was among the highest performance vehicles that have ever existed. Margins are going to be slim, and as we've seen, knowingly operating outside those limits is going to end badly. But again, that isn't a design flaw.

In terms of miles flown, despite the speed of an orbiter, a 747 outperforms, particular when we consider miles traveled in non-inertial reference planes, because these are the miles that age vehicles. The 747 for instance cannot land with a full load of fuel, the V land is too high and the descent angle is too great for its gear. It certainly had better performance than some 1920 and 1930 era commercial aircraft.

[tater]

2 minutes ago, PB666 said:

I don't know about your pickup truck but mine can't carry 11 people and 27,000 kg. But i get the point it tried to do to much, which at times is good, but most of the time it was under-performing its intended function.

I didn't come up with the pickup analogy, someone in government did. My land rover holds 7 people, though (not bad).

The largest mass payload for Shuttle was Chandra, at 22 tons, BTW.

2 minutes ago, PB666 said:

You don't have to like its stasis in light of the way everything else is evolving, it should have been a matter that the public had more concern. In a way the shuttle is a victim of its success. The ISS completion is a jump the shark moment, in that it did occomplish its design goal, and we have to remember that the ISS was not waiting on the shuttle, the shuttle was waiting on the ISS. But what nailed its coffin closed was the fact that it had not evolved. ON the day the ISS was completed there should have been a radically evolved shuttle design working . . . .its all management stuff.

ISS was busy work for Shuttle, like DSG is planned busy work for Orion and SLS. They had a vehicle, and needed to do something with it. To their credit, they managed a nice launch cadence (even if slow compared to what they imagined at the start, it will grossly exceed what SLS will ever do, and for similar money inputs (SLS is a disaster compared to Shuttle, honestly).

2 minutes ago, PB666 said:

But the problem is . . . in hindsight. . . .not the shuttle. The problem is that the system that denied the shuttle its rightful evolution is still around, its still making the same stupid decisions. NASA does pretty well on its small space ventures like the New Horizon and Messanger probes. But the problem the big stuff, like Orion, that stuff is even more problem riddled than the shuttle. For the complexity that the shuttle was relative to 1975 it evolved and was performing quickly (relatively speaking a magnitude faster than Orion), but I see some of the same mistakes of the shuttle going into SLS. And its going to take a company like SpaceX to kick NASA and its contractors in the balls and a tell them that they have to evolve. They have settled into a DoD/NASA sofa and they don't want to risk getting out of that, but they will at somepoint be kicked.

 

NASA will always have the same problems that other government institutions have, they are slow to steer, and lag technology curves (rightfully in many cases, the projects are expensive, and lives are literally on the line).

 

4 minutes ago, PakledHostage said:

The Shuttle was also orders of magnitude higher performance than an airliner. My point was that higher performance equipment have slimmer margins, and that that isn't a design flaw - it is the reality of the limitations of physics, material science, etc. The Space Shuttle (like any rocket) was among the highest performance vehicles that have ever existed. Margins are going to be slim, and as we've seen, knowingly operating outside those limits is going to end badly. But again, that isn't a design flaw.

I don't disagree. In the case of the foam on the ET, however, the performance limitation was ET mass. Because the ET made it almost to orbit (and could have made orbit), every kg of tank mass is a kg of payload lost. Hence the constant rework of the ET to reduce mass (they trimmed many tons of mass off it, amazingly). I think the failure was that they didn't address safety in those changes. Most of the mass savings on the ET was in the metal work. I think that they would have been better served to take much of the ET mass savings, and "spend" that on covering the foam (or replacing it with something else). Yes, they would have lost payload mass. We'd have had a huge cargo bay that could only carry 15 tons instead of 22+. So what. We'd also have 7 astronauts still alive, and perhaps a more sustainable Shuttle program that might have continued, or evolved a 2.0 version.

[PakledHostage]

5 minutes ago, PB666 said:

 The 747 for instance cannot land with a full load of fuel, the V land is too high and the descent angle is too great for its gear. It certainly had better performance than some 1920 and 1930 era commercial aircraft.

But again, that makes my point. The mundane little 747 and many other transport category aircraft can't safely land above their maximum landing weight or you'll risk bending or breaking something, or worse. Those machines have operating limits that are the result of physics, materials science, etc; those operating limits aren't design flaws. 

[tater]

1 minute ago, PakledHostage said:

But again, that makes my point. The mundane little 747 and many other transport category aircraft can't safely land above their maximum landing weight or you'll risk bending or breaking something, or worse. Those machines have operating limits that are the result of physics, materials science, etc; those operating limits aren't design flaws. 

Parts of the craft breaking off every flight that are capable of fatally wounding it is a design flaw.

[PB666]

19 hours ago, tater said:

Idon't disagree. In the case of the foam on the ET, however, the performance limitation was ET mass. Because the ET made it almost to orbit (and could have made orbit), every kg of tank mass is a kg of payload lost. Hence the constant rework of the ET to reduce mass (they trimmed many tons of mass off it, amazingly). I think the failure was that they didn't address safety in those changes. Most of the mass savings on the ET was in the metal work. I think that they would have been better served to take much of the ET mass savings, and "spend" that on covering the foam (or replacing it with something else). Yes, they would have lost payload mass. We'd have had a huge cargo bay that could only carry 15 tons instead of 22+. So what. We'd also have 7 astronauts still alive, and perhaps a more sustainable Shuttle program that might have continued, or evolved a 2.0 version.

See my long read, NASA could have built a new version of the shuttle with carbon-fiber, lowering its mass, they could have redone the computer system lowering its mass. The three SSME could have been replaced with smaller engines and a couple of redundant common turbopumps and done say nine engines in which they never rebuilt engines, use the shuttle 10 times, then evolve a new shuttle. The problem is that you can't evolve anydirection under slow guidance.

19 hours ago, PakledHostage said:

But again, that makes my point. The mundane little 747 and many other transport category aircraft can't safely land above their maximum landing weight or you'll risk bending or breaking something, or worse. Those machines have operating limits that are the result of physics, materials science, etc; those operating limits aren't design flaws. 

Its worse than that on most runways you will run off the ends above 170 kts. Thats essentially the Concorde problem, runways are 2.2 miles long at their longest and once you break 175 kts you are in full commit no matter the craft. But yeah you can run the 747 into the dirt and the stress will likely LOAF the craft.

Edited January 18, 2018 by PB666

[mikegarrison]

I don't understand why people seem so sure SLS will actually ever fly.

[PakledHostage]

5 minutes ago, tater said:

I don't disagree. In the case of the foam on the ET, however [snip]

We got onto the topic because people (including yourself) were brushing over the faulty management decision to launch Challenger, despite the protests of the engineers (who's job it was to define the safe operating limits) that the launch would be unsafe. 

[tater]

Evolution under the right sort of program management would certainly have been possible, though as I said, the design footprint likely stays constant (vertical integration in the VAB means that the place is custom fitted to every vehicle so assembled, at great cost/time).

Clearly, however, they did not recognize the risk until Columbia. As I said above, the program director continued to say it could not have been foam---until they did the tests and demonstrated that foam punches holes in Shuttle at those velocities. They did observe the foam problem earlier, however, as well as many tiles lost per flight.

4 minutes ago, PakledHostage said:

We got onto the topic because people (including yourself) were brushing over the faulty management decision to launch Challenger, despite the protests of the engineers (who's job it was to define the safe operating limits) that the launch would be unsafe. 

Others, maybe, but I said to forget Challenger, as that accident was the result of decision making and easily fixed via launch procedure changes (don't operate in X temp regime).

I wasn't brushing over it, I was saying that the foam issue was a design flaw, and was known from the very first flight, and not addressed (and then not definitively) until after the loss of Columbia.

EDIT: I did say that the SRBs could have obviated the Challenger problem if the side boosters had been chosen based on what was best, not what was politically best. My bad for forgetting.

Edited January 17, 2018 by tater

[PB666]

9 minutes ago, PakledHostage said:

We got onto the topic because people (including yourself) were brushing over the faulty management decision to launch Challenger, despite the protests of the engineers (who's job it was to define the safe operating limits) that the launch would be unsafe. 

See my long read, I replace Tater's design flaw with a design oversight. They did not consider the issue of ice formation on the foam as seriously as they should have, the shuttle functioned because of this for a comparable safety issue I will refer you to this article. https://en.wikipedia.org/wiki/De_Havilland_Comet

IN this case it was a small oversight in the structure that no-one foresaw that overtime crippled a very decent piece of technology. It was way ahead of its time, but that comes with trade-offs with regard to trail blazers.

Edited January 17, 2018 by PB666

[magnemoe]

3 minutes ago, PakledHostage said:

The Shuttle was also orders of magnitude higher performance than an airliner. My point was that higher performance equipment have slimmer margins, and that that isn't a design flaw - it is the reality of the limitations of physics, material science, etc. The Space Shuttle (like any rocket) was among the highest performance vehicles that have ever existed. Margins are going to be slim, and as we've seen, knowingly operating outside those limits is going to end badly. But that isn't a design flaw.

This is why you need an launch abort system, and that is why fighter jets has ejection seats, most ejections has been done in peacetime. (an guess but can bet a lot on its true)
main jarring thing about BFR (ITS) is the lack of abort system, its the same issue as the shuttle. it don't need to be perfect but you want some system. 

 

[PB666]

2 minutes ago, magnemoe said:

This is why you need an launch abort system, and that is why fighter jets has ejection seats, most ejections has been done in peacetime. (an guess but can bet a lot on its true)
main jarring thing about BFR (ITS) is the lack of abort system, its the same issue as the shuttle. it don't need to be perfect but you want some system.

If they had used LFRs instead of SFRBs this would not have been a problem, IMO. There is always going to be risk in space flight, you just don't want to take stupid risks.

[tater]

Yeah, that's my issue with BFS as a sort of modern Shuttle analogy. Cargo is the first version they want to try (sensibly), and while I think the crew version is cool, there is simply no reason for the crew capacity SpaceX shows any time in the foreseeable future. Given realistic crew levels for anything they might attempt (accept for argument that it flies in something even close to Musk's notional timeline), there is no reason for the all crew, with flat cargo version, and every reason for a crew pod (with LES) on top, then whatever cargo below. It does what they show it doing (moon base, whatever), but the few crew needed have an abort mode. With a hatch in the heatshield  of that crew pod, they could still have more crew room below that, giving the crew plenty of space, while still delivering more cargo.

[PB666]

34 minutes ago, tater said:

The largest mass payload for Shuttle was Chandra, at 22 tons, BTW

27027 was the lowest Earth orbit maximum . . .and its one of those stats that in detail is not that meaningful. It also never had 11 people either. In my mind you only need a pilot and two engineers for what ever you want to build, unless you are building 24/7 then you need 6 engineer/technicians and 1 pilot.

28 minutes ago, mikegarrison said:

I don't understand why people seem so sure SLS will actually ever fly.

It will fly, most likely, then be mothballed.

[tater]

STS-27 had 700 damaged tiles, and a near burn through due to tile damage from a foam strike. Mike Mullane (on that flight) is a neighbor of a friend of mine, and I've talked to him a few times randomly. Next time I see him, I'll ask about tile damage, the other times I was honestly just stoked to be talking to an astronaut, lol.

Also, looking up some Shuttle near miss incidents, STS-8 had a near burn trough on the SRB o-ring, and that was a launch in August. Pretty sure temp was not a problem in August, in FL. -51C had a similar issue to the fatal Challenger incident (the following January launch), but it didn't burn through. So the O-ring issue is likely complicated.

[PB666]

1 minute ago, tater said:

STS-27 had 700 damaged tiles, and a near burn through due to tile damage from a foam strike. Mike Mullane (on that flight) is a neighbor of a friend of mine, and I've talked to him a few times randomly. Next time I see him, I'll ask about tile damage, the other times I was honestly just stoked to be talking to an astronaut, lol.

Also, looking up some Shuttle near miss incidents, STS-8 had a near burn trough on the SRB o-ring, and that was a launch in August. Pretty sure temp was not a problem in August, in FL. -51C had a similar issue to the fatal Challenger incident (the following January launch), but it didn't burn through. So the O-ring issue is likely complicated.

Quote

in September 1971 discussed the safety record of solid rockets. While a safe abort was possible after most types of failures, one was especially dangerous: a burnthrough by hot gases of the rocket's casing. The report stated that "if burnthrough occurs adjacent to [liquid hydrogen/oxygen] tank or orbiter, timely sensing may not be feasible and abort not possible", accurately foreshadowing the Challenger accident. - wikipedia

The challenger report and the following observations of SRBs retrieved from the Atlantic that penetration of the O-rings by sea water was not rare. The challenger was unlucky in the sense that the burn through pointed right at the 12 strut. That was what caused rapid progression. Following the accident investigation MT was to report any unusual activity with the O-rings, prior to that there was not a priority on reporting unexpected behavior. I believe in one report they found that the seat for the O-ring had not been properly seated because it was not properly cleaned.

http://www.thecrimson.com/article/1986/12/10/morton-thiokol-getting-off-easy/
https://www.nasa.gov/centers/langley/news/researchernews/rn_Colloquium1012.html

 

Quote

Evidence of serious O-ring erosion was present as early as the second space shuttle mission, STS-2, which was flown by Columbia. Contrary to NASA regulations, the Marshall Center did not report this problem to senior management at NASA, but opted to keep the problem within their reporting channels with Thiokol. Even after the O-rings were redesignated as "Criticality 1"—meaning that their failure would result in the destruction of the Orbiter—no one at Marshall suggested that the shuttles be grounded until the flaw could be fixed - https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster

Quote

Boisjoly wrote a memo in July 1985 to his superiors concerning the faulty design of the solid rocket boosters that, if left unaddressed, could lead to a catastrophic event during launch of a Space Shuttle. Such a catastrophic event did occur less than a year later resulting in the Space Shuttle Challenger disaster. - https://en.wikipedia.org/wiki/Roger_Boisjoly

X

Quote

By 1985, with seven of nine shuttle launches that year using boosters displaying O-ring erosion and/or hot gas blow-by,^[11] Marshall and Thiokol realized that they had a potentially catastrophic problem on their hands. Perhaps most concerning was the launch of STS-51-B in April 1985, flown by Challenger, in which the worst O-ring damage to date was discovered in post-flight analysis. The primary O-ring of the left nozzle had been eroded so extensively that it had failed to seal, and for the first time hot gases had eroded the secondary O-ring.^[12] They began the process of redesigning the joint with three inches (76 mm) of additional steel around the tang. This tang would grip the inner face of the joint and prevent it from rotating. They did not call for a halt to shuttle flights until the joints could be redesigned, but rather treated the problem as an acceptable flight risk.

.

Quote

The matter was discussed with Morton Thiokol managers, who agreed that the issue was serious enough to recommend delaying the flight. They arranged a telephone conference with NASA management and gave their findings. However, after a while, the Morton Thiokol managers asked for a few minutes off the phone to discuss their final position again. Despite the efforts of Boisjoly and others, such as Bob Ebeling, in this off-line briefing, the Morton Thiokol managers decided to advise NASA that their data was inconclusive. NASA asked if there were objections. Hearing none, the decision to fly the ill-fated STS-51-L Challenger mission was made.

So basically it was not just temperature drops, but windsheer could cause the joint sections to roll and open up a gap (gaps with hot gas instantly degrade the rings causing blow through.

According to the experts at MT it was the low temperatures that opened the O-rings that grease later sealed (they expected challenger to blow up on the launch pad) but then a wind sheer rolled the joint and the heat and the roll allowed the grease to push through creating a blow hole.

But this is old hat, why is  SLS using essentially the same type of booster?

 

[tater]

13 minutes ago, PB666 said:

"Criticality 1"—meaning that their failure would result in the destruction of the Orbiter

Note that this underlines the fact that any separation event while the SRBs were operating was a certain failure of the orbiter due to aerodynamic forces.

15 minutes ago, PB666 said:

But this is old hat, why is  SLS using essentially the same type of booster?

Because it's "cheaper" to use existing Shuttle technology. Or something. For reasons.

Or they wanted votes from Utah.

[Starman4308]

1 hour ago, PakledHostage said:

We got onto the topic because people (including yourself) were brushing over the faulty management decision to launch Challenger, despite the protests of the engineers (who's job it was to define the safe operating limits) that the launch would be unsafe. 

A faulty management decision that only killed astronauts thanks to a faulty design that had no abort mode for much of the ascent.

That the managers messed up does not absolve the design's failure to have a robust abort mode on an experimental craft. Granted, the Shuttle was halfway designed by the managers, with the engineers just doing what they could under far too many demands.

[sevenperforce]

8 minutes ago, tater said:

Note that this underlines the fact that any separation event while the SRBs were operating was a certain failure of the orbiter due to aerodynamic forces.

Because it's "cheaper" to use existing Shuttle technology. Or something. For reasons.

Or they wanted votes from Utah.

Because at one time, it made sense to continue building SRBs and ETs, slap an interstage adapter on the top of the ET and a thrust frame on the bottom, and fly expendable. See DIRECT/Jupiter.

"But Constellation!" they said. "But Altair!" And so THAT happened.

 

Random: has an operational LAS ever been used for a cargo launch?

[DerekL1963]

I have always found it interesting that Shuttle's inherent safety flaws are brought up - but never those of Soyuz.  I doubt many people are even aware of those flaws, let alone the fact that they've lead to three in-flight accidents.

As Pakled said, this isn't a discussion of engineering or reality...  it's a theological debate.
 

53 minutes ago, tater said:

Also, looking up some Shuttle near miss incidents, STS-8 had a near burn trough on the SRB o-ring, and that was a launch in August. Pretty sure temp was not a problem in August, in FL. -51C had a similar issue to the fatal Challenger incident (the following January launch), but it didn't burn through. So the O-ring issue is likely complicated.

Yup.  Very few of Shuttle's detractor know anything beyond "Cold is Bad Cold is Bad Cold is Bad".  And only having a cargo cult view of the situation, they don't realize the worst burn through incidents (prior to Challenger) all occurred at temperatures well within the "safe" range.  Nor do they realize that the "engineers issuing warnings" were a small handful at the last moment.  Which is why management, not entirely without cause, distrusted them - despite the multiple prior burn through events, they'd been repeatedly told it was safe to continue to fly.  (A pattern that would be repeated when it came to the foam strikes and Columbia.)

The key safety problem with the Shuttle wasn't it's design, low margin high performance vehicles are always risky.  It wasn't directly people, engineers or management.  It was a culture that encouraged myopia and the belief that since they'd gotten away with it so far, they would continue to do so into the future.

13 minutes ago, Starman4308 said:

Granted, the Shuttle was halfway designed by the managers, with the engineers just doing what they could under far too many demands.

All vehicles are designed by managers with engineers doing the best they can to juggle all the requirements placed on them, even when the requirements are contradictory.

[tater]

Yeah, the safety (or concerns) with Soyuz never seem to be figured in. The question for Commercial Crew is not really, "Does CST-100 or D2 meet the arbitrary LOC statistical requirements?" but rather, "Is either vehicle at least as safe for our crew as Soyuz?"

I do find it interesting that Atlas is assumed 100% safe for CST-100 (great launch record, to be sure), but they will fly with a version of centaur that has only flown once I think (or is it not at all, but after the unmanned test flight it will have flown once?).

The COPV concern with F9 S2, OTOH, has flown with the fix in place for every single S2 since return to flight.

I still think that the foam issue was non-trivial. I'm honestly not sure what the trade offs would look like to eliminate it as a problem. Skinning the ET in Al would have been a huge mass penalty, and indeed might have made Shuttle not really useful, I honestly don't know. I do know that the foam was a problem, and the fixes mostly involved attempts to mitigate it via spray technique. Sometimes expanding urethane foam sticks tenaciously to itself (previous layers), and other times it diesn't stick at all, and entirely delaminates on interfaces. It's really touchy about technique, as well as mix ratios---and humidity.

[mikegarrison]

17 minutes ago, tater said:

I do find it interesting that Atlas is assumed 100% safe for CST-100 (great launch record, to be sure), but they will fly with a version of centaur that has only flown once I think (or is it not at all, but after the unmanned test flight it will have flown once?).

The dual engine centaur has flown before, but never with an Atlas V.

[tater]

OK, looks like it has already flown just once for the Echostar-7 launch in 2002 on an Atlas IIIb-DEC. Incremental changes in F9 require a gelled design to fly 7 times before they will certify it, changes in Atlas? Not any flights at all.