STS Shuttle discussion thread

[mikegarrison]

2 minutes ago, RCgothic said:

Do you mean shear/extrusion? An o-ring can't have tension in a cross-sectional plane unless it's glued to the sealing surfaces, it would simply lose contact (and not seal).

I mean that the two parts the o-ring seals against should be pressing together in order for an o-ring to work properly. Instead, the two parts in the shuttle pulled away from each other. What actually happened in the prior flights is that the the o-ring slipped out if its groove and jammed itself into the gap. This was not how it was designed to work, but nobody took it seriously and fixed it. They just shrugged it off and said, "huh, looks like this works too". Problem was in the accident flight that it was too cold to slip out of its groove and flow into the gap.

The fix was to put a tang of metal on the inside of the upper ring so that when the cases were pressurized the two sides of the o-ring gap would no longer pull away from each other.

[sevenperforce]

10 minutes ago, tater said:

The tanks are just fuel in this example (McDonnell-Douglas ILRV, 1966)

Bare tanks can be chuted down, but I doubt that leaves you with much payload other than the vehicle itself. Every tonne of engine you move from the orbiter to the drop tanks (making them boosters) is an extra tonne of payload to take into orbit.

Of course, this only works if you go ahead and develop crossfeed...which, in real life, is much more complicated than just enabling the advanced gizmo in KSP. If you want to make it fully recoverable, there's a bit of a tradeoff; you can move engines to the drop tanks and allow them to land propulsively, increasing payload on the orbiter and saving the weight of chutes, or you can just chute the tanks, which hurts payload on the orbiter but means you don't have to reserve landing propellant.

7 minutes ago, PB666 said:

16 minutes ago, sevenperforce said:

If you wanted to build a reusable crew-and-cargo shuttle, today, it would probably come out looking something like this:

  Reveal hidden contents

 

 

Thanks but no thanks, it does not meet any useful requirments.

Wait, what? That architecture does everything the Shuttle could do, plus full recovery, 0-0 abort, and an independent crew capsule lifeboat.

[RCgothic]

13 minutes ago, mikegarrison said:

I mean that the two parts the o-ring seals against should be pressing together in order for an o-ring to work properly. Instead, the two parts in the shuttle pulled away from each other. What actually happened in the prior flights is that the the o-ring slipped out if its groove and jammed itself into the gap. This was not how it was designed to work, but nobody took it seriously and fixed it. They just shrugged it off and said, "huh, looks like this works too". Problem was in the accident flight that it was too cold to slip out of its groove and flow into the gap.

The fix was to put a tang of metal on the inside of the upper ring so that when the cases were pressurized the two sides of the o-ring gap would no longer pull away from each other.

Got you. 

[CatastrophicFailure]

Out of likes already. 

4 hours ago, JEB'S DESTINY said:

They could've made it more safer with ejection seats (Challenger), better external tank (Columbia), and more careful engineering. Overall, the shuttle is one of my favorite spacecraft because it is very specially engineered, and is complicated because of it's moving center of mass.

Also @tater, @sevenperforce, et al: The other problem with ejection seats is that if there’s more than four people flying (and there usually were), the rest are down on the middeck, sandwiched between the flightdeck and many metric craptonnes of fuel. There’s simply no way to get them out of all that structure reliably. Making the whole crew module separate and rocket away was possible, maybe, but you’ve got a lot of hoses, lines, and electrical cables that you’ve got to sever all at once, and it’s got to happen right the first time. And the rest of the orbiter needs to be strong enough to not immediately collapse as you’re trying to get away. 

Heres one concept for a crew escape pod in the cargo bay:

You can see how much space it takes up, I don’t even want to think about how heavy it is. And assuming the docking port is at the top there, you’ve now got two missiles aimed directly at the ISS once docked. How they’d get it through the cargo bay doors, I don’t know. Presumably the flight crew would have had something like these from the B-58 Hustler:

So y’all can see the ridiculous measures needed to try and make a crew “safe” on the side of a rocket. 

4 hours ago, PB666 said:

MOre vaporware

You miss the point, my friend. It’s a thing very similar in design to a space station, doesn’t look that different, planned to be built without a shuttle. 

2 hours ago, sevenperforce said:

giant tubes of bomb

This needs to be the official term from now on. 

 

I was one of those kids who thought NASA could do anything, and then the Challenger blew up in the middle of class. Ever seen a teacher scared before? I mean actually terrified, rushing to turn the TV off? That leaves a mark. 

@mikegarrison learn me something, here, how does a rubber O-ring stop hot exhaust gasses otherwise able to cut through metal struts in the first place? 

[mikegarrison]

The real problem with shuttle safety was not that the orbiter was on the side of the stack. It was not the SRBs. It was not the foam. It was not the lack of a way to repair the orbiter in orbit.

The real problem was NASA had a terrible safety mentality. The learned NOTHING from the first shuttle loss, because they did the EXACT same thing the second time around. When your system is not working as designed, you don't just shrug it off and say, "it hasn't killed anybody yet...." They knew those SRB o-rings were not working as designed, but they ignored it. They knew icy chunks of foam were falling off and hitting the orbiter but they ignored it. There were other problems too, that they ignored. For instance, they knew they lost heat shield tiles every mission, but they never fixed that problem.

In most forms of transport in the US, there has long been an independent safety check. That's what the NTSB is for. It's so that when there is a problem, the same people at the FAA or the FHA or the FRA that approved the design in the first place are not the only people reviewing it. The NTSB can give an independent viewpoint and make their own recommendations. (They aren't always accepted, but that's its own issue.)

NASA, however, didn't have that kind of independent checking. After each shuttle disaster they convened a special board to make recommendations, and then promptly ignored what they had to say and re-did it "the NASA way" anyway.

And as far as I know, there is no reason to think that anything has changed since then.

Edited January 16, 2018 by mikegarrison

[mikegarrison]

42 minutes ago, CatastrophicFailure said:

@mikegarrison learn me something, here, how does a rubber O-ring stop hot exhaust gasses otherwise able to cut through metal struts in the first place? 

It's because of the difference between statics and flow. The gas is light. So even though it is very hot in temperature, it doesn't have a lot of energy in any specific bit of volume. So in a static situation, the gas presses against the seal, gives up its small amount of energy, and then sits there as a barrier protecting the seal from any new gas getting to it. But in a flow situation, new gas is continually pouring through, carrying new energy with it. Those o-rings would slip out of their groove and jam into the gap and cut off the flow, thus cutting off the source of new heat. But on the day of the crash the o-rings were not flexible enough to jump out of their grooves. So lots of flow went past them, all bringing its own new heat, and that quickly destroyed the o-rings.

Then, luckily enough, the aluminum oxides from the SRB combustion coked up in the gap and blocked it themselves. That's the only reason it didn't explode right there on the pad. So again the flow stopped and so did the new source of heat. Sadly, flexing in flight (apparently due to wind shear) broke the brittle plug formed by the aluminum oxide, and then the hot gasses could flow again.

(In more conventional terms: static gas is terribly bad at heat transfer by conduction, but flowing gas is terribly good at heat transfer by forced convection.)

Edited January 16, 2018 by mikegarrison

[PB666]

8 minutes ago, tater said:

Yeah, they'd be huge. A little lost cargo bay payload, but the vehicle was a compromise anyway in that regard. The Shuttle system put well over 100 tons into LEO, it's just that most of the mass was Orbiter. Once the goal (make work) was to make a station, the problem was that you could eliminate 4 launches by making all the parts over 100 tons, and not bother with the orbiter. Something akin to Shuttle C, but where the entire SSME/OMS rear package is dumped, and the "cargo bay" part is replaced with a single, skylab-like station part. An earlied Shuttle C mission could have left a hub, and perhaps a tug part, so that the huge modules are rendezvoused to within X hundred meters, and the tug goes out and brings them in after the engines are gone (that package could deorbit itself).

The tanks are just fuel in this example (McDonnell-Douglas ILRV, 1966)

At least there is one person here thinking about the evolution argument, but in my opinion (n dealing with other posts and getting back to this one at the end) its not about the crew release. Biologically speaking the source of the problem also has to mandate the solution, not the 3rd dependent reaction. As you state the shuttles capabilities are exceptional, just not as efficient as desired.

I say biologically because FIRST the crew has to be in a conscious or mobile state. You can't argue success if three were already unconscious as the moment of force application is completed. So if the state of the system evolves too quickly no crew compartment is going to work thoroughly and if the solution is not going to be complete there is no reason to waste mass to remediate the problem. The problem with the evolution of the STS-51-L is that there was a state that could no longer be contained. Even if one person was conscious there was no way for him to protect the rest of the crew from the effects of decompression, there was no way to alter the shuttles trajectory (other than one-human unit movements) because all of the control features disintegrated. Before we can discuss saving the crew (both in the case of challenger and columbia) we first have to save the orbiter. If the orbiter is significantly torqued to its disintegration point  then its likely you already have dead or nearly dead crew. This is my interpretation of what happened. There was a pressure breach people went for their O2 but there was no means to escape or the crew were not able to escape due to structural criticality. Unless we are talking about launch crew in a 'bug' that they then move to the orbiter after a certain stage is released, there are basically no solutions to this problem. So 7PF does have a minimal point, but then the next flight of the Soyuz could show us a design flaw in their system.

Challenger disaster should not have happened and it was 100% preventable, this does not mean by some other mechanism a similar crisis could occur, but that was the negligent homicide of the crew, a crime that was never prosecuted. If it had been prosecuted our view of the incident may be completely different. Because it wasn't we look at flaws in a system that in reality worked as designed, you don't drive a car off a cliff and say the brakes are broken and you couldn't stop; the time to test brakes is before going over the side of cliff.

That is the initial problem but let me take the devil's advocate and argue that it could have been a completely random occurrence. Im doing this to develop a structural argument for manned space flight that eliminates certain models (i.e the above). So we have to define the what that state was then work to correct it. The initial state is a booster who nominal performance evolved over time along an 'unexpected' tangent (literally there was a tangent exhaust vector to the axial vector) . That tangent interfered with the containment function of the hydrolox tank. There was a domino effect on performance that went critical and standard models of prediction break down because there are forces acting in many directions and damage becomes foggy. So here we have to stop and argue, there is a theoretical crew escape system that would have work, it could be explosive bolts on the crew compartment with a hidden parachute that drops them safely in the Atlantic, the pointy nose should mitigation the impact deceleration. SO we have a handwaving solution. We assume that would stay alive long enough for them to catch their breath or be aided by a crew member.

The problem is this you have torque being applied on two lift surfaces differentially to the point at least one breaks, that torque commutes up the craft and before the bolts blow its now compromised the craft. The main engines are still in a declining burn  the nose is under Q and the compartment cannot run from the orbiter, its stuck until all thrust go to zero. You can't really modify the orbiters outcome until you deal with the torque issues, and you cant deal with that until you deal with the structural issues on the tank (its liquid oxygen and hydrogen that want nothing more than to bypass the engines and burn). Yes, the orbiter is too close to the tanks, but both are too close to the SRBs that really have a design flaw, the joints. But for the sake of our random argument lets only consider the functions.

The function of an SRB is only to burn, thats it you strike a match and stuff shoots out the back (it applies to all SRB designs). The function of the Red tank was not to burn; it was a fuel supply and so all the forces intrinsic to itself can be prevented. Of course, the orbiter engines can explode, but then there are limitations on the fuel they have access to and thus torque they can produce. There have been several RS-25 failures of these type and none jeopardized the mission. We have to look at the problem logically, we need oxygen and fuel in space, so we can't be so afraid of these things that we never take them. We can have 10 levels of switches on them such they will always be shut off from threat generation.

So all our disintegration thrust vectors are tied to the red tank and attached boosters. There are situations were the red tank could have otherwise failed, there could have been a failing of  a joint it could have suffered Q damage, etc. But then the next step is that the hydrolox would ignite, OK we need at  a spark or lightning, and then on top of that we need some mixing torque to get that 'boom' required to disintigtate the orbiter. So we have an If and If and IF and then construct. Whereas the booster burned a whole through the tank and directly ignited the hydrogen, it circumvented two of the Ifs in  a single step and we dont need and electrical spark. So the probability of the Red tank, in and of itself, triggering the orbiter's fate is much lower than if the booster does it. We can't definitely know how low because we have to cross parameters like when is max Q, when is the most force applied from the boosters . . . . . but needless to say there is a time constraint on when intrinsic forces can occur. And by and large Q is known and F is known and in aircraft these failures are pretty rare (Aloha airlines 737 is the last incident I remember, and the Corsair incident was another set).

This thread really should be about SRBs. WE know about the link of structural failure of the orbiter and random booster malfunction (again we are assuming that this could ever happened inside the rating and that the probability is ~<1/133). OK then what is the correct course. So i have to correct one thing I said, the boosters do produce more thrust, but the main engine produce more thrust * time than the booster produces. As a result the boosters are not the main source of thrust or energy and certainly not the main source of acceleration. Hydrolox has almost twice the Ve of solid fuels.

Therefore boosters are replaceable. And if they are replaceable and are creating excessive risk they should be replaced. But I would argue one other thing, to the  ISP of the boosters is not impressive, we have newer launch systems that have better ISP are more tolerant of single engine failure (since they have nine engines) can be more easily recycled AND can be throttled off in case of an emergency in their operations. So given that why use SRBs on manned missions? The next logic here is that for any system where the booster is close to the orbiter or crew compartment, should we be using solid fuels? So what about mounting SRBS (several way down the red tank, the problem with that if they break the fastening they can slam into the orbiter which is above it and they cannot stop propelling themselves.

So in the model above as drawn and any of its still it does not circumvent the critique because essentially the SRBs can compromise any structure if they are mounted far enough away from the core and dont have active steering functions. Consequently all designs with SRBs are to be considered maybe economical but too risky.

Speaking of risk, we are in shelter in place, again. Last fall we had Harvey, its already snowed once in December and now, apparently, in good ole East Texas, we are having an ice-storm . . Yeah!!! climate change. But to be honest the shelter in place comes from the fact that we down-here lack the ice-driving functions in the brain.

 

 

[sevenperforce]

5 minutes ago, PB666 said:

At least there is one person here thinking about the evolution argument, but in my opinion (n dealing with other posts and getting back to this one at the end) its not about the crew release. Biologically speaking the source of the problem also has to mandate the solution, not the 3rd dependent reaction. As you state the shuttles capabilities are exceptional, just not as efficient as desired.

I say biologically because FIRST the crew has to be in a conscious or mobile state. You can't argue success if three were already unconscious as the moment of force application is completed. So if the state of the system evolves too quickly no crew compartment is going to work thoroughly and if the solution is not going to be complete there is no reason to waste mass to remediate the problem. The problem with the evolution of the STS-51-L is that there was a state that could no longer be contained. Even if one person was conscious there was no way for him to protect the rest of the crew from the effects of decompression, there was no way to alter the shuttles trajectory (other than one-human unit movements) because all of the control features disintegrated. Before we can discuss saving the crew (both in the case of challenger and columbia) we first have to save the orbiter. If the orbiter is significantly torqued to its disintegration point  then its likely you already have dead or nearly dead crew. This is my interpretation of what happened.

Well, I hate to just come right out and disagree, but...I disagree. The orbiter was torqued to disintegration, not by the explosion, but by hitting an off-axis airstream that pushed it beyond its structural limits. The cabin did not disintegrate. The cabin was intact...and, potentially, not even breached...until impact with the Atlantic.

This thread really should be about SRBs. WE know about the link of structural failure of the orbiter and random booster malfunction (again we are assuming that this could ever happened inside the rating and that the probability is ~<1/133). OK then what is the correct course. So i have to correct one thing I said, the boosters do produce more thrust, but the main engine produce more thrust * time than the booster produces. As a result the boosters are not the main source of thrust or energy and certainly not the main source of acceleration. Hydrolox has almost twice the Ve of solid fuels.

Yes. SRBs were bad news. As I said before, if you'd replaced the SRBs with expendable dual-F-1 LFBs of equal size, the Shuttle would have had margins for days.

[PB666]

46 minutes ago, CatastrophicFailure said:

Out of likes already. 

Also @tater, @sevenperforce, et al: The other problem with ejection seats is that if there’s more than four people flying (and there usually were), the rest are down on the middeck, sandwiched between the flightdeck and many metric craptonnes of fuel. There’s simply no way to get them out of all that structure reliably. Making the whole crew module separate and rocket away was possible, maybe, but you’ve got a lot of hoses, lines, and electrical cables that you’ve got to sever all at once, and it’s got to happen right the first time. And the rest of the orbiter needs to be strong enough to not immediately collapse as you’re trying to get away. 

Heres one concept for a crew escape pod in the cargo bay:

@mikegarrison

That model would work if it was pointed with a -radial direction such as it would free itself, but you have two dead crew members on the flight deck. BTW the shuttle was designed, in an emergency to evacuate  11 crew members.

5 minutes ago, sevenperforce said:

ell, I hate to just come right out and disagree, but...I disagree. The orbiter was torqued to disintegration, not by the explosion, but by hitting an off-axis airstream that pushed it beyond its structural limits. The cabin did not disintegrate. The cabin was intact...and, potentially, not even breached...until impact with the Atlantic.

Then don't say it. The cabin apparently depressurized. Since the cabins pressure is through the tail of the craft, if you strip this before the valves close or jeapardize the switches then the cabin vents. SO a depressurization of the cabin is a compromise of the cabin also. More than that, the orbiter was designed to land as it fail-safe option, if that is disable, then the whole can be considered disabled. Again we can except bugs, like the image in the posts above. That considerably alters the function and performance of the orbiter.

Edited January 16, 2018 by PB666

[tater]

While an evolved Shuttle design would have clearly been superior to what we had (incremental improvements on an otherwise frozen design), I disagree with the very idea that Shuttle as built was a suite of capabilities that we needed to be in one vehicle. Until LVs are far, far safer than they have been historically, I think that failure modes involving the LV should be survivable.

There's nothing anyone can do about, say, debris wrecking the heat shield when a craft is in orbit, designs that mitigate against that contingency would become impossibly heavy. A certain level of risk is a default.

Both Shuttle losses were the result of the LV, however. The first due to the SRBs, the second due to the known problems with the ET insulation.

Fixing the latter problem likely increases the dry mass enough that significant payload capacity is lost. STS-1 sustained  damage to ~300 tiles that required replacement due to foam strikes. STS-1. None the less, designed continuously lightened the ET. Wrapping the entire ET in more Aluminum over the foam would clearly have fixed the issue, but at a huge mass penalty. Ditching the foam altogether leads to boiloff issues, but those are clearly superior to a LOC incident. Seems like they should have dumped the foam pretty much immediately after STS-1, given that turn around was greatly slowed already due to dealing with the %@%$#@ tile TPS system.

 

[PB666]

36 minutes ago, tater said:

While an evolved Shuttle design would have clearly been superior to what we had (incremental improvements on an otherwise frozen design), I disagree with the very idea that Shuttle as built was a suite of capabilities that we needed to be in one vehicle. Until LVs are far, far safer than they have been historically, I think that failure modes involving the LV should be survivable.

Yes we can talk about these. But first the shuttle was effectively designed in 1977, 40 years ago, and there is no expectation that in a break-thru industry that a single design should last 40 years. But the RL-10s design is basically the same a expansion cycle cryogenic engine since 1960, that is 57 years. The difference here is that the RL-10 is a component of a system (like an RS232 analog serial connection) and the shuttle is the system. Evolved systems should improve both performance and safety, no doubt and there is plenty of room for replacement. For example pilots could be replaced with flight computers that are controlled via generic commands (like change orbit, or controlled from encrypted ground commands). So get the crew down from 7 to say four. Remove certain functions, get rid of the ISS rescue functions and you have a much smaller crew compartment, more payload, potentially. In hindsite while it seem great that it could carry 7 one has to wonder why it needed to carry many.  LV risk should be low as feasibly possible, launch failures waste time and are diseconomies that must be avoided.

IN terms of risk you can't really say we will tolerate this risk but not that, risk should come down where its the highest and again this is created by the launch. If tiles are popping off in orbit or reentry because some latent factor in shuttle age, its a problem.

36 minutes ago, tater said:

Fixing the latter problem likely increases the dry mass enough that significant payload capacity is lost.

Risk reduction is multifaceted, it does not need to be this or that, it can be this and that and achieve the same result for a lower cost. First cost and risk mitigating issue is if you don't need a multifaceted vehicle and 7 nauts for a mission, why do it. Use a less risky vehicle that takes fewer nauts. Problem solved. But the _and_ remediation issues goes further, why after 30 years do we still need pilots on the missions when dragon clearly shows that certain manned missions are functionally redundant with already available missions. Right there we remove 2/3rds of the human risk. As stated before you don't need nauts to release a Hubble, you can have automated space craft (and actually ion driven level craft can do this much more efficiently) retrieving dead packages and deorbiting them. Even if the ion drive cannot deliver them home it could deliever them to a basket mounted on the ISS where they could potentially be converted to crucial and disposable components, some returned with dragon and others deorbited as waste.

BY the same token (a topic of a different thread) certain functions of the shuttle could have been spaced base. If we can imagine a model were the shuttle builds X and then X₀ builds X₁, X₂, . . .X_N  then ceasing the shuttles function before X was complete economically and temporally unwise. The contractors for the DSG and the cryostation I don't trust to do the job.

36 minutes ago, tater said:

STS-1 sustained  damage to ~300 tiles that required replacement due to foam strikes. STS-1. None the less, designed continuously lightened the ET. Wrapping the entire ET in more Aluminum over the foam would clearly have fixed the issue, but at a huge mass penalty. Ditching the foam altogether leads to boiloff issues, but those are clearly superior to a LOC incident. Seems like they should have dumped the foam pretty much immediately after STS-1, given that turn around was greatly slowed already due to dealing with the %@%$#@ tile TPS system.

Yep, I think if you put a bunch of highschool students in a garage with a snow machine and a mock up of the ET they could probably come up with a solution, Sticky saran wrap on the surface that peeled away in two pieces in the seconds before the launch could have pulled all the little icebergs off the shuttle and the tiles could have been protected. Even better there are things that prevent ice from solifying and remain as a powder. It was a silly problem that NASA and its contractors stumbled over.

Edited January 16, 2018 by PB666

[tater]

10 minutes ago, PB666 said:

If tiles are popping off in orbit or reentry because some latent factor in shuttle age, its a problem.

Tiles were popping off because they were hit by ET foam virtually every, single launch, starting with STS-1.

It was not age, it was a poor design choice.

The problem with any evolving shuttle design as a notion, is that it was simply not going to happen for logistical reasons. Look at EM-1 vs EM-2 for SLS/Orion. The VAB needs to be reconfigured, as well as the launch gantry at a cost of hundreds of millions of $, and 33 months of delay. In the early HTHL Shuttle concept designs, this would be a nonexistent problem. The vehicle could be altered, then you fly it and see if it works better. Sure, there might be an overhead crane system to mount the Orbiter on the stage 1 aircraft, but that can be generic as long as future vehicles are designed within the crane limits. Most Shuttle concepts were in fact VTHL configurations, however, which means that they would suffer the same problem regarding any attempt at design changes that require new integration facilities.

 

[Jaff]

4 hours ago, sevenperforce said:

Realistically, someone probably did think "what if one of these giant tubes of bomb doesn't work", but they were ignored.

From SRB ignition to SRB jettison, there was no abort. ANY malfunction of the SRBs meant LOCV (loss of crew & vehicle). One of the SRBs fails to ignite? The one that DOES ignite melts the pad, rips free, and cartwheels the stack across the landscape, and everyone dies. One of the SRBs has a thrust fluctuation in flight? The stack will start to tailspin and rip itself apart, and everyone dies. An O-ring fails and the side of the SRB burns through? The struts will melt and fail, the SRB will smash into the ET, the orbiter will rip free and disintegrate, and everyone dies.

That's why it was a death trap. Once the SRBs were ignited, you held on and hoped.

What others have said is correct; there was no contingency for dropping the boosters, because dropping the boosters before burnout were instant LOCV. For one thing, the mechanics of separation required that the SRBs burn out while the SSMEs continued to fire; if the separation motors fired while the main motors were still firing, they'd be pushed forward, into the tank. And even if the SRBs could be magically removed, the stack was not aerodynamically stable without them. The thrust vector of the SSMEs went up and through the forward center of the tank; the whole thing was flying off-prograde. The tank would roll and yaw beyond the SSMEs' ability for gimballed correction, the orbiter would rip off, tumble, and disintegrate. Everyone dies.

They couldn't just separate the orbiter from the rest of the stack, either. The attachments of the SRBs were below the centerline of the external tank, to balance the thrust from the main engines. If the orbiter separated, the thrust vector would be under the stack COM and the tank and SRBs would pitch backward, colliding with the orbiter as it separated.

Even if the orbiter could be safely separated from the stack, it was not passively aerodynamically stable at any point in the ascent. It was built for entry, gliding decent, and unpowered landing; it was in a stalled state through the entire ascent and was carried only by its engines and the SRBs. In the Challenger failure, the orbiter likely did not take significant collision damage from the SRBs or the ET; rather, the orbiter simply ripped itself apart in the off-axis airstream.

Yep. The Shuttle looks big and tough, like some super-hardy ginormous fighter jet, but in reality it was far more fragile than an airliner of comparable size. It had the glide ratio of a brick and the structural integrity of a kite.

Of course, this is because it was super cutting-edge. There is no way we should have been able to make a VTHL crew-and-cargo spaceplane with reusable engines back then. Every single part had to be custom-made, every single part had to be constructed from the most lightweight materials, and every single part had to work perfectly.

Thanks for the really informative (if not seemingly heavily biased) reply, it is really interesting.

 

 

[DAL59]

On 1/14/2018 at 10:29 PM, sevenperforce said:

Which design was the HOTOL one?

While we're on the subject of alternate Shuttles, might I submit what has got to be THE most inaccurate scene from anything involving the Shuttles, ever:

Like...what the actual hell?

Are they supposed to be...underwater?

http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsAnOcean

[PakledHostage]

There's a lot of misinformation swirling around in here that suggests that several people haven't read the Rogers Commission Report. I suggest that those who haven't read it please do so before spouting on about the causes of the Challenger accident and the accident sequence.

[PB666]

1 minute ago, tater said:

Tiles were popping off because they were hit by ET foam virtually every, single launch, starting with STS-1.

It was not age, it was a poor design choice.

The problem with any evolving shuttle design as a notion, is that it was simply not going to happen for logistical reasons. Look at EM-1 vs EM-2 for SLS/Orion. The VAB needs to be reconfigured, as well as the launch gantry at a cost of hundreds of millions of $, and 33 months of delay. In the early HTHL Shuttle concept designs, this would be a nonexistent problem. The vehicle could be altered, then you fly it and see if it works better. Sure, there might be an overhead crane system to mount the Orbiter on the stage 1 aircraft, but that can be generic as long as future vehicles are designed within the crane limits. Most Shuttle concepts were in fact VTHL configurations, however, which means that they would suffer the same problem regarding any attempt at design changes that require new integration facilities.

 

Yeah but thats trivial, sorry, but after 133 flights and 30 years the VAB should have been booked (depreciated) and funds allocated for a newer VAB. I have no problem with replacement crewed repair and build facilities, but the way I look at it those designs are about 20 years too late. You can't complain, NASA works like the US military at times, they should have had a better head for business and again if you had soldiers in the field dealing with falling ice, you could almost bet that mothers and sisters back home would be screaming at their congressmen to hire a contractor that will fix the problem, thats what happened with the humvie and after about 7 years they had a replacement. The relationship between contractor and contractee is too cozy. You have a problem like that and you take bids from others that commit to fix the problem . . .Were we married to the big orange tank? This of course doomed the shuttle.

 

[HebaruSan]

5 minutes ago, PakledHostage said:

There's a lot of misinformation swirling around in here that suggests that several people haven't read the Rogers Commission Report. I suggest that those who haven't read it please do so before spouting on about the causes of the Challenger accident and the accident sequence.

What specifically was the misinformation, and what is the correction? Just linking the report isn't going to un-do any misperceptions that may have been caused in the casual reader who isn't going to take time off to read 250+ pages.

[PakledHostage]

2 minutes ago, HebaruSan said:

What specifically was the misinformation, and what is the correction? 

I don't have time to summarize the whole report and it is better to go directly to the source anyway. You don't need to read the whole thing.  Chapters III and IV are a good start.

[HebaruSan]

1 minute ago, PakledHostage said:

I don't have time to summarize the whole report and it is better to go directly to the source anyway. You don't need to read the whole thing.  Chapters III and IV are a good start.

You don't need to summarize the whole report to quote the "misinformation swirling around here".

[tater]

4 minutes ago, PakledHostage said:

I don't have time to summarize the whole report and it is better to go directly to the source anyway. You don't need to read the whole thing.  Chapters III and IV are a good start.

Regardless, had the side boosters been the liquid ones that were competing with the SRBs (that lost), there might have been another LOC incident, but it would not have been what happened to Challenger.

The ET weight reductions over the years were pretty significant, BTW, not just the 300kg of white paint, but in fact several tons of slimming. Perhaps combined with a skin they might have prevented Columbia's accident while mitigating some of the mass penalties.

Edited January 16, 2018 by tater

[sevenperforce]

Not sure what he's angling at, either, but this is a good start to correct some common misconceptions:

Spoiler

All fractures and material failures examined on the Orbiter, with the exception of the main engines, were the result of overload forces, and they exhibited no evidence of internal burn damage or exposure to explosive forces. This indicated that the destruction of the Orbiter occurred predominantly from aerodynamic and inertial forces that exceeded design limits. There was evidence that during the breakup sequence, the right Solid Rocket Booster struck the outboard end of the Orbiter's right wing and right outboard elevon.

...

The crew module wreckage was found submerged in about 90 feet of ocean water concentrated in an area of about 20 feet by 80 feet. Portions of the forward fuselage outer shell structure were found among the pieces of crew module recovered.20 There was no evidence of an internal explosion, heat or fire damage on the forward fuselage/crew module pieces. The crew module was disintegrated, with the heaviest fragmentation and crash damage on the left side. The fractures examined were typical of overload breaks and appeared to be the result of high forces generated by impact with the surface of the water.

 

6 minutes ago, tater said:

Regardless, had the side boosters been the liquid ones that were competing with the SRBs (that lost), there might have been another LOC incident, but it would not have been what happened to Challenger.

The ET weight reductions over the years were pretty significant, BTW, not just the 300kg of white paint, but in fact several tons of slimming. Perhaps combined with a skin they might have prevented Columbia's accident.

Liquid boosters can, at least, be throttled.

One concern with adding a skin to prevent another Columbia was that then the skin could freeze, peel, and come off in even larger and more dangerous chunks. Liquid hydrogen is cold stuff.

Edited January 16, 2018 by sevenperforce

[PB666]

13 minutes ago, sevenperforce said:

Not sure what he's angling at, either, but this is a good start to correct some common misconceptions:

  Reveal hidden contents

All fractures and material failures examined on the Orbiter, with the exception of the main engines, were the result of overload forces, and they exhibited no evidence of internal burn damage or exposure to explosive forces. This indicated that the destruction of the Orbiter occurred predominantly from aerodynamic and inertial forces that exceeded design limits. There was evidence that during the breakup sequence, the right Solid Rocket Booster struck the outboard end of the Orbiter's right wing and right outboard elevon.

...

The crew module wreckage was found submerged in about 90 feet of ocean water concentrated in an area of about 20 feet by 80 feet. Portions of the forward fuselage outer shell structure were found among the pieces of crew module recovered.20 There was no evidence of an internal explosion, heat or fire damage on the forward fuselage/crew module pieces. The crew module was disintegrated, with the heaviest fragmentation and crash damage on the left side. The fractures examined were typical of overload breaks and appeared to be the result of high forces generated by impact with the surface of the water.

 

Liquid boosters can, at least, be throttled.

One concern with adding a skin to prevent another Columbia was that then the skin could freeze, peel, and come off in even larger and more dangerous chunks. Liquid hydrogen is cold stuff.

Heat it up before you expel it, more modern towers have improved heavy gas removal systems. 

The reports conclusion was that the primary orbiter damage was cause by an Srb hitting and separating the right wing. But at the same time the orbiter was enveloped in a shroud of RCS which means that the RCS was also involved, this obviousl was liberated by the impact.  They don't believe that the red tank was involved in the disintegration because by the time the h2 had ignited it appears that the upper orbiter had separated. 

I doesn't really change the conclusion, but again if the SRB can hit the right wing it can also hit the crew escape module, having the SRBs able to range vectors in the direction of the orbiter is a bad thing made worse by a no-abort mode on the SRB.

The true fail safe would have been to kill the orbiters engine and break from ET  and pray, still I don't think it would have translocated horizontally fast enough to prevent wing damage, but maybe preserve RCS burn and that would have been something. The diagnosis showed that the crew hatch worked but was never opened, no one tried to escape, you might have better luck hitting the water at terminal velocity than in an orbiter at terminal velocity, particularly if you could use your uniform to slow down.

The final conclusion does not remark upon anything but the Right SRB.

 

 

[tater]

41 minutes ago, sevenperforce said:

Liquid boosters can, at least, be throttled.

One concern with adding a skin to prevent another Columbia was that then the skin could freeze, peel, and come off in even larger and more dangerous chunks. Liquid hydrogen is cold stuff.

I mean an aluminum skin, not some sprayed on membrane. Tanks, insulation, external metal skin. Again, the mass penalty would be HUGE, it's effectively a double tank. This presumes of course that you don't just axe the foam altogether, and compensate for the boiloff another way (or lose some dv, and lower the payload to orbit as a result).

[sevenperforce]

21 minutes ago, PB666 said:

The reports conclusion was that the primary orbiter damage was cause by an Srb hitting and separating the right wing. But at the same time the orbiter was enveloped in a shroud of RCS which means that the RCS was also involved, this obviousl was liberated by the impact.  They don't believe that the red tank was involved in the disintegration because by the time the h2 had ignited it appears that the upper orbiter had separated. 

Err, no.

"The destruction of the Orbiter occurred predominantly from aerodynamic and inertial forces that exceeded design limits."

The RCS system ignition took place after the aerodynamic load caused structural failure in the orbiter which breached those tanks; it was not involved. No portion of the cabin showed damage from combustion products, flame, or debris; it merely ripped apart in the airstream.

Virtually the entire cabin was recovered, and there was no positive indication that the cabin was breached prior to impact with the Atlantic. Depressurization or breach would have made it unlikely for the crew to take any action; the attempted activation of emergency oxygen was more likely the result of the impending vehicle destruction than a response to a depressurization event. If I was in the Shuttle and experienced it coming apart around me, I sure as hell wouldn't wait for the cabin to depressurize before grabbing for oxygen.

[PB666]

9 minutes ago, sevenperforce said:

Err, no.

"The destruction of the Orbiter occurred predominantly from aerodynamic and inertial forces that exceeded design limits."

The RCS system ignition took place after the aerodynamic load caused structural failure in the orbiter which breached those tanks; it was not involved. No portion of the cabin showed damage from combustion products, flame, or debris; it merely ripped apart in the airstream.

Virtually the entire cabin was recovered, and there was no positive indication that the cabin was breached prior to impact with the Atlantic. Depressurization or breach would have made it unlikely for the crew to take any action; the attempted activation of emergency oxygen was more likely the result of the impending vehicle destruction than a response to a depressurization event. If I was in the Shuttle and experienced it coming apart around me, I sure as hell wouldn't wait for the cabin to depressurize before grabbing for oxygen.

Err the inertial forces initiated when the booster hit the wing and a bunch of liberated RCS blew de f up. Breach meant they had 15 seconds to take action after which no air to breath no escape from hatch no open hatch, the hatch worked nominally. Whatever the case, the SRB caused the accident, not the orbiter or the red tank. The report  clearly blames the SRB and blames nothing else. The reports states specifically that the SRB hit the wing and glanced off the core. The absolve the ET in all cause of the force generation as it occurred after RCS ignited. Therefore the source of the inertial was the SRB and the source of the aerodynamic shift again was the SRB and RCS.

I repeat again if you had a crew escape, there is nothing to prevent the SRB from hitting that section of the orbiter.

Edited January 16, 2018 by PB666