STS Shuttle discussion thread

[tater]

11 minutes ago, PakledHostage said:

As an engineer yourself, you know that is a ridiculous assertion... The shuttle isn't a car. It is as high performance a vehicle as ever existed. It is being imparted with literally megajoules of energy per kilogram during launch. It has to operate on razor thin margins or it wouldn't fly. Sure it is far from perfect and 20:20 hindsight has shown that there were areas that could have been improved from the outset. But compromises had to be made during its development and the people making those decisions probably:

a) weren’t dimwits
b) were privy to information that a bunch of armchair engineers on the internet aren’t considering in their criticisms

The people making those decisions back in the ‘70s also certainly didn’t have the benefit of hindsight that we all have today.

The problem is that their design constraints were not always engineering.

SRBs were chosen because of politics, not engineering.

There were suggestions for alternate TPS schemes*, but tiles were seen as less expensive, and possible to fix piecemeal if any were compromised (not realizing operationally how many would be lost, and the vast work it was to go over literally every tile and seam every flight).

Shuttle was a great "X vehicle" as was said up the thread. Lessons learned could have been folded into an entirely new design, taking those lessons into consideration. That's not how the sausage gets made, however. It was either cancel the whole program, or stick with what they had, so they did the latter. Incremental changes improved each Orbiter, to be sure, but it was wed to the initial design in a way that is pretty hard to deal with---it has to mate the same way, in the same geometry, or the whole program falls apart (has to share facilities, etc).

*they looked at active cooling as I recall.

Edited January 17, 2018 by tater

[mikegarrison]

3 minutes ago, tater said:

The problem is that their design constraints were not always engineering.

Engineering design constraints are never "always engineering". No interesting engineering project ever didn't have to worry about budget, schedule, supplier reliability, customer interest, public opinion, etc. etc.

[GoSlash27]

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

Edited January 17, 2018 by GoSlash27

[tater]

13 minutes ago, mikegarrison said:

Engineering design constraints are never "always engineering". No interesting engineering project ever didn't have to worry about budget, schedule, supplier reliability, customer interest, public opinion, etc. etc.

Very true.

It's worse in the situation where the vehicle is intentionally going to be made by literally as many contractors as possible, however, and the design from above just internalizes that.

With the ability to really iterate, maybe they could have fixed it. They noticed the foam damage on literally the first flight though. They worked to improve foam application techniques to avoid large chunks, but ditching the foam was never on the table as far as I could ever tell.

7 minutes ago, GoSlash27 said:

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.

That might be a viable vehicle, but it's not a shuttle. Reuse was kind of the point.

Have any of you guys read Phil Bono's book, Frontiers of Space? It's from 1969, and he does the math that SpaceX and BO are doing now. He flatly states there is no way to get cost to orbit lower without reuse, and with reuse, it can drop precipitously. Shuttle was supposed to do that. The VTHL designs (most were like Shuttle in this respect), and the VTVL designs (Bono's own work) were all reusable. A couple were HTHL designs as well. I think all the engineers were on the same page regarding reuse. Look at the concept art for prepping Shuttle, LOL. Nothing at all like months of fine tooth comb work on tile seams.

Edited January 17, 2018 by tater

[GoSlash27]

5 minutes ago, tater said:

That might be a viable vehicle, but it's not a shuttle. Reuse was kind of the point.

'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]

Out of reactions for the day.

That goes back to the X nature of shuttle. With that as the mindset, I think it could have evolved. It’s like SLS though. They can decide to use it for the moon (surface/LLO), but they’ll come up with some work-around since The system can’t get there, instead of just making a better SLS, since that can’t happen.

[PakledHostage]

1 hour ago, mikegarrison said:

Engineering design constraints are never "always engineering". No interesting engineering project ever didn't have to worry about budget, schedule, supplier reliability, customer interest, public opinion, etc. etc.

Exactly. And in my former life, my own Pakleds were always pushing me to cut margins to "make it go", because being too conservative costs money. But a disaster resulting from stretching things too far is even more expensive so you've got to find a balance. History (and the Rogers Commission Report) finds that the Pakleds in charge of the Challenger launch decision pushed things too far, despite the protests of their engineering "hostages" that the launch would be conducted outside the razor thin limits that were necessary for Shuttle to be a practical, real-world entity.

Edited January 17, 2018 by PakledHostage

[GoSlash27]

5 minutes ago, PakledHostage said:

Exactly. And in my former life, my own Pakleds were always pushing me to cut margins to "make it go", because being too conservative costs money. But a disaster resulting from stretching things too far is even more expensive so you've got to find a balance. History (and the Rogers Commission Report) finds that the Pakleds in charge of the Challenger launch decision pushed things too far, despite the protests of their engineering "hostages" that the launch would be conducted outside the razor thin limits that were necessary for Shuttle to be a practical, real-world entity.

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.

[Starman4308]

1 hour ago, PakledHostage said:

As an engineer yourself, you know that is a ridiculous assertion... The shuttle isn't a car. It is as high performance a vehicle as ever existed. It is being imparted with literally megajoules of energy per kilogram during launch. It has to operate on razor thin margins or it wouldn't fly. Sure it is far from perfect and 20:20 hindsight has shown that there were areas that could have been improved from the outset. But compromises had to be made during its development and the people making those decisions probably:

a) weren’t dimwits
b) were privy to information that a bunch of armchair engineers on the internet aren’t considering in their criticisms

The people making those decisions back in the ‘70s also certainly didn’t have the benefit of hindsight that we all have today.

I would argue that the whole project was conducted under a level of political pressure and optimism that led to failures at every level, from the initial design work all the way to the actual flights.

For example, while the proximal cause for the Challenger disaster was a management issue of ignoring the engineers, the proximal cause is just one element of the disaster.

If I may make a brief analogy, some blame the loss of the Japanese aircraft carriers at Midway to a single scout plane's failure, but why that allowed all 4 carriers to go up in flames takes an entire book to describe.

 

A brick of statements below:

Spoiler

 

The SRBs failed because the cold weather caused a joint to fail.

The Shuttle was allowed to launch because the program manager ignored the engineers, due to the mission already being tardy.

The reason why there was so much launch pressure was because the manned Shuttle program had been subordinated to launching commsats, and people were getting impatient with delays in the STS program.

The reason it had been subordinated to launching communication satellites was because it had been promoted as a space truck.

The reason the Shuttle didn't actually function as a space truck was because so many requirements had been added that the Shuttle had to be one of the largest and most complicated launch systems ever.

The reason the astronauts were unable to survive a launch vehicle malfunction was because there was no functional LAS.

There was no functional LAS because the manned segment was placed on the side of the fuel tank.

The manned segment had been placed on the side of the fuel tank because that's the only way they could satisfy all the numerous mission requirements.

 

 

Overall, the Shuttle was dangerous and expensive, and for the huge sums of money invested into it, we could've had a much more impressive manned space program than we did. There was no reason to haul up life support and a mini space station every time they wanted a communications satellite in orbit: put that on an ordinary cargo rocket, get it up for a fraction of the price, and redirect the savings to put up a permanent space station in orbit.

That astronaut killer sucked up far too much money over its lifetime, decades of potential progress dedicated to an overly politicized X-plane that had been promoted as a reliable space truck, despite relying on a swathe of unproven technologies.

Cargo and crew should, from here on out, be strictly separated. All the scientific equipment and extended life support capacities of the Shuttle could have been more cheaply sent up on a separate rocket, to which a conventional capsule could have docked.

[sevenperforce]

Speculative question: if the SRBs would have been given emergency blowout charges, to vent pressure and cut thrust (without a full FTS activation) in the event of an unrecoverable SRB problem, would it have even potentially helped Challenger?

If the range safety officer had seen the right SRB's thrust dropping and gimbal correction exceeding recoverable limits, and pushed the button to blow out the pressure before the bearing strut failed, would that stack have maintained aerodynamic stability long enough for the orbiter to cut its engines and pull away gracefully?

Seems unlikely, but at least it would have been a chance.

[PB666]

3 hours ago, GoSlash27 said:

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.

If the crew had been hit by a separated booster then they all died, anyway and it also means you did not read the report, the SRB hit the orbiter, large inertial forces ensued and aerodynamic stress quickly followed. The crew capsule is not made of fairy dust, it has weight and structural limits.

[sevenperforce]

4 minutes ago, PB666 said:

If the crew had been hit by a separated booster then they all died, anyway and it also means you did not read the report, the SRB hit the orbiter, large inertial forces ensued and aerodynamic stress quickly followed. The crew capsule is not made of fairy dust, it has weight and structural limits.

Le sigh.

The SRB clipped the orbiter wing. It dented the wing. Inertial and aerodynamic forces ripped the orbiter apart because it started tumbling, not because of impact damage.

And all this misses @GoSlash27's point: if the crew is in on top of the rocket, a misbehaving SRB cannot hit them in the first place.

[PB666]

2 hours ago, tater said:

Right after the destruction of Columbia, the Shuttle Program manager was saying that it could not have been a foam strike. Even then they would not believe that foam could damage the vehicle enough for a LOC incident.

They saw the foam as a problem, but not a danger all those years.

In retrospect, you have to wonder about their tile loss statistics, and the presumed cause. At the time (1990s and earlier), you'd hear that the acoustics of launch shook tiles loose, and they lost something like quite a few tiles per launch. But this was an assumption partially based on not thinking that expanding foam could really do much damage on impact. How many of those acoustically lost tiles were actually the result of foam strikes? We'll never know.

That's because they were separating two things, foam and ice, when Ice gets in the foam it becomes rigid and gains inertia, and so it is susceptible to added stress, and when the foam breaks it has more inertia, its travel is less directed by air, it can travel horizontally farther. The ice was a problem and the foam is a problem and the two combined is a big problem.

Quote

The shuttle's utility as a vehicle was certainly lowered after Columbia. If you really wanted to be safe, send crew to ISS on shuttle, and inspect shuttle for damage. If crippled, stay at ISS. Shuttle was an expensive way to get to ISS, though.

Strapped to a bomb doesn't even matter, except right after launch. Once the thing was really moving, most any separation from the stack would result in a RUD of the Orbiter.

After the ISS the crew support function was redundant with other functions, and if your payload bay was not full, it was a waste, better to use a supply vehicle.
 

1 hour ago, GoSlash27 said:

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.

WOuld you get off of this, it had 133 successful flights, some things were done right, again the engineering discussion is about the critical flaws, not "i feel like it was a flaw and therefore it was a flaw".

[PB666]

6 minutes ago, sevenperforce said:

Le sigh.

The SRB clipped the orbiter wing. It dented the wing. Inertial and aerodynamic forces ripped the orbiter apart because it started tumbling, not because of impact damage.

And all this misses @GoSlash27's point: if the crew is in on top of the rocket, a misbehaving SRB cannot hit them in the first place.

Hiting the wing is an inertial force, when it hit the top of the tank, according to the report, it tore open the top of the tank and sent oxygen into the hydrogen, when it hit the orbiter it factored into the disintegration. The time it took between hitting the tank and hitting the orbiter was on the order of milliseconds, read the report.
 

READ the whole report, not just the part you like.

 

 

dense.

[CatastrophicFailure]

2 hours ago, tater said:

Out of reactions for the day.

I most definitely concur. 

 

1 hour ago, PakledHostage said:

Exactly. And in my former life, my own Pakleds were always pushing me to cut margins to "make it go"

Heh. All this time I was reading it as PickledHostage. 

 

I swear, this thread must have set some kinda forum growth record...

[PB666]

48 minutes ago, sevenperforce said:

Le sigh.

The SRB clipped the orbiter wing. It dented the wing. Inertial and aerodynamic forces ripped the orbiter apart because it started tumbling, not because of impact damage.

And all this misses @GoSlash27's point: if the crew is in on top of the rocket, a misbehaving SRB cannot hit them in the first place.

And that is bull _____. The 12 strut failed (dont talk here if you are not going to read the report), it means that now the booster is lost half of its breaking force and almost all of its resistence to torque. Coming close to  the end of the burn, the force delivered to the ET was approaching maximum and it tore into the tank and hit the orbiter, thats only one solution, it could have just broken free and hit anything in its pass, it could have broken free and at the same time ignited the top of the booster deflecting off the ET, and hit something 50 feet above the orbiter The report basically says this at the beginning, there are somethings we can answer by examining the ground state an sensors other with the analysis of the materials, but there are many questions that cannot be answered to satisfaction do to the lack of index reporting. And again, had the hole been a little bit another direction and caused a rip in the ET along the joints, the forward strut might have also given.  , its a tempest.

THe report basically says this, we looked at everything we could look at, from the orbiters components and child components, to the tank to the engines, no fault could be found in any of the systems other than the damage that the SRB caused, its seems political, but tracing the burn marks on the wings, the tiles on the core, timing of gas releases, . . . . .the tempest was moving very rapidly from one state to the next within essentially 1 second the 12 broke it forced the ET into the orbiter it slammed into the tank and then hit the orbiter and at that point everything disintegrated.

 

Edited January 17, 2018 by PB666

[CatastrophicFailure]

45 minutes ago, sevenperforce said:

If the range safety officer had seen the right SRB's thrust dropping and gimbal correction exceeding recoverable limits, and pushed the button to blow out the pressure before the bearing strut failed, would that stack have maintained aerodynamic stability long enough for the orbiter to cut its engines and pull away gracefully?

I think not. The entire reason for the ridiculous RTLS “keep going the wrong way then turn around to burn off fuel” maneuver is because it’s impossible to separate safety from a full or nearly full ET. There’s no seperatrons, the shuttle used its RCS, so even in an RTLS abort, to get away from the tank with any hope of safety the stack had to be in space and the tank around 2% full. 

The shuttle could theoretically keep going on SRB’s with all three main engines out after a point, but it was comsidered a guaranteed LOCV because of the tank issue after SRB burnout. Check out the Wikipedia page on shuttle abort modes for lots of good info... and exactly how deadly they all were, especially before Challenger.  

[PB666]

1 hour ago, sevenperforce said:

If the range safety officer had seen the right SRB's thrust dropping and gimbal correction exceeding recoverable limits, and pushed the button to blow out the pressure before the bearing strut failed, would that stack have maintained aerodynamic stability long enough for the orbiter to cut its engines and pull away gracefully?

The only viable solutions would have been to kill main engine and release the main tank allowing the booster to carry the ET away.

Edited January 17, 2018 by PB666

[RCgothic]

Yes, the SRBs could tear free and overtake the stack, LOCV even for a capsule. SRBs have no business on a manned rocket. LFBs could be throttled down to prevent this. SLS is not free from this failure mode.

The other failure mode is being on the side of the stack in the path of falling debris. The orbiter was on the side of the stack to enable recovery and reuse of the main engines in a gliding recovery. That wasn't as cheap and effective as advertised, and procluded abort modes for substantial portions of the flight. The exposure of the orbiter to these risks was in hindsight entirely pointless, and it should have been with foresight following STS-1 if not sooner.

Manned vehicles must have abort modes from 0-0.

Edited January 17, 2018 by RCgothic

[purpleivan]

4 hours ago, PB666 said:

If the crew had been hit by a separated booster then they all died, anyway and it also means you did not read the report, the SRB hit the orbiter, large inertial forces ensued and aerodynamic stress quickly followed. The crew capsule is not made of fairy dust, it has weight and structural limits.

However the booster didn't detach completely, only the aft field joint was affected by the burning propellant from the leaking seal. The booster pivoted into the ET, which would likely not have resulted in the loss of the orbiter at that stage in the launch, had it been on top of the stack.

Caveat IANARS.

[RCgothic]

But it could have torn free completely, at which point it overtakes the stack and even a capsule with a rapid abort response is at risk.

Liquid boosters can be throttled down. 

SRBs have no place on a manned launch.

[GoSlash27]

8 hours ago, PB666 said:

WOuld you get off of this,

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.

Edited January 17, 2018 by GoSlash27

[GoSlash27]

2 hours ago, RCgothic said:

But it could have torn free completely, at which point it overtakes the stack and even a capsule with a rapid abort response is at risk.

 I understand that this isn't your point, but it is far less likely for that to happen than having the booster impact the orbiter right next to it. A capsule is also a lot more resilient than an orbiter.

2 hours ago, RCgothic said:

Liquid boosters can be throttled down. 

SRBs have no place on a manned launch.

SRBs can be equipped with thrust termination ports like they use on ICBMs. It is possible to shut them down instantly in the event of an abort, so I wouldn't say they should never be used on a manned launch.

Liquid fuel boosters are safer overall, tho'.

Best,
-Slashy

[RCgothic]

Fair points both. Capsule and Liquid boosters is still safest though.

[PB666]

3 hours ago, GoSlash27 said:

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.

Really, your judgement is not clouded, 134 successful launches, 1 launch failure judged to be a management issue, one reentry disintegration. 100s of successful astronauts placed into space
Dozens of complete science mission, built the ISS, the most productive science platform in the history of mankind (and including a platform repair 2 upgrades and life extension). The most capable launch vehicle ever built (7 people into space, up to 11 back from space, 4.8 x 18 meter cargo bay, 27,000 kg to LEO, a science laboratory, an observatory, capable of launching multiple satellites at once, capable of repairing satellites - including returns science satellites, capable of recycling itself and the satellites that it captures).

If you have for comparison something that has better performance than ^^^^^^ then you might have credibility on whose judgement is clouded, and it you don't . . . . . . .

I live in the world that exists, not in some fantasy world where you can pretend that something better exists and then compare that with reality and opining about realities flaws.

Lets see what happened in the wake of the shuttle . . . . .

NASA has no manned launch system, the manned launch system that is under contract is rampant with cost overruns, has not anywhere near being tested, it only useful a limited number of manned operations, its incredibly expensive, to be launched on the most expensive launch system that exist, alot of QC issues in that system.

Meanwhile, no in space repair capability (except ISS and almost nothing is in its elliptical). No ability to assemble platforms in space, no ability to do manned science missions outside of the ISS.

And also 7 years after the fact no gateways, no manned missions to celestials, no replacement of shuttle with more evolved systems, just vaporware.

With all its various flaws and weaknesses at its core the shuttle could do things no other platform could do, and it made other tasks (like assembly in space) easier.

What has happened is the most capable launch system ever built has been replaced with vaporware, because management could not be made to resolve problems, avoid risk and insist on evolution.

Thats what it is,  the reports conclusion was management issue, the foam/ice issue was a management issue, the SRB issue was a political issue. Its amazing that the shuttle did not have more incidences, but the facts speak to its accomplishments.

 

 

Edited January 17, 2018 by PB666