Why didn't NASA replaced the SRB of challenger?

[goldenpeach]

The leak on the SRB was noticed long ago, why didn't the NASA replaced it?

Does the engineers underestimated the risk?

Does the fault goes to the administration?

Thank you for reading this (short) thread!

[Kerbin Dallas Multipass]

A delay of the launch would have probably done the trick.

Yes they obviously underestimated the risk of cold O-rings.

I guess several departments can be blamed. Nobody acted recklessly but the whole shuttle program was daring. Expectations were however that it had to work like a commuter bus.

[Starwaster]

A delay of the launch would have probably done the trick.

Yes they obviously underestimated the risk of cold O-rings.

I guess several departments can be blamed. Nobody acted recklessly but the whole shuttle program was daring. Expectations were however that it had to work like a commuter bus.

Unfortunately NASA has a history of this sort of thing. Not only has it cost us unmanned probes but Challenger wasn't even the first avoidable loss of life.

Apollo 1 for example was totally avoidable. Several people, most notably the three astronauts themselves, voiced concerns about numerous facets of the capsule design and that suits they wore, which had flammable components. Changes were promised but were never made.

On the unmanned side, that probe that we lost due to the metric / imperial measurement debacle could have been saved even after the erroneous maneuver burn was made. Someone noticed that the craft was not on course and meetings were held and the cause was made known. A standard course correction (contingency plans made far in advance) was agreed upon.... and then it was never made.

I don't mean to rip on our space program but some of the worst disasters we've had were all avoidable. It's not so much that risks were underestimated (that would be forgivable) so much as they were played down by those responsible for decision-making

[aeronaut]

There was a book written about this called Truth Lies and O-Rings. I haven't gotten around to reading it yet but we did do a short case study on this in one of my classes. There were a few engineers at Morton Thiokol who expressed concerns about the O-rings being too cold and therefore not sealing properly. This issue was brought up to NASA however at the end of the day Morton Thiokol and NASA decided not to further investigate the issue and to proceed with the launch.

The leaking O-ring was not a known issue before this event, the concern stemmed from the fact that the O-rings properties had not been characterized at the low temperatures that were seen the night before launch. The temperature overnight (18 degrees Fahrenheit) was outside the range of temperatures that the O-rings had been tested. It turns out at these low temperatures the O-rings become brittle and crack, this is what caused the leak and eventual failure of the SRB.

Blame can be put in a lot of places, when it comes down to it NASA and their contractors had become complacent due to a string of successful launches which caused this concern to be downplayed and ignored. It's sad but sometimes it takes an accident like this to provide a wake up moment to realize that this is space flight and even though it may seem routine the danger is still very real.

[Kerbin Dallas Multipass]

@Starwaster

NASA can be blamed. Absolutely true without a doubt. Not helpful though.

[DaveofDefeat]

Everything looks obvious in hindsight. One concern out of thousands of concerns that occurs.

The only problem is only one thing needs to go wrong.

[rpayne88]

Challenger was a victim of the psychological principle of groupthink. Everyone managing the flight was rushing to get it into orbit rather than wait for better conditions and check the entire system. Groupthink made them ignore the risk.

Edited October 11, 2013 by rpayne88

[Kerbart]

Everything looks obvious in hindsight. One concern out of thousands of concerns that occurs.

The only problem is only one thing needs to go wrong.

The problem is that an issue like this occurs. A committee is formed, the root cause is analyzed and the problem is “fixed.â€Â

If you don’t see what’s fundamentally wrong with what’s described above you’re part of the problem... NASA addresses issues. What they’re not addressing is their culture. Until that changes things like these will continue to happen.

[3_bit]

There was a video about this. The weather was too cold for the SRB, and the double o-rings failed as a result of the cold weather. The SRBs were actually never designed to withstand it, and I believe some person at NASA overrode the manufacturer's recommendation to delay the launch. Long story short, they voided the warranty by flying them under poor conditions. However, the fact they survived liftoff--when pressure is at it's highest-- means that they were pretty resilient.

[sojourner]

Discovery channel has a dramatization coming soon of the events. Saw a commercial for it the other day.

[WestAir]

The problem is that an issue like this occurs. A committee is formed, the root cause is analyzed and the problem is “fixed.â€Â

If you don’t see what’s fundamentally wrong with what’s described above you’re part of the problem... NASA addresses issues. What they’re not addressing is their culture. Until that changes things like these will continue to happen.

This.

The same approach is done in almost every massive industry. In the Global Security field we respond to threats after they're made apparent, not before. [For instance, it took an airline employee taking a gun through security and shooting his boss and three pilots, causing a crash, for us to change the rules requiring flight crew to be screened] In aviation it took two planes colliding over the Grand Canyon for us to decide we needed air traffic control. In the building regulatory industry it took a boss locking hundreds of factory workers into a Manhattan structure with no fire exit, resulting in a fire that slaughtered way too many people, for us to require fire doors and escape routes be made mandatory.

We as a society seem content to respond to disasters, rather than prevent them. It's as if the people in charge look at the statistics of a plausible disaster and say "We have a 12.5% chance of a catastrophic disaster? Not worth the money to prevent."

A trend I've noticed over the centuries is that the people who make such decisions are never the ones killed by them.

[Starwaster]

There was a video about this. The weather was too cold for the SRB, and the double o-rings failed as a result of the cold weather. The SRBs were actually never designed to withstand it, and I believe some person at NASA overrode the manufacturer's recommendation to delay the launch. Long story short, they voided the warranty by flying them under poor conditions. However, the fact they survived liftoff--when pressure is at it's highest-- means that they were pretty resilient.

actually the o-ring that failed did fail at launch. the gap was plugged by the fuel itself until a minute into the launch when it burned away or was just dislodged.

[Piwa]

The leak on the SRB was noticed long ago, why didn't the NASA replaced it?

Does the engineers underestimated the risk?

Does the fault goes to the administration?

Thank you for reading this (short) thread!

It makes no sense here, it would be better to create a common theme of errors for which the death occurred in the space, not just the space shuttle. Now the answer to this question, because human beings are fallible.

[Nibb31]

The leak on the SRB was noticed long ago, why didn't the NASA replaced it?

Does the engineers underestimated the risk?

Does the fault goes to the administration?

That's not what happened. There was no leak or other defect on the SRB. The parts were compliant with NASA's specification requirements. The problem was that NASA was working outside of the limits of the specification.

http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster

The O-rings (the gasket that fits between the steel casing segments of the SRB) were certified for a specific operation temperature range. Notably, they should not be exposed to temperatures below 4°C. The pre-launch conditions were colder than usual, and the temperature during the night went below -8°C. NASA knew that it was operating outside of the temperature range limits, but the Shuttle program was under a lot of pressure, the launch rates were high, and everyone was a bit too confident. As a result, NASA underestimated the risk and decided to launch anyway.

If you go through History, there is not a single transportation accident that isn't avoidable. The problem is anticipating everything that could go wrong... and when spaceflight is involved, there is a lot that can go wrong. It's hard to anticipate all the failure modes.

Edited October 11, 2013 by Nibb31

[jwenting]

The problem is that an issue like this occurs. A committee is formed, the root cause is analyzed and the problem is “fixed.â€Â

If you don’t see what’s fundamentally wrong with what’s described above you’re part of the problem... NASA addresses issues. What they’re not addressing is their culture. Until that changes things like these will continue to happen.

and you're delusional if you think the purpose of those committees is to fix the actual problem. Their purpose is to prevent lawsuits, prevent bureaucrats from taking the blame for their errors and mistakes, instead laying blame on preferably the dead and if that's not possible someone, anyone, outside the organisation.

So the Challenger explosion was blamed on the design of the O rings, rather than on the decision of someone in a heated office somewhere in NASA headquarters to go ahead with the launch when he had been warned about the risks.

[NGTOne]

The problem with NASA is that it's a US government agency - it has a massive bureaucracy, part of which only exists to serve the needs of the bureaucracy. This also means it has the US government's typical culture - i.e. "it's not my job". Somewhere among all the buck-passing related to Challenger (and there was A LOT of buck-passing), the launch date ticked closer, and everyone made the lowest-impact decision (at that juncture) - to launch.

The same thing happened with Columbia - they could SEE the damage, the analysts on the ground UNDERSTOOD that it was an issue, but the information got distorted so badly by the time it got to the decision makers that it didn't seem so bad. The rest is history. Kicker is, the same exact sequence of events happened once before - on another Shuttle flight (I can't remember which), they lost a tile or two on the way up. They took some pictures, came back down, and the people on the runway c***** bricks.

[Payload]

Don't even get me started on this subject. IMO Challenger was just as great of an administration failure as was the Foam strike incident. Even damage done, those people were savable. Though I suppose if the shuttle had a pad abort procedure then the Challenger crew was saveable as well. I still remember that day. I was eight years old and I got to watch NASA murder seven people live in my classroom.

No caliber of administration meeting is going to fix the fact that the O-rings won't work at that temperature. Nor will they fix giant holes in the leading edge of wings.

Considering NASA had a problem with the tiles falling off on their own accord just sitting in the VAB, one would think they would have instituted some tile inspection procedures before this.

Instead, they allowed them selves to be blinded by the fact that they had lost many tiles before and it never was an issue. Those sorts of failures tell you that you are headed toward the wrong side of the statistical probability scale.

Not that everything is going to be fine. That is a logical fallacy that humans apply when they get lucky a few times. Ask any Casino how it works. If it didn't, they wouldn't be in business.

[Requiem762]

The manufacturer actually predicted the possibility of a catastrophic failure similar to what happened to challenger as part of a risk assessment but the problem was considered extremely unlikely

[Mr Shifty]

The same thing happened with Columbia - they could SEE the damage,

Not true. They could see the tile come off and hit the wing in video, but they still have no idea what kind of damage was done to the wing. It was never imaged. Engineers lobbied for DOD assets (spy satellites) to be used to image it, but their requests were rebuffed. Columbia was the one orbiter with no robot arm, so they couldn't use the arm to inspect it. There was no EVA planned for that flight, so the crew only had emergency EVA training, and no one wanted to risk further damage to the wing for an unplanned inspection EVA. The accident investigation commission suggested two possible rescue scenarios (in retrospect): they could have spun up Atlantis and launched a rescue, or they could have jury-rigged a patch on the wing, depending on the type and degree of damage. Both scenarios would have been risky: Atlantis would have had to speed up its launch schedule by a month, and the rescue itself would have required many many hours of station keeping, with two shuttles meters apart, while emergency EVAs were conducted and supplies transferred across. The Columbia crew would have had to stretch their consumables to last a month on orbit; they probably would have been required to spend 18 hours a day asleep in order to keep their breathing slow enough to keep the LiOH CO2 scrubbers from overloading. And the decision to launch this expensive and risky rescue mission would have to have been made based on a necessarily contingent evaluation of the wing damage. And having the astronauts jury-rig a patch just seems far-fetched.

Regarding Challenger. STS-51L was not the first flight with O-ring problems. O-ring erosion and blow-by had been observed on several previous flights. The culture at Marshall was that "It didn't cause a problem this time, so it must not have been a big a deal as we originally assumed." (NASA administrators were kept out of the loop by Marshall regarding the ongoing O-ring problems.) This seems inexcusable, and it is, but the pressure in those organizations to push toward mission execution must have been enormous. (I am a former Navy nuclear power officer and have some inkling.)

Every accident is preventable in hindsight.

[Drunken Hobo]

I always wonder, how many times did they take a risk like this, only for nothing bad to happen? Nobody would bother to say anything if it worked out fine.

[Dkmdlb]

"It didn't cause a problem this time, so it must not have been a big a deal as we originally assumed."

To me this seems like the biggest problem. Some part operates outside of spec for several flights in a row, and then it's like "well, we know it isn't designed to function under these conditions, but nothing has happened yet, so..."

It's not that they couldn't have planned or foreseen for these things, it's that they *did* plan for them and *did* forsee them, but decided to continue anyway.

[rkman]

Does the engineers underestimated the risk?

No, engineers have warned NASA management on many occasions about the risk involved with the o-rings of the SRBs when launched outside of safe operating temperature range.

The decision to launch anyway was made by NASA management.

Space Shuttle Challenger disaster

Rogers Commission

http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster#Rogers_Commission

"One of the commission's best-known members was theoretical physicist Richard Feynman. During a televised hearing, he famously demonstrated how the O-rings became less resilient and subject to seal failures at ice-cold temperatures by immersing a sample of the material in a glass of ice water.

He was so critical of flaws in NASA's "safety culture" that he threatened to remove his name from the report unless it included his personal observations on the reliability of the shuttle, which appeared as Appendix F.[53] In the appendix, he argued that the estimates of reliability offered by NASA management were wildly unrealistic, differing as much as a thousandfold from the estimates of working engineers.

"For a successful technology," he concluded, "reality must take precedence over public relations, for nature cannot be fooled."[54]

[TheSaint]

Actually, if you really want to trace it back to the root of the problem (and get your blood boiling), the Challenger astronauts were killed by politics.

When the Shuttle was being contracted, Morton Thiokol was fourth out of four in the bidding for the Shuttle SRBs. Thiokol was building their SRBs in Utah, which necessitated breaking them down into segments that could be transported by rail. Aerojet's bid was to manufacture monolithic SRBs (no segments, no joints) at an existing facility in Florida within driving distance of KSC. But miraculously, Thiokol won the bidding. Why, you ask? Because the chairman of the Senate Space Committee happened to be the senior senator from Utah, Frank Moss. He threatened to kill the Shuttle funding unless Thiokol was awarded the contract.

In fact, the entire Shuttle design was shaped by politics. When NASA originally started looking at reusable shuttle designs back in the late 60s and early 70s, they were looking at SSTO and reusable first stage designs with stub wings. When they went to the administration looking for funding, Nixon balked at the price and told them to see about sharing the costs with the Air Force. The Air Force wanted a reusable vehicle as well, but one of their requirements was for the vehicle to be able to launch, execute its mission, and then land at the end of its first orbit. This required a cross-range gliding capability of over 1,000 miles, far beyond what the stub-wing designs NASA wanted could provide. So, they settled on the large delta-wing configuration you see in the final Shuttle design. But, adding all that additional weight in wings and structural bracing, they could no longer support a SSTO, or even a reusable first stage design, so they went with the now familiar stage-and-a-half design with the disposable fuel tank and reusable SRBs. And then, after the design phase was completed and contracts were finalized, the Air Force pulled out of the project, choosing instead to rely on expendable boosters. (Which is why the Shuttle launch complex at Vandenberg was never completed.)

All in all, I think space exploration is much better handled by private corporations. There are far fewer shenanigans.

[goldenpeach]

The other solution would be to give all the power to the engineers:they can do whatever they want as long as it fit the budget.

Of course,no politician will accept to lose their power

[ZingidyZongxxx]

Actually, if you really want to trace it back to the root of the problem (and get your blood boiling), the Challenger astronauts were killed by politics.

All in all, I think space exploration is much better handled by private corporations. There are far fewer shenanigans.

I hope that more companies become involved in space exploration. Competition drives innovation, and if a single country or company is controlling so much then there is no competition, and therefore no need to innovate.