Challenger engineer who warned of space shuttle disaster dies aged 89

Daily Mail ^ | 03/22/2016 | HANNAH PARRY

[Charles Martel]

IIRC they were forced to redesign the O Rings in order to conform to some EPA mandate.

The O Rings that would have kept the Challenger crew alive were banned because they contained some chemical that the extremists at the EPA didn’t like.

It sounds like you're confusing the Challenger's SRB O-rings with Columbia's insulation and ice impact problems. The latter was the one where NASA had a waiver and could have used the older formula (with non-EPA-approved chemicals), but chose to use the "green" formula.

I don't recall any discussion of the o-ring material being compromised by EPA meddling (though of course, I wouldn't really be surprised at such a revelation).

[cherry]

its posters like you that make FR a treasure....knowledgeable about so many things....

[chimera]

When I first saw the design for the shuttle orbiter my thought was, man, that heat shield is just hanging out there, nothing covering it. Until then all of our capsule-type spacecraft kept the heat shield covered during powered flight. Gemini and Apollo kept the heat shield protected up until almost the moment it was used (except for a brief time on Apollo 13, after SM jettison the CM and LM flew for the only time as a joined unit). The Mercury capsule heat shield was partially covered by the retro pack after release from its launch vehicle. Seemed kind of a risk to leave that heat-deflecting/absorbing surface just bare to whatever would befall it.

[Moonman62]

I believe on a previous flight a hole burned through the wing that was caused by a foam strike. In that case the location wasn’t as critical and the orbiter returned safely.

Halfway decent management could have prevented both Shuttle tragedies regardless of any regulations. The Shuttle was known to be a dangerous design so they should have been diligent.

[chaosagent]

They had had burn-thrus before, but the gasket melted and flowed into the gap, sealing the leak, as it had previously, and as it was designed to do.

Here is the sequence:

1. It was an extremely cold, wet winter.

2. Technical problems kept Shuttle on pad longer than usual.

3. Freezing weather at launch time.

4. There was an SRB burn-thru on Ignition as had happened before

5. After a second, the gasket flowed and resealed as it had numerous times before.

6. No more problems until throttle-up after Max-Q.

7. Then just as they throttled back up to 104% power, the highest upper air wind shear ever recorded buffeted Shuttle and rocked the entire stack.

8. SSME gimbaled over to correct

9. But rocking the stack reopened the previous burn-thru.

First Bad Luck:

Extreme High Winds at Throttle Up

Second Bad Luck and Primary Cause:

Burn-thru was located on the minority portion of the arc opposite the ET (External Tank). If the burn-thru had occurred on the ~ 300 degree arc not opposite the ET, the shuttle would have achieved orbit with no problem. The slight loss of thrust from the SRB burn-thru would not have been a problem.

It was only sheer bad luck that the burn-thru occurred where it did, no other reason.

And don’t even start about how the SRB’s were segmented to start with. NASA wanted to build the SRB at the Cape, but politics dictated that the Shuttle project largess be spread around to other states, including Utah where the SRB’s were built.

Unfortunately, due to a non-segmented SRB being too large to be transported, due to tunnels and overpasses, they were segmented.

Otherwise, no segments, no burn-thru, no explosion.

[chaosagent]

Thanks.

I had the fortune, or misfortune, to be there at the time.

[Pelham]

That could well be. My memory of it all is vague and it’s likely I could be confusing the two events.

[fieldmarshaldj]

RIP.

[NonValueAdded]

well said