Grissom, White, Chaffee - 50 years ago

[LordFerret]

I remember the day. Salute gentlemen. RIP

https://phys.org/news/2017-01-nasa-apollo-capsule-hatch-years.html

[Bill Phil]

Truly a sad day...

Even so, their sacrifice helped reveal major problems in the design of the Apollo Block I spacecraft. Their deaths may have saved the crews of subsequent flights. Their deaths were not in vain.

[Exploro]

Last year I read "The Right Stuff". One part in particular noteworthy; as it was sadly ironic considering what lead to his death. Grissom was touring the Convair plant building the Atlas rockets to be used in the Mercury program. He tells the production team to "Do good work"; inspiring them to build flawless machines to ensure the safety of the astronauts that would ride atop them. When I read that I reflected on the flaws and faults found in the CM of the Apollo he and his two crewmates died within.

[ZooNamedGames]

50 years ago three men board the Apollo capsule during a 'plugs out' test, showing that the capsule could operate under it's own power. To add to the test's realism, they pumped the capsule full of oxygen at sea level. This led to a fire spreading within the capsule, killing Gus Grissom (Mercury and Gemini veteran), Ed White (first American to EVA), and Robert Chaffee. The astronauts who would have become the first astronauts to fly during Apollo, until this.

The fire was caused by a wire that had become frayed underneath Grissom's seat from the panel door being opened and closed over time as it was used. When a current ran through it, it arched to nearby Velcro which the investigations revealed to have too much of as when Velcro is pressurized by oxygen, it becomes flammable. Along with the pure oxygen atmosphere, it become a fireball. The crew attempted to follow procedures, with White climbing over Grissom's seat to try and open the hatch, but seeing as the hatch opened inwards and was sealed by pressure, it become impossible.

Despite the length of this, it took 15 seconds from first mentioning of the fire "We've got a fire...", to the hull breaching.

The greatest irony in all of this being; in Grissom's first spaceflight aboard Liberty Belle 7 during Mercury, his capsule's hatch blew after splashdown and forced him to bail out of his capsule earlier than intended and due to open valves in his suit, caused him to take on water and nearly drown while he waited for recovery. As such an investigation team found that capsules with explosive hatches were unsafe and decided to remove them. If the crew had a hatch with explosive bolts, they likely would've escaped; Grissom would've become one of the first astronauts to land on the moon and they'd lived a long lifetime.

Yet without their sacrifice, we may have discovered the very flaws that led to it in an even worse fashion. Possibly losing crews in space.

Rest in peace. Many have forgotten your sacrifice, but not everyone has.

 

Edited January 27, 2017 by ZooNamedGames

[Dafni]

The Apollo program, arguably the greatest and most dangerous missions ever. Its heroes should never be forgotten. From Gus to Gene.

Rest in peace Virgil "Gus" Grissom, Edward H White II and Roger B Chaffee.

Edited January 27, 2017 by Dafni

[benzman]

I remember reading in either Chris Kraft's book or Gen Kranz's book that, had he lived, Gus Grissom would most likely have been the first man on the moon.  Apparently, it had come down from Somewhere on High that it was desired that the first man on the moon should be one of the original seven Mercury astronauts.  By the time of Apollo Alan Shepard and Deke Slayton had been grounded for medical reasons, Scott-Carpenter had upset people and been told that he would never fly again, Gordo Cooper was thought to be too much of a loose cannon, John Glenn had left to go into politics, Wally Schirra was loudly telling everyone that he was leaving NASA after flying the first manned Apollo flight, and that only left Gus, which is not as bad as it sounds as some people, including Chris Kraft, regarded Gus as the best, natural born stick and rudder man of them all.

 

[Frybert]

Overlapping threads merged.

[DerekL1963]

48 minutes ago, benzman said:

I remember reading in either Chris Kraft's book or Gen Kranz's book that, had he lived, Gus Grissom would most likely have been the first man on the moon.  Apparently, it had come down from Somewhere on High that it was desired that the first man on the moon should be one of the original seven Mercury astronauts.

I don't think it was either...  I think that was Deke.  (Who was also close friends with Grissom.)   He was absolutely determined that one of the Seven would land on the Moon.   When Sheppard came off the DL in May of '69, Deke assigned him directly to Apollo 13 - despite his lack of experience and the lack of time for training.  HQ objected (both because of Shepard's inexperience and the inexperience of his crew overall), and Deke swapped the crews of 13 and 14 to appease them.

[munlander1]

Was the cause of the fire every determined? I heard it was caused by a spark, but in gene kranz's book he said it was never determined.

[StrandedonEarth]

12 hours ago, ZooNamedGames said:

they pumped the capsule full of oxygen at sea level.

I had read somewhere that the capsule was designed to operate with 5 psi pure oxygen. For the test, they pumped up the capsule to 5 psi positive pressure (on top of sea level pressure, 14.7 psi). So the capsule was full of pure oxygen at almost 20 psi. The oxygen was almost four times as dense as designed. At that pressure/density, things were just looking for an excuse to burn, and burned four times as fast as they would have during normal operation.

The atmosphere is 21% O₂, so the partial pressure of oxygen is normally 3 psi. So there was more than 6 times as much oxygen available compared to a normal outdoor fire. It was a blast furnace in there.

Edited January 28, 2017 by StrandedonEarth

[LordFerret]

4 hours ago, munlander1 said:

Was the cause of the fire every determined? I heard it was caused by a spark, but in gene kranz's book he said it was never determined.

That is correct (Kranz), a single source of ignition was never resolved. If you Wiki search 'Apollo 1', it actually has a decent synopsis of the events; Search NASA history for more detailed writings.

[Frybert]

12 hours ago, StrandedonEarth said:

I had read somewhere that the capsule was designed to operate with 5 psi pure oxygen. For the test, they pumped up the capsule to 5 psi positive pressure (on top of sea level pressure, 14.7 psi). So the capsule was full of pure oxygen at almost 20 psi. The oxygen was almost four times as dense as designed. At that pressure/density, things were just looking for an excuse to burn, and burned four times as fast as they would have during normal operation.

The atmosphere is 21% O₂, so the partial pressure of oxygen is normally 3 psi. So there was more than 6 times as much oxygen available compared to a normal outdoor fire. It was a blast furnace in there.

Correct. The idea behind it all was that in space, 5 PSI pure oxygen would sustain the astronauts. The hatch was a holdover from when the CSM would land on the moon and thus was a pressure sealed hatch to save weight. In order to maintain the seal at sea level for the test the capsule was pressurized to a whole lot more than it was designed for. To quote an engineer "At this level, aluminum EXPLODES". The key thing is not 100% oxygen (this was used long after) but rather 100% pure oxygen  UNDER PRESSURE.

 

 

[StrandedonEarth]

9 hours ago, LordFerret said:

That is correct (Kranz), a single source of ignition was never resolved.

At 20 psi pure oxygen, you don't really need an ignition source as some things could spontaneously combust, especially oils. That's why you never use oil on the oxygen fittings of an oxyacetylene rig, or any pressurized oxygen fittings for that matter.

[magnemoe]

38 minutes ago, Frybert said:

Correct. The idea behind it all was that in space, 5 PSI pure oxygen would sustain the astronauts. The hatch was a holdover from when the CSM would land on the moon and thus was a pressure sealed hatch to save weight. In order to maintain the seal at sea level for the test the capsule was pressurized to a whole lot more than it was designed for. To quote an engineer "At this level, aluminum EXPLODES". The key thing is not 100% oxygen (this was used long after) but rather 100% pure oxygen  UNDER PRESSURE.

Yes, the eva suits uses 100% oxygen at 1/5 bar who is safe and limit how inflated the suits get. It also make the rebreather life support system simpler. 
Only issue is that the astronaut need an time to get from 1 bar air to 0.2 bar oxygen, not sure if this is needed the other way, think its the same reason divers need decompression stops 

And the idea of using over-pressure of pure oxygen was insane, why did they not test with air? think the life support system would simply lower pressure and increase oxygen level in space, this had to be reversed on return but then you could probably just open an valve and let air in. 

Edited January 28, 2017 by magnemoe

[LordFerret]

53 minutes ago, StrandedonEarth said:

That's why you never use oil on the oxygen fittings of an oxyacetylene rig, ...

I've seen an ox-acet rig go, although I don't know if it was from oil on any fittings. Pretty wild. Also seen the head knocked off a big nitrogen tank... very Kerbal-like rocket. Duck!

 

24 minutes ago, magnemoe said:

And the idea of using over-pressure of pure oxygen was insane, why did they not test with air?

The reason is a matter of record, and a part of the history of all this. An earlier test pilot died as a result of a bad oxygen/nitrogen (I think it was, don't quote me) mix, so it was decided to use pure oxygen. Remember, we didn't know too much about this stuff back then... just like your first few KSP rockets you built - we lost a few.

Edited January 28, 2017 by LordFerret

[munlander1]

11 hours ago, LordFerret said:

That is correct (Kranz), a single source of ignition was never resolved. If you Wiki search 'Apollo 1', it actually has a decent synopsis of the events; Search NASA history for more detailed writings.

Thanks