The Wrong Stuff: NASA Astronaut on Making and Fixing Mistakes | Hacker News Reader

The Wrong Stuff: NASA Astronaut on Making and Fixing Mistakes

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83 pointsrfreytag31 comments

I never knew the Challenger disaster crew survived the explosion. It's a pretty damning indictment of institutional politics that steps couldn't be taken for similar situations to be non-fatal.

I used to be a mechanical engineer for several space shuttle missions. You're missing a critical element. Human space flight is insanely dangerous with today's technology. Astronauts accept this and NASA's engineers accept this. The safety requirements for a shuttle launch are voluminous and arcane - to the point where they restrict the freedom of engineers to solve problems to a significant degree. Most people don't know that spaceflight technology has barely improved since the 60's. The primary reason is safety.

That a shuttle (and it's crew) blows up is regrettable, but when you strap a cargo truck to a giant tank of hydrogen and light it on fire, someone is going to die from time to time. It's not like they don't know what they're getting into.

Figuring out how to keep the crew alive after the shuttle's main tank explodes is just a bad idea. Wouldn't it make more sense to figure out a way to keep the rockets from coming apart in the first place? How many additional failure points would you introduce by creating a failsafe for that unlikely case (of which there are thousands if not millions).

Of course we should learn from failures, but the surest way to kill the space program is force it to be safer. If anything, they need to inject more risk into space flight so that better technologies can gain the ever-elusive "flight heritage". Trust me, astronauts would still line up for a chance to fly even if you doubled the risk of death.

> I used to be a mechanical engineer for several space shuttle missions.

I voted you up for this sentence alone. It makes anything else that follows that you say inherently more valuable to the discussion. thanks for contributing.

I would hope my comments stood on their own, but sometimes it's necessary to shed some light on the bias inherent in one's comments... I can't pretend to be an objective observer on this one.

It's not about the ability to find astronauts to accept the risk.

It's about the blow to national prestige and to NASA when such a disaster happens. The public will not abide a spacecraft with the flag on it, crashing.

That is absolutely true. The public cannot handle the truth, to paraphrase a fictitious Marine. But the proper way to go about this is not to pretend that it is safe, which causes people to wonder what's wrong with NASA, but rather to embrace the risk, so that people understand what is going on.

If Wikipedia is to be believed, even if a Challenger-like disaster could be made survivable, it would require quite radical and undesirable changes to the orbiter.

http://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disast... http://en.wikipedia.org/wiki/Space_Shuttle_abort_modes#Eject...

NASA playing hide-and-seek with the true fates of the Challenger crew is deplorable, but not taking the steps you describe - before and after the disaster - was a conscious acceptance of risk.

the difficulty isn't just making this accident survivable, it's making any other accident at any other stage of the flight survivable.

So any escape system that would work for the specific Challenger failure - supersonic but at regualr aircraft altitude - wouldn't work for say a pad explosion, or a failure at higher altitude, or a failure where the boosters didn't separate, or a crash on landing or .....

Fitting a dozen different ejection seats to swap between during takeoff and landing is tricky!

Not really. Zero-zero ejection seats have been around for decades and function from zero altitude and airspeed to supersonic speeds and higher altitudes (50,000+ ft). These will work during crashes. The F-35 and AV-8B can operate at low enough speeds (hover, or hover transition) that the canopies are laced with explosive cord to shatter the glass (polycarbonate) out of the pilot's way (normally, the canopy would fly aftward from forward flightspeed). SR-71 pilots wore space suits so that they could endure such high altitude egresses, which would certainly protect at lower altitudes as well. We have ejection systems that work in most flight regimes. I don't see significant reasons why a crew escape capsule would not work for even higher altitudes and speeds. Not saying it would be easy, though.

For reentry safety, the best approach IMO is reducing reentry speeds via a lifting body fuselage. This is what SS1 uses. With drag bodies (e.g. Apollo capsule) there's all this worry over heatshields and reentry angle; with a lifting body, the vehicle glides into the atmosphere subsonically and heating is a nonissue. SS1 has minimal heat shielding, and no active cooling. A capsule is apparently simpler to design and easier to understand than something more airplane-like, but so is an ornithopter over a fixed-wing aircraft (kids ask how planes fly without moving their wings, because flapping flight is more obvious). One design requires delicate control and handling though, while the other is elegantly robust, more reliable, and safer.

Ejector seats would work for a challenger stage accident. The first shuttle with only 2 pilots on board did have aircraft style ejector seats. The problem comes when you have a crew of 7 on two levels - you could have down/side-ward firing seats, as used on some B52 variants, but that compromises the heat shield.

But the most dangerous part of the flight is on the pad, a seat capable of firing you horizontally far enough to be clear of an explosion on the pad would be difficult - you would probably need the entire crew compartment to eject on it's own set of rockets - but this wouldn't work on landing, the other dangerous stage. Then there is the added danger of the rest of the flight - when inside the pressure hull you have the rockets necessary to blow a 2ton escape pod 3-5km clear of a pad fire.

About the Challenger accident, don't forget to read the fantastic report by Richard Feynman : http://www.ralentz.com/old/space/feynman-report.html

Saftey was improved after the disaster.

Failure rate went from 4% to 1.8% according to the interview.

Probably due at least in part to treating the explosion as something other than a "blameworthy act."

I wonder, though, if they've taken steps to make a launch failure survivable. If the Challenger situation repeated itself, what would be the odds of the astronauts living through it?

After the Challenger accident, a jettisonable hatch, personal oxygen systems, parachutes, rafts, and pressure suits were added to ascent and entry operations of the space shuttle.

http://www.nasa.gov/pdf/298870main_SP-2008-565.pdf

This was the system where after the craft explodes and is falling to earth at mach2 - you jettison a hatch, extend a boom, put on safety harness, clip the harness to the boom and slide out to then end (to clear the wings and tail) jump off and open your parachute?

No mention of what happens if something goes wrong while you are still attached to 2Million lbs of liquid hydrogen/oxygen.

I remember the laughter at the time ....

NASA added the safety systems after Challenger because the crew survived the explosion.

Similarly, they added tile repair kits after Columbia.

Zero.

Remember there is no need to make an accident survivable because an accident can't happen "Failure is not an option" and lots of other macho chest beating.

If the Titanic had been built by Nasa it would have had no lifeboats, a crew of 10,000 safety inspectors but would still have hit the iceberg.

As someone else has said making an ejection system that could resuce the crew at each stage of the flight is very difficult.

What's more troubling (although not surprising) is Nasa's 'news management' in keeping this a secret because of fear of bad publicity.

20 years later this attitude hadn't changed with the Columbia - when Nasa prevented any in-orbit inspection of the damaged tiles. Just in case they then had the PR nightmare of a crew that were likely to die on re-entry and no way of rescuing them.

Secret? They aren't shouting it from the rooftops, but I have known this ever since they published the report.

This dovetails nicely with Atul Gawande's book "The Checklist Manifesto". Certainly we can't completely automate medical diagnosis and treatment, but we could go a lot further than we have thus far.

I thought one of the best quotes from the interview was Telling people to be careful is not effective. Humans are not reliable that way. ... You need a solution that's not about making people perfect.

In related space matters: the ISS has a webcam!

Last week I saw a hurricane from space. Yesterday, they were struggling to get Win2000 to connect to a LAN.

http://www.nasa.gov/multimedia/isslivestream.asx

They used to have SSTV (http://en.wikipedia.org/wiki/SSTV) as well. I never successfully captured one but I have from other SSTV stations. It's a very cool feeling to receive pictures from someone hundreds of miles away over "nothing" (radio). I can only imagine the feeling receiving photos directly from the ISS.

Wait, what is that a webcam of? I see a computer monitor, nothing spacey at all, and hearing Russian radio chatter.

Ah, yeah, right now it's switched to a map showing the position. Sadface. But the last few days it's been showing an interior view, and before that mainly exterior shots. You get a mission overlay a fair bit, too, which is a shame - I assume this is when video signal is lost.

The Russian radio chatter is ground talking to astronauts in Russian. There's also English radio chatter, too.

There are spacey things going on right now! Someone is floating through the air!!

I've read an article on the very same subject a couple of years ago. It started with the maiden flight (and crash) of the B-17, and how it then became the first plane with a check-list. What was it? Wired? The Atlantic?

BusinessWeek: http://www.businessweek.com/magazine/content/10_08/b41670780...

More about the B-17 history: How the Pilot's Checklist Came About: http://www.atchistory.org/History/checklst.htm

This is all applicable to our industry as well.

I've tried to foster a culture on my team, where nobody's in trouble when we find a bug. The only think I want to hear about is (a) how do we fix it, and (b) how do we prevent it next time.

The only thing that's going to be trouble is trying to hide a bug.

The title must be an acknowledgement of the oft-mentioned "They Write the Right Stuff": http://www.fastcompany.com/magazine/06/writestuff.html

Actually, they both reference the 1979 Tom Wolfe book:

http://en.wikipedia.org/wiki/The_Right_Stuff_%28book%29

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