SpaceX wins $440M contract with NASA to develop Space Shuttle successor • Hacker News Board

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#121

Post by natep » Fri, Aug 03, 2012, 11:37 PM UTC

ballooney wrote: post #76

natep wrote: post #50

Earlier quoted context omitted.

Actually, the largest cost is building a whole new structure. With a fully reusable rocket (as SpaceX is going to use), the only costs are fuel and maintenance, which is more expensive than an airplane (~$50k per flight, IIRC), but negligible compared to the initial cost of designing and building the structure. Could you imagine if airplanes were single use? There would no way Southwest could achieve a 45-minute turn…

> With a fully reusable rocket (as SpaceX is going to use) This is the sort of thing where you need to be careful with what you infer, the the sort of thing that often causes engineers to be overconfident in performance and reliability estimates.In reality, they're doing some very initial experiments in vertical landing with a view towards exploring reusability. That is different to your implication that reusability…

> your implication that reusability is a done deal.

The plan is full reusability, except for a few parts that are lost as each stage separates from the rest, and fuel. There is no plan B. http://www.transterrestrial.com/?p=27574

And re: testing, I misspoke. By "part" I didn't mean component, I meant to say "system" but had in mind testing each part of the mission and contingency plan (in addition to end-to-end tests). I, and the engineers at SpaceX, are aware that most failures come from interactions between systems. And by "extrapolate", I didn't mean extrapolate from one part to the entire system, but from N tests to the N+1th test (because when you test as you fly and fly as you test, the actual mission is just another test).

Also, you conflate 'safety' with 'complete system success.' Apollo 15 had a safe, successful reentry, despite the single parachute failure, because there was designed-in redundancy. You can expect similar from SpaceX.

But you are right in that assigning any sort of reliability number is rediculous. On my project, we have analyzed every possible failure scenario we can think of, and come up with contingency plans on top of contingency plans, until we get to the point where so many things would have to be wrong in order for our plan to be used that it's not worth the effort, and we would think on our feet at that point. But still, nobody has bothered putting out a percentage chance of mission success. And nobody has asked the launch vehicle for a percentage chance of correctly inserting us into our desired orbit.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#122

Post by natep » Sat, Aug 04, 2012, 12:01 AM UTC

wtracy wrote: post #100

alpine wrote: post #88

Earlier quoted context omitted.

He has no plans to sell It is a brave man that gets in to bed with the government thinking he can withstand the intolerable pressure they can bring, if they decide, to bend his will. Nationalisation... How likely do you really think that is? Surely, it is for the oracles to strike a claim on future events, but when you consider gold confiscation in the 1930s, oil nationalisation in the 1950s, the absurd nationalisati…

How many NASA contractors have been nationalized in the past?

None that I can think of or find, and space firms get bought all the time. I worked with someone who stayed in the same building for many years as it changed hands multiple times. Nobody ever told me they worked for "X, now NASA"--it was usually "Hughes, now Boeing" or "Y, now L-3."

Individual contractors, however, can and do get hired by the government, but it depends on the NASA center. Most of the people at Goddard are actually contractors, not government employees, I believe.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#123

Post by [deleted] » Sat, Aug 04, 2012, 12:01 AM UTC

wtracy wrote: post #100

alpine wrote: post #88

Earlier quoted context omitted.

He has no plans to sell It is a brave man that gets in to bed with the government thinking he can withstand the intolerable pressure they can bring, if they decide, to bend his will. Nationalisation... How likely do you really think that is? Surely, it is for the oracles to strike a claim on future events, but when you consider gold confiscation in the 1930s, oil nationalisation in the 1950s, the absurd nationalisati…

How many NASA contractors have been nationalized in the past?

[deleted]

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#124

Post by neurotech1 » Sat, Aug 04, 2012, 12:02 AM UTC

InclinedPlane wrote: post #85

btilly wrote: post #20

It is easy to use superlatives like "safest rocket ever designed". But a lot of stuff can go wrong - fast - when you're sitting on a big pile of potential explosives that under other circumstances you'd keep a safe distance from. Until they actually achieve it, you shouldn't throw the superlatives around. I will be the first to applaud if SpaceX achieves this goal. I am certain that they want to achieve this goal. Bu…

Here's why it's likely the manned Dragon capsule will be one of the safest manned spacecraft in history. First, the Falcon 9 so far has a 100% success rate. The rocket engines are designed to be able to handle having a stainless steel nut pass through the fuel lines without shutting down. More so the vehicle is designed to be able to withstand an engine exploding, even at launch, without damaging the other engines an…

> Here's why it's likely the manned Dragon capsule will be one of the safest manned spacecraft in history.

Lets not forget that the two shuttle accidents were as much about a human factors failure, as a systems failure. Make no mistake about it, If a company like SpaceX ever got complacent about safety, it is game over. They will not get a second chance. Remember McDonald-Douglas, and how many DC-10 accidents, that basically forced the company out of the airliner business.

The Launch Escape System on a Soyuz capsule has been used once, in 1983 http://en.wikipedia.org/wiki/Soyuz_T-10-1

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#125

Post by alpine » Sat, Aug 04, 2012, 12:25 AM UTC

natep wrote: post #120

alpine wrote: post #90

Earlier quoted context omitted.

Now extrapolate my argument to the difference between the beach at the Dead Sea and the launch point for earth-orbiting payloads on a space elevator.

Let us know how building that space elevator goes http://www.youtube.com/watch?v=_2M73aXuORI

Why don't you brief me. I'd be interested in how you invalidate my argument in the above.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#126

Post by btilly » Sat, Aug 04, 2012, 12:26 AM UTC

nitrogen wrote: post #117

ballooney wrote: post #76

Earlier quoted context omitted.

> With a fully reusable rocket (as SpaceX is going to use) This is the sort of thing where you need to be careful with what you infer, the the sort of thing that often causes engineers to be overconfident in performance and reliability estimates.In reality, they're doing some very initial experiments in vertical landing with a view towards exploring reusability. That is different to your implication that reusability…

It's the lack of full-scale, realistic tests of complete systems that cause problems. There's just not the money for it nowadays. For example, Orion's crew vehicle had budgeted 2 aeroplane parachute drop tests. Apollo's landing module had over 230. Interestingly, they recorded anomalies on over 210 of those. I would argue that modern designs that learn from the mistakes of past designs require less testing. Maybe it…

First of all, what do you think you're arguing against? The argument isn't that SpaceX can't do better than existing designs. It isn't that they aren't trying. It isn't that they aren't going around this the right way. It is simply that we do not have data right now to have any real idea how well they actually will do.

Do you have anything to counteract that?

As for the rest, do you have any idea how ridiculous your position is? Based on a misinterpretation of a popular essay about basic science, you conclude that experimental data is less important now than previously. And you're doing this when arguing with an expert in parachute design who is well aware of the current limits of simulations, and several examples of what has happened when actual engineers tried to extrapolate from past designs and models to predict what would happen with a future design.

Furthermore you're doing this with willful ignorance of the fact that every area of technology where people actually achieve high reliability, it is done by people who place a lot of emphasis on actual data from experiment. Simulations are a supplement, not a replacement for that.

Finally your claim, new designs have the benefit of learning from every single previous failure is plain wrong. Anyone who studies this stuff will tell you that people keep making the same types of boneheaded mistakes over and over again. And, people being people, it is hard for us to recognize when we've made that particular type of error again. Therefore we create procedures to automatically catch errors that our organization has proven to have a tendency to make. Those procedures need to include live tests. Furthermore our expectation should be that we will continue to screw up in similar ways to what we have done before, and not that we've learned from the past and now only make more exotic errors.

All of that said, let me repeat. The people working at SpaceX absolutely know this. They seem to be on course to potentially do better than has been done in the past. But until they accumulate an accident record, we won't know how well they've done. (And at this point their designs are in sufficient flux that it will be years before we really can establish a good baseline.)

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#127

Post by btilly » Sat, Aug 04, 2012, 12:27 AM UTC

stcredzero wrote: post #97

btilly wrote: post #46

Earlier quoted context omitted.

So what you're telling me is that they have a more sophisticated system than previous ones with sophisticated backups. When it comes to reliability sophisticated can go either way - it can be better or can just give more things than can go wrong. For instance what happens on your vertical landing if a sensor malfunction causes the software to decide that the rocket is not vertical unless it is at a 20% tilt? (Don't l…

> Until you have actual experience with the weird stuff that goes wrong in the field, you do not really know what is going to go wrong. And the more complicated the system is, the more true this fact is. A great lesson for software devs.

Where do you think I learned it? :-)

But I've since learned that it is true in areas far from software.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#128

Post by droithomme » Sat, Aug 04, 2012, 12:43 AM UTC

jlgreco wrote: post #62

droithomme wrote: post #47

Earlier quoted context omitted.

Actually White Star claimed it was "designed to be unsinkable", not that it was. And this was after describing a long list of safety features. It's a very dangerous attitude, to claim a priori that your design is safer. The Titanic was so safe that it was not necessary to carry enough life boats for all the passengers. That's how safe it was. Once your focus is on the incredible confidence you have in the safety of y…

The difference in this situation of course is that SpaceX is claiming that their rocket will be safe because they are adding more lifeboats (in other words, they are bragging about their planned abort systems). They are not claiming to be designing a rocket that cannot fail, but rather one that fails safe (though low failure rate is undoubtedly a high priority for them.) I do not see how such an attitude could possib…

> Is your issue that the are trying to make it the safest, or that they said that they are trying to make it the safest?

The article doesn't say they are trying to make it the safest and it doesn't say they said they are trying to make it the safest.

The article says it will be the safest, even though it hasn't even been tested in flight.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#129

Post by CamperBob2 » Sat, Aug 04, 2012, 12:47 AM UTC

btilly wrote: post #46

ceejayoz wrote: post #25

Earlier quoted context omitted.

> It is easy to use superlatives like "safest rocket ever designed". But a lot of stuff can go wrong - fast - when you're sitting on a big pile of potential explosives that under other circumstances you'd keep a safe distance from. Until they actually achieve it, you shouldn't throw the superlatives around. This claim revolves more around the fact that the rocket can do a powered abort at any time, I think. It's pure…

So what you're telling me is that they have a more sophisticated system than previous ones with sophisticated backups. When it comes to reliability sophisticated can go either way - it can be better or can just give more things than can go wrong. For instance what happens on your vertical landing if a sensor malfunction causes the software to decide that the rocket is not vertical unless it is at a 20% tilt? (Don't l…

I wouldn't want to put my life in the hands of someone who trusted his own software, so I'm going to say no.

I like that. There are a million ways you can answer a given interview question that will cost you the job, but there are also a few ways you can make me end an interview and make you an offer on the spot. Under the right circumstances, that answer would be one of those.

And you have to pray that they didn't miss something.

I don't have to do any such thing.

Re: SpaceX wins $440M contract with NASA to develop Space Shuttle successor

#130

Post by InclinedPlane » Sat, Aug 04, 2012, 12:51 AM UTC

neurotech1 wrote: post #124

InclinedPlane wrote: post #85

Earlier quoted context omitted.

Here's why it's likely the manned Dragon capsule will be one of the safest manned spacecraft in history. First, the Falcon 9 so far has a 100% success rate. The rocket engines are designed to be able to handle having a stainless steel nut pass through the fuel lines without shutting down. More so the vehicle is designed to be able to withstand an engine exploding, even at launch, without damaging the other engines an…

> Here's why it's likely the manned Dragon capsule will be one of the safest manned spacecraft in history. Lets not forget that the two shuttle accidents were as much about a human factors failure, as a systems failure. Make no mistake about it, If a company like SpaceX ever got complacent about safety, it is game over. They will not get a second chance. Remember McDonald-Douglas, and how many DC-10 accidents, that b…

The Space Shuttle was a far less reliable system from a fundamental design perspective. The size of the wings, the nature of the thermal protection system, the insulating foam and the use of a super-cryogen as fuel, the side-by-side staging, the use of solid fueled boosters on a manned launcher, etc. Engineering estimates show that we were incredibly, incredibly lucky to have the Shuttle safety record we did, the vehicle was a death-trap. We almost lost Atlantis in 1988 and Discovery in 2005 to the same thing we lost Columbia to, and we almost lost several shuttles in the early 80s to the same fate that doomed Challenger.

Of course if an organization ever gets complacent about safety then things can go downhill, but in the case of SpaceX they have a fundamentally more robust vehicle design, a system with more and safer abort scenarios, and every possible reason to maintain a high degree of vigilance about safety (if for no other reason than their company's image and financial bottom line).