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

#181

Post by breidh » Sun, Aug 05, 2012, 4:13 AM UTC

ams6110 wrote: post #135

neurotech1 wrote: post #124

Earlier quoted context omitted.

> 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…

I wouldn't say the DC-10 problems of the 1970s forced McDonnell-Douglas out of the airliner business. They continued in business into the 1990s before being acquired by Boeing. The DC-10 itself was in passenger service until just a few years ago, and is still flown in freighter and military configurations.

The DC-10's legacy is really one of bad timing more than anything. Its direct competitor, the L-1011 suffered a very short production run for many of the same reasons, none of which involved safety.

The 1980s ushered in a new era of twin engined widebody aircraft and the phasing out of the flight engineer. These two trijets were consequently a difficult sell, although the MD-11 was competitive with the 747 briefly in the early to mid 90s.

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

#182

Post by JL2010 » Sun, Aug 05, 2012, 6:04 AM UTC

InclinedPlane wrote: post #173

JL2010 wrote: post #172

Earlier quoted context omitted.

Perhaps I should've re-worded my previous comment because I did not mean to suggest that we abandon manned missions forever or that we try to experience space vicariously through robots. I'll elaborate. There is tremendous risk involved in sending people to space, I'm sure those who sign up for it understand and accept that, but it's a tragedy when it goes wrong given the caliber of people who end up dying. The overh…

I think that's being overly and unnecessarily cautious. If we wait until there's no risk then we'll end up waiting far too long. There's always going to be some risk. There's a ton of risk just in getting out of the house and driving on the road. But there's risk in sitting on your ask at home too. Also, a great many astronauts are more than willing to take these risks. If you look at the Gemini program, for example,…

>There's a ton of risk just in getting out of the house and driving on the road. But there's risk in sitting on your ask at home too.

The risk factor involved in manned space missions versus a trip to the grocery store has got to be huge orders of magnitude in difference. This is an unfair, and frankly, useless comparison.

>if our choice was to explore the Solar System with a vehicle no safer than the Soyuz or to stay at home the choice has to be to explore, every time.

This is where I can't agree. You have to define "explore" - i.e. the particular objective of that flight on a case by case basis - and ask if it really warrants sending a human being up to do that job. Yes? Then by all means. Do it. No? Then find a safer alternative that accomplishes the same goal and that sheds the challenges of keeping a human being alive in a truly hostile and unforgiving environment. Also, I wouldn't consider sending an autonomous vehicle out to explore as "staying at home".

I get the emotional appeal... I just don't think it's rational for every case unless we really need a human's capabilities in space.

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

#183

Post by stcredzero » Sun, Aug 05, 2012, 2:21 PM UTC

alpine wrote: post #108

stcredzero wrote: post #104

Earlier quoted context omitted.

Most of it is kinetic energy.

Most of what is kinetic energy? Its job? A rocket that reaches escape velocity from Earth can have zero kinetic energy.

Most of what the rocket has to increase to take an object from the earth's surface to LEO. If you calculate the potential energy of a rocket in LEO and compare it to its kinetic energy, you'll find the latter is much larger. (I've already done this and posted it here.)

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

#184

Post by anovikov » Sun, Aug 05, 2012, 2:25 PM UTC

InclinedPlane wrote: post #130

neurotech1 wrote: post #124

Earlier quoted context omitted.

> 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 veh…

One problem i see with spacex is their propulsive landing feature. What if things go wrong at that point, like a software or a sensor problem causing it to descend at a speed too high/not realizing it approaches the surface/just hovering and expending the propelland quickly? If landing on land, they don't have any backup, and astronauts are doomed, falling from even very low altitude (30-50ft) will be fatal.

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

#185

Post by JackpotDen » Mon, Aug 06, 2012, 4:35 PM UTC

JL2010 wrote: post #172

InclinedPlane wrote: post #171

Earlier quoted context omitted.

Is anything necessary? It's easy to define away the necessity of anything, even living. The point of manned space exploration is ultimately about colonization. The point is for people to go, to do, to live. And you can't get that with robots no matter how hard you try. We can no doubt learn the secrets of the Universe through robots, and we very much should do so. But there is more to the Universe than just studying…

Perhaps I should've re-worded my previous comment because I did not mean to suggest that we abandon manned missions forever or that we try to experience space vicariously through robots. I'll elaborate. There is tremendous risk involved in sending people to space, I'm sure those who sign up for it understand and accept that, but it's a tragedy when it goes wrong given the caliber of people who end up dying. The overh…

> to conduct research experiments.

Whether it seems nice or not, one of the experiments being conducted by humans in space is the effects of being in space for a prolonged amount of time on human beings.

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

#186

Post by lutorm » Wed, Aug 08, 2012, 12:33 AM UTC

JPKab wrote: post #33

austenallred wrote: post #12

I'm impressed that there's $440M left in NASA (or over $1 Billion with Sierra Nevada and Boeing included) to fund a new space shuttle, somehow I was under the false impression that there wouldn't be any more of that type of thing. Hats off, Elon Musk. Hats. Off.

It's a travesty that Boeing got more than SpaceX, and Sierra Nevada got any money at all. I can't wait to see those two bloated, horrifically managed behemoths fail miserable with the money. The only reason NASA gave them anything was to shut up the congressman Boeing and Sierra have in their pockets. Remember this, because SpaceX, with slightly less money than Boeing, will produce FAR, FAR more.

Well, someone said "with the Boeing overhead, that's like them getting half the money that SpaceX got"... ;-)

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

#187

Post by lutorm » Wed, Aug 08, 2012, 12:38 AM UTC

alpine wrote: post #108

stcredzero wrote: post #104

Earlier quoted context omitted.

Most of it is kinetic energy.

Most of what is kinetic energy? Its job? A rocket that reaches escape velocity from Earth can have zero kinetic energy.

Something with exactly escape velocity from a body always has zero total energy. That's the definition of escape velocity.

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

#188

Post by lutorm » Wed, Aug 08, 2012, 12:44 AM UTC

danielweber wrote: post #95

zevets wrote: post #86

Earlier quoted context omitted.

It's not that high. A lot of the losses in take-off aren't the consequence of drag. I think I saw on wikipedia that the aerodynamics losses are only 1-200 m/s of the delta-v budget.

I surely don't want to use this site as gospel (especially since I can't pull up a better version of that graph) but it claims that the losses are around 25% at sea level. http://www.nasaspaceflight.com/2012/07/commercial-shows-reig... Going by raw math, if the Earth were a perfect magic sphere with no atmosphere, you could attain "orbit" at ground-level by accelerating to 7.90 km/s. Then you could Hohmann to LEO wit…

They aren't independent, though. "Gravity drag" comes from the fact that you need to put in 1G just to remain at constant speed. It's thus most efficient to have as high acceleration as possible. Unfortunately the aerodynamics work in the opposite direction: you don't want to go fast because that increases aero losses and there's a limit to how fast you can go in the lower atmosphere without breaking up. So the combined effects probably mean that the net loss is quite a bit larger than you could achieve if you only had to minimize one of them.