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SpaceshipTwo crashes shortly after Mojave test flight

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Re: SpaceshipTwo crashes shortly after Mojave test flight

#171

Post by JoeAltmaier »

gohrt wrote: post #170
winslow wrote: post #162

Earlier quoted context omitted.

Really... You are going to trust the entire Soviet space program compared to the engineers behind this project? I really don't think they were being reckless with having pilots. Ultimately, their plan was to take other patrons up to space. You will need personal (experienced space flight attendants) while conducting the flight. This is obviously tragic and my thoughts go out to the families affected. However, when yo…

So the pilot died in order to make Richard Branson's space tourists have a safer and more enjoyable weekend. Cool.

The pilot died trying to make a cheap, reusable orbiter a reality. The tourists are there to help pay for it.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#172

Post by zepolud »

winslow wrote: post #162
zepolud wrote: post #152

Earlier quoted context omitted.

"These people" that designed the spaceplane didn't put their lives on the line, they put the lives of the pilots on the line. And I would trust the judgment of the engineers at Boeing, Sierra Nevada, SpaceX, Lockheed-Martin and the entire Soviet space program over theirs.

Really... You are going to trust the entire Soviet space program compared to the engineers behind this project? I really don't think they were being reckless with having pilots. Ultimately, their plan was to take other patrons up to space. You will need personal (experienced space flight attendants) while conducting the flight. This is obviously tragic and my thoughts go out to the families affected. However, when yo…

Please read the context of the first post--I'm referring to the engineers behind the specifically mentioned Buran program, an autonomous spaceplane that launched, flew and landed with no crew.

If the Soviets deemed it too risky for human pilots and managed to automate it 25 years ago maybe that should put it into perspective just how risky and reckless what Virgin are doing is.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#173

Post by dandelany »

termain wrote: post #159
marze wrote: post #69

Earlier quoted context omitted.

Some say this is an "inevitable" result of pushing boundaries. No. This is the result of a poorly managed program. What they are doing is much easier than the Apollo program, which was well managed and had no in-flight failures that resulted in loss of life, while accomplishing an infinitely harder task. This is a tragedy, obviously. But the program is about six years behind schedule, been going for 10 years. The mos…

"The most stupid thing they've done is stay with an experimental rubber/nitrous hybrid engine this whole time, instead of switching to liquid/liquid engine, a well proven technology." 1. They didn't stay with rubber/nitrous. 2. Like the sort used on Antares? "Seeing only the first paragraph, I already know that some rubber in the hybrid engine detached blocking the nozzle and causing the whole engine to explode." But…

Point 1 is a good one, point 2 is not. Yes, liquid engines like the sort used on Antares, Soyuz (most reliable rocket ever built), Falcon, Proton, Atlas, Shuttle, Delta, Ariane, Saturn, and nearly every other orbital launch platform ever. Liquid/liquid engines, by any measure, are orders of magnitude more stable and well proven than hybrid rocket engines.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#174

Post by jedmeyers »

7952 wrote: post #130
revscat wrote: post #70

Earlier quoted context omitted.

You are getting downvoted, but I actually agree with you. Space travel is awesome, but so is living, and right now we are not living in a way that is sustainable over the short term. Space travel is, for me, an anachronistic hold-over from people who grew up with Heinlein, Asimov, etc., but is not something that is realistic given the environmental situation. Realistically, any vehicle that is dependent upon currentl…

To be fair space flight has some significant advantages from an environmental perspective. Earth observation satellites are essential for understanding how the atmosphere works and how the planet is changing. Also, the unique constraints of space have lead to the development of sustainable technology such as solar panels, fuel cells, and better water purification.

Who cares? Let's feed the poor first and worry about bigger stuff later. Reminds me of a story about a letter written by Sister Mary Jucunda from Zambia to Dr. Ernst Stuhlinger, then-associate director of science at NASA's Marshall Space Flight Center. (http://www.meaus.com/whyExplore.html)

Re: SpaceshipTwo crashes shortly after Mojave test flight

#175

Post by melling »

seanflyon wrote: post #103
melling wrote: post #65

Earlier quoted context omitted.

I didn't say ban manned space flight. We keep trying to restart our space program by sending people to Mars. I think we should start a more extensive national unmanned space program. For example, if the Hubble, or its replacement, needs to be fixed, we should have an unmanned answer, for instance. We should start building on Mars without humans. If our machines can't do that yet, then we should invest in them until t…

Are you suggesting we send several generations of robots to Mars first? That's a great idea and exactly what we have been doing for decades.

Yeah, didn't we land something there a decade ago? And the decade before that?

Re: SpaceshipTwo crashes shortly after Mojave test flight

#176

Post by jacquesm »

marze wrote: post #69
mixmax wrote: post #23

What this weeks events show us is that space travel is hard. Really hard. Most systems operate in extreme conditions, sometimes bordering on the improbable. Thousands, sometimes millions of horsepower in an engine smaller than a car, cryogenic liquids at -200 degrees celsius cooling a nozzle that is 3000 degrees celsius 5 millimeters away, heatshields designed to absorb obscene amounts of heat, the list just goes on…

Some say this is an "inevitable" result of pushing boundaries. No. This is the result of a poorly managed program. What they are doing is much easier than the Apollo program, which was well managed and had no in-flight failures that resulted in loss of life, while accomplishing an infinitely harder task. This is a tragedy, obviously. But the program is about six years behind schedule, been going for 10 years. The mos…

> Seeing only the first paragraph, I already know that some rubber in the hybrid engine detached blocking the nozzle and causing the whole engine to explode.

Let's hope they won't ask you to run the inevitable investigation then.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#177

Post by jacquesm »

CamperBob2 wrote: post #125
cstross wrote: post #111

Earlier quoted context omitted.

Actually, it could happen with chemical rockets -- if we abandon the idea of sending canned monkeys beyond the atmosphere. We can afford to send up a couple of hundred tons of prokaryotic spores every year until the cows come home, with solar sails to get their packages up above solar escape velocity. Over a few decades or centuries that's a lot of unicellular organisms to scatter on the direction of exoplanets; we c…

Ethically speaking, sending non-sentient foreign organisms to an unknown planet that might already be inhabited falls somewhere between spamming and attempted genocide. No, thanks. I prefer to believe that this task is what our intelligence is for .

For all we know we're only returning the favor.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#178

Post by Florin_Andrei »

jcrites wrote: post #50
mixmax wrote: post #23

What this weeks events show us is that space travel is hard. Really hard. Most systems operate in extreme conditions, sometimes bordering on the improbable. Thousands, sometimes millions of horsepower in an engine smaller than a car, cryogenic liquids at -200 degrees celsius cooling a nozzle that is 3000 degrees celsius 5 millimeters away, heatshields designed to absorb obscene amounts of heat, the list just goes on…

> Most systems operate in extreme conditions, sometimes bordering on the improbable. Indeed. Your statement reminds me of an insightful engineering article, "How Complex Systems Fail": http://www.ctlab.org/documents/How%20Complex%20Systems%20Fai... . A few relevant observations from the article that resonate with me: > 1) Complex systems are intrinsically hazardous systems. > 4) Complex systems contain changing mixtu…

Well, a rocket is a thing that:

1. contains a lot of energy

2. releases a considerable stream of energy at a controlled, steady rate

3. does that in a small system, while flying through the air.

It's a lot easier if you drop one requirement:

1 + 2 = coal-based power plant

1 + 3 = bomb

2 (sort of) + 3 = conventional airplane

All of the above have been done reliably. It's only when you put together all three conditions that you get a rocket, and that's when things get really, really difficult.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#179

Post by ericd »

slg wrote: post #32
JoeAltmaier wrote: post #21

Earlier quoted context omitted.

Its sad, sure. Sorry for their loss. But people take far greater risks for far less reason. Monster Truck rallys. Motorcycle racing. Skiing. We don't change national priorities every time somebody dies at those activities. SO lets keep it in perspective, and salute the brave folks who are trying to expand human boundaries.

Those aren't really fair comparisons as they are several orders of magnitudes less dangerous than space flight. My quick estimates say that roughly 1-3% of people who try to get to space die during some point of the journey. Some quick Googling put the fatality rate for skiing at roughly .00002%. If 1% of people who tried skiing died, you could bet there would be national discussions about it.

Summiting Everest, then? At some point, it was >10% mortality, yet people still did it, and it was considered acceptable, given that it was people doing it voluntarily. I believe that it's now in the ~1-3% mortality range.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#180

Post by danmaz74 »

crikli wrote: post #135
kashkhan wrote: post #109

Earlier quoted context omitted.

there's no need not in this day and age to have test pilots. If they use computers, they can debug the engine in flight conditions by running maybe ten times as many test flights. Delays of months between flights are dangerous. Until you have a 1000-10,000 flights to build up operational data and envelope, this is a death trap causing unnecessary deaths.

The first statement implies that computer testing is so good now that an aircraft can be tested so thoroughly that the maiden voyage of an aircraft could safely also be its first "for real" mission. It is true that computer models have definitely reduced the risks for test pilots by helping to define a much greater percentage of the performance envelope of a given system without the need for test flights. When a pilo…

I think he meant real-life test, but with the pilot working remotely and not sitting on board.
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