SpaceshipTwo crashes shortly after Mojave test flight • Hacker News Board

Re: SpaceshipTwo crashes shortly after Mojave test flight

#21

Post by JoeAltmaier » Fri, Oct 31, 2014, 6:58 PM UTC

melling wrote: post #19

arjn wrote: post #11

Earlier quoted context omitted.

Totall agree. These people are the modern day seafarers. Heading out into unknown waters.

Someone dying is devastating. Trying to conquer space a handful of people at a time is the slow and dangerous way of accomplishing this task. We should be building machines to explore the solar system. This can be done for a fraction of the cost, time, and it will allow him to allow us to iterate quickly. In 100 years, more humans will live off earth if we iterate with machines, etc now than if we move slowly trying…

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.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#22

Post by nawitus » Fri, Oct 31, 2014, 7:04 PM UTC

JanSolo wrote: post #18

This is very bad. Not just for the family and friends of the poor guy who died, but for commercial manned spaceflight in general. SpaceshipTwo is considered the 'simplest' and 'safest' of all the upcoming manned commercial vehicle. It has many features that should help keep it reliable. For example, instead of a real liquid rocket engine, it uses a hybrid engine; it has almost no moving parts apart from a valve or tw…

It's been reported that it "exploded in mid-air", and two parachutes were deployed, so the cause probably was not the wing-feathering system.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#23

Post by mixmax » Fri, Oct 31, 2014, 7:04 PM UTC

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 and on.

Most people don't realize how hard this is. The physics, the engineering, the design.

Yet we have made great strides, especially over the last few years, and Virgin Galactic is a part of this. There is a new era of cheap spaceflight on the horizon, driven forward by fearless men and women that want to go to space no matter what the cost.

This is commendable, and is what drives the human race forward. Without these fearless men we wouldn't have gone to the moon. We wouldn't have explored the depths of the ocean. We wouldn't have flown the skies.

Today it appears we lost one of these fearless men, but he now rests in peace assured that others will take his place, that he was not alone in his longing to drive mankind forwards into the unknown, that his dreams live on to inspire others.

We have conquered the skies, and we will move on. Eventually we will conquer space and make it accessible to all mankind. A fearless man has given his life to allow us to some day leave the cradle that is mother Earth.

His ultimate sacrifice won't be in vain.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#24

Post by cfreeman » Fri, Oct 31, 2014, 7:09 PM UTC

JanSolo wrote: post #18

This is very bad. Not just for the family and friends of the poor guy who died, but for commercial manned spaceflight in general. SpaceshipTwo is considered the 'simplest' and 'safest' of all the upcoming manned commercial vehicle. It has many features that should help keep it reliable. For example, instead of a real liquid rocket engine, it uses a hybrid engine; it has almost no moving parts apart from a valve or tw…

They just switched to a new liquid powered engine because their hybrid engine was not powerful enough. This was the first powered test flight with their new engine, and given the information so far it sounds like it exploded in-flight. Very, very, tragic.

edit: I'm wrong. They simply switched to a new type of fuel for their hybrid engine.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#25

Post by [deleted] » Fri, Oct 31, 2014, 7:09 PM UTC

nawitus wrote: post #22

JanSolo wrote: post #18

This is very bad. Not just for the family and friends of the poor guy who died, but for commercial manned spaceflight in general. SpaceshipTwo is considered the 'simplest' and 'safest' of all the upcoming manned commercial vehicle. It has many features that should help keep it reliable. For example, instead of a real liquid rocket engine, it uses a hybrid engine; it has almost no moving parts apart from a valve or tw…

It's been reported that it "exploded in mid-air", and two parachutes were deployed, so the cause probably was not the wing-feathering system.

[deleted]

Re: SpaceshipTwo crashes shortly after Mojave test flight

#26

Post by JanSolo » Fri, Oct 31, 2014, 7:12 PM UTC

nawitus wrote: post #22

JanSolo wrote: post #18

This is very bad. Not just for the family and friends of the poor guy who died, but for commercial manned spaceflight in general. SpaceshipTwo is considered the 'simplest' and 'safest' of all the upcoming manned commercial vehicle. It has many features that should help keep it reliable. For example, instead of a real liquid rocket engine, it uses a hybrid engine; it has almost no moving parts apart from a valve or tw…

It's been reported that it "exploded in mid-air", and two parachutes were deployed, so the cause probably was not the wing-feathering system.

Yes, looking at the twitter feed, multiple sources state that it blew up. This means that either the tank (which takes up the whole rear half of the vehicle) failed catastrophically (unlikely; CF-wrapped tanks tend to develop hairline cracks which slowly leak out) OR the engine exploded.

What's interesting is that the SS2 engine fuel was swapped out very recently for a new thermoplastic polyamide solid fuel for better performace. Maybe this new fuel was not tested as well as it should have been?

Re: SpaceshipTwo crashes shortly after Mojave test flight

#27

Post by thisGuysAccount » Fri, Oct 31, 2014, 7:15 PM UTC

JanSolo wrote: post #26

nawitus wrote: post #22

Earlier quoted context omitted.

It's been reported that it "exploded in mid-air", and two parachutes were deployed, so the cause probably was not the wing-feathering system.

Yes, looking at the twitter feed, multiple sources state that it blew up. This means that either the tank (which takes up the whole rear half of the vehicle) failed catastrophically (unlikely; CF-wrapped tanks tend to develop hairline cracks which slowly leak out) OR the engine exploded. What's interesting is that the SS2 engine fuel was swapped out very recently for a new thermoplastic polyamide solid fuel for bette…

static wick failure, minor fuel leak, big bang.

That said, I really have no clue about how these things work. That's just one scenario I could see leading to a midair explosion.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#28

Post by ggreer » Fri, Oct 31, 2014, 7:16 PM UTC

JanSolo wrote: post #18

This is very bad. Not just for the family and friends of the poor guy who died, but for commercial manned spaceflight in general. SpaceshipTwo is considered the 'simplest' and 'safest' of all the upcoming manned commercial vehicle. It has many features that should help keep it reliable. For example, instead of a real liquid rocket engine, it uses a hybrid engine; it has almost no moving parts apart from a valve or tw…

The engine has been the bane of SS2. The original rubber/N2O design was problematic enough that Virgin switched from rubber to a plastic. Apparently this was the first powered flight to use the new fuel.

While the design lacks complicated turbopumps and cryogenic fuels, it does have one drawback: the N2O is contained in a pressure vessel. If that tank is damaged while still full (or close to), bad things can happen.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#29

Post by melling » Fri, Oct 31, 2014, 7:16 PM UTC

JoeAltmaier wrote: post #21

melling wrote: post #19

Earlier quoted context omitted.

Someone dying is devastating. Trying to conquer space a handful of people at a time is the slow and dangerous way of accomplishing this task. We should be building machines to explore the solar system. This can be done for a fraction of the cost, time, and it will allow him to allow us to iterate quickly. In 100 years, more humans will live off earth if we iterate with machines, etc now than if we move slowly trying…

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.

I think you're overlooking the fact that Virgin Galactic isn't a national priority, it's a commercial venture. And it'll probably take years of testing to convince many people to take their flight, assuming they want to spend the money.

The ability of the United States to send people to space ended because of the last shuttle accident. So, yes, people dying did affect our national resolve. I think if you do the math, flying in the space shuttle was more dangerous. There were only 135 flights? We lost $3.5 billion of hardware and 14 lives in 2 accidents.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#30

Post by atlantic » Fri, Oct 31, 2014, 7:17 PM UTC

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…

> This is commendable, and is what drives the human race forward. Without these fearless men we wouldn't have gone to the moon. We wouldn't have explored the depths of the ocean. We wouldn't have flown the skies.

That's one way of looking at the matter. Another is that without this untrammelled technological evolution (I hesitate to use the word "progress") we wouldn't be living through the greatest mass extinction event of the last few of million years. A lot of this effort could go instead into finding a better cohabitation between humans and the other species with whom we supposedly share the planet.