This is a tragedy, obviously. But the program is about six years behind schedule, been going for 10 years. 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. I know first hand that groups with such engine expertise have approached Virgin and been turned down.

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. The pilots should have refused to fly until Virgin had 10 consecutive motor qualification tests at full duration, not ride on a ship with a half-baked motor that has seen constant modifications during the last year.

In the software development world, a "death march" in a program behind schedule does not result in loss of actual life, not so in manned spaceflight.

The flaws in Apollo One were so severe the three crew died on the launchpad. Describing that tragedy as "no in-flight deaths" is accurate but misses some important information.

http://en.wikipedia.org/wiki/Apollo_1

http://en.wikipedia.org/wiki/Lunar_Landing_Research_Vehicle

(And I see another test pilot, Joe Algranti, also had a very close call flying a second-generation LLTV -- ejecting 0.6 seconds before it crashed!)

NASA came very close to losing more astronauts during mission prep for Apollo, in addition to the Apollo 1 crew. (Even if we leave aside the four astronauts killed in T-38 crashes in the 1960s.)

The computer kept flying the machine despite the interrupts and reboots due to the radar switch that Buzz had left on. It was really marvelously designed to be able to keep on executing its highest priority tasks.

The reason for the (semi) manual control was that the designated landing spot was a boulder field. The computer kept on operating the throttle.

Source: Apollo 11 Lunar Surface Journal.

The cargo ship was expected to and successfully docked with the ISS later in the day.[2]

[1] Russia Launches ISS Cargo After US Craft Explodes

http://www.voanews.com/content/russia-launches-iss-cargo-mis...

Russian supply ship poised for launch Wednesday

http://spaceflightnow.com/2014/10/28/russian-supply-ship-poi...

[2] Russian Progress M-25M docks with the ISS

http://www.nasaspaceflight.com/2014/10/russian-progress-iss-...

To put it in perspective, Apollo flew on a rocket with five engines producing 1,500,000 lbf thrust each, on the first stage alone. By contrast, the Virgin motor produces 60,000 lbf thrust for 70 seconds.

The Apollo program had a safety culture configured so that if anyone identified a safety issue, they became responsible for the problem and responsible to sign off that it was corrected.

http://en.wikipedia.org/wiki/Budget_of_NASA#Cost_of_Apollo_p...

Edit: It's also worth noting that the same entity that ran the Apollo missions currently has no way of putting people into space, and the last system they had also looked like a plane... and had problems with exploding and killing people.

That's funny, because you were the one who compared them first.

Although the Virgin 60,000 lbf rocket is small by the standards of Apollo, it is still an extremely challenging problem. There are no problem-free or inherently safe options, so safety needs to be engineered in from the bottom up carefully and competently. Otherwise, failures like this will not happen just once.

The engineers involved would do well to study the Apollo program and other successful complex engineering efforts such as nuclear reactors, as well as the counter examples of the two space shuttle that were lost due to management putting schedule ahead of safety.

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 what you know is wrong, they weren't using rubber.

I think a good case can be made that they didn't do enough ground testing, but your post mixing disdain and falsity doesn't advance that case.

"Liquid/liquid engines, by any measure, are orders of magnitude more stable."

What do you mean by stable?

A reason to go with hybrids, at least on paper, is that they are mechanically simple but throttlable, hopefully combining the simplicity of a solid booster with the ability to throttle and shutdown of a liquid.

Of course, much of that also applies to blowdown liquid systems, and I personally find a blowdown methane/lox system particularly compelling. I figure Virgin wanted to avoid cryogens, though.

I think Paul McCartney was about 23 years old when the engines powering that Antares launch vehicle were fabricated in Russia in their race against the Americans to the moon. An antique liquid/liquid vs an inadequately qualified hybrid: no winners.

I'm not sure what constitutes adequate qualification, though. Both engines were ground tested at least some. And in Virgin's case, this flight was one of tests.

http://en.wikipedia.org/wiki/NK-33 says the AJ-26 engines are from the 1960s and 1970s.

This you believe so strongly because a news story stated it?

Wait for the accident report. It will say "rubber".

http://m.aviationweek.com/space/new-fuel-boost-spaceshiptwo

Problems like these are almost always the result of management pushing things faster than the engineering progress warrants.

"Problems like these are almost always the result of management pushing things faster than the engineering progress warrants."

Coincidentally, we were talking about such an instance today at work, the Conestoga 1620. As relayed to me, the "low frequency noise" mentioned in the wikipedia post was a low frequency structural mode that was missed because management didn't want to pay for a high enough fidelity finite element analysis.

https://en.wikipedia.org/wiki/Conestoga_%28rocket%29

“This was a new fuel formulation that had been proven and tested on the ground many times,” Mickey said in a press conference.

http://spaceflightnow.com/2014/10/31/virgin-galactics-spaces...

I have heard of one long duration test on the plastic fuel reported by the "Virgin watchers" in Mojave, so unless they are doing long duration tests somewhere else it doesn't seem like much. Rocket engine testing is extremely noisy so long duration tests are quite noticeable.

Some of the boundaries that are being pushed are how much oversight, how meticulous, etc you have to be. In other words, how well you have to manage the program, how tight a ship you keep.

Keeping a tight ship raises costs, and isn't the big emphasis of all this privatized space travel on reducing costs?

Speaking of which, your username was coined by a traditional drummer/singer friend of mine. Do you know her?

In case you aren't trolling me, my snark was a reference to http://knowyourmeme.com/memes/in-this-moment-i-am-euphoric

I don't know your friend, but my username is pretty stupid, so if she wants to take credit for it she's 100% welcome.

I don't think you're that simple, I think you're just trying to be derisive.

In case you're not :

Regardless of the effort involved, a value must be paid in order to form a new technology or model.

We, the people who strive to create, choose in what way we would like to pay this value. We can choose to pay for progress through time, or pay for progress through means of trial and error.

While not mutually exclusive, one methodology tends to detract from the other while serving the same purpose : the pursuit of a novel model.

The methods of payment are not mutually exclusive, the ethos behind the choice to prioritize one over the other typically (but not necessarily) is.

An off-topic example I can think of would be the drive behind early Russian aviation/aerospace versus the drive behind early United States aviation/aerospace.

Different priorities got both parties to a comparable level of technology regardless of the differing means used to get there. Free market competition rushed much of early Russian aviation and made wide use of anecdotal evidences and test piloting and created leading edge machines because of it, whereas government subsidy and large cash flows drove the US to stay on top using theory and finances instead of prioritizing the happiness of pilots and fulfilling 'stick-feel'.

(before anyone mentions it, both parties did the same stuff, they just differed in prioritization)

Both parties created fantastic machines. One paid in blood, the other in time for such achievements.

I didn't say it's a nice quote. I said it's a nice sounding quote, and I did mean that in the LessWrong sense of "false sagacity." In terms of tone, you sound a bit like a troll to me.

"Blood and treasure," is a phrase used to refer to money and lives/health of personnel.

And no, I was not trolling you. Please read my previous comment as factual, with very subtle nuance in the 1st sentence.

The private sector isn't somehow just better at stuff. It has different motives and different priorities, and makes different compromises.

Is it? Is there evidence that the private sector is consistently more accident prone that public entities when doing similar activities?

Does this same concern apply to plastic-based fuel? It does seem like a terrible idea to have people in the rocket the first time you try a new fuel mixture.

"During the nine months since the previous rocket-powered test in January, Virgin Galactic switched SpaceShipTwo's fuel mixture from a rubber-based compound to a plastic-based mix — in hopes that the new formulation would boost the hybrid rocket engine's performance."

http://en.wikipedia.org/wiki/Hard_start

Another - nitrous oxide can become explosive in gaseous phase. If enough of it became gas, the oxidizer tank may have exploded.

There are also inherent instabilities of hybrids - higher pressure accelerates the burn, which increases pressure, which...

We'll know more after they finish the investigation.

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

Can I ask how? What is in there that tells you that?

You've got a hybrid motor, it's flown a number of times. You have a program that has been going for years but still hasn't got the motor design finalized due to unknown (to us) problems. Failure modes that could destroy the vehicle include things like pressurized oxidizer tank failure, burn-through of the nozzle, burn-through of the main combustion pressure vessel, blocking of the nozzle by unburned solid fuel chunks causing over-pressure failure, and the like. The last one seems most likely, since it's likelihood is modified by modifications to the fuel (which is what they are probably changing, as opposed to the nitrous system or structure or nozzle).

Obviously no one knows for sure yet.

I'd love to see civilian spaceflight become a reality, so this is an unfortunate setback. I hope Virgin will be able to take the time to get it right. I hope they will look back at this accident the same way the Apollo program viewed the Apollo 1 fire, as a much needed chance to fix a lot of potential issues that needed fixing that were thought to have contributed in a fundamental way to the lack of subsequent in-flight failures.

I agree that, for all we know, it was the catastrophic failure of a rocket engine that was not tested enough that killed a pilot and that they should have tested the engine for much longer than they appear to have.

I imagine they switched to this design because it's supposed to be a better one.

"During the nine months since the previous rocket-powered test in January, Virgin Galactic switched SpaceShipTwo's fuel mixture from a rubber-based compound to a plastic-based mix"

https://en.wikipedia.org/wiki/List_of_software_bugs

- radiation therapy machine kills 5 - clock drift in Patriot system caused 28 killed - Chinook helicopter killed 29 due to bug in engine control - Toyota's electronic throttle control system caused dozens of fatalities

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.

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 pilot steps into an untested craft for the first time, the "unknown" area of the envelope is better quantified; in different words, we have a better idea of how much of the performance envelope is unclear.

Yet that unknown area still exists and has to be discovered by actual human test pilots because as good as computerized testing is there still isn't 100% coverage.

(I'm a pilot and have dealt with experimental aircraft. Not on the level of this project, of course, where the envelopes of technology are being pushed, but on the level of small private aircraft where the technology is in many cases half a century old, well understood, debugged, and still has to be tested. By a human.)

For testing the engine which in this case is throttleable and has time constants greater than hundreds of milliseconds the time lag from not having a pilot onboard is acceptable.

For flying qualities again the plane is large enough to be slow enough that remote pilot timelag is not significant.

There is no part of the envelope of this vehicle where you need a pilot onboard. Most of the development here can be done without pilot onboard. Space has been done from unmanned vehicles since the beginning and what they are doing is only barely rocket science.

Putting a pair of pilots in a vehicle with a non-flight-tested rocket engine is just irresponsible.

I like Rutan's company. But what they are doing on this program smacks of amateurism. They got engineers killed on the ground and now pilots killed and injured in flight. Both of which were completely preventable by some basic range and flight safety measures.

It looks like they are cutting corners by doing too much too soon because of management pressures to cut delays. And people are paying the ultimate price for their hubris.

At least one shuttle flight would have been lost if the crew didn't fly manually to correct for a malfunction. STS-4 PIO'd on landing and would have crashed if auto-stabilization wasn't overridden by the pilot.

Good point. What does the FAA say about unmanned rocket powered flight tests?

1:http://en.wikipedia.org/wiki/Grasshopper_(rocket)#Flight_tes... 2: http://en.wikipedia.org/wiki/Falcon_9#Launch_history

In fact, you don't even know that rubber in the hybrid engine blocked the nozzle. You can't know that - you aren't part of the investigating team. And they don't even know yet.

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 mixtures of failures latent within them.

> 5) Complex systems run in degraded mode.

> A corollary to the preceding point is that complex systems run as broken systems. The system continues to function because it contains so many redundancies and because people can make it function, despite the presence of many flaws. After accident reviews nearly always note that the system has a history of prior ‘proto-accidents’ that nearly generated catastrophe.

> 17) People continuously create safety.

> Failure free operations are the result of activities of people who work to keep the system within the boundaries of tolerable performance. These activities are, for the most part, part of normal operations and superficially straightforward. But because system operations are never trouble free, human practitioner adaptations to changing conditions actually create safety from moment to moment.

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.

At the start "n" is small 1 flight, 5 flights etc. It's pretty much a given that there will be failures it's just a matter of when and how critical a failure. The failures would be loaded toward happening early on and then fixed so that one particular failure shouldn't happen again. Something else might of course.

As an aside this is similar to why large companies have really long involved legal contracts. They are large enoug,h and have run into enough problems, (or employ attorneys who have) that they've seen it all and done it all and know what they need to do to protect themselves because of the statistical chance that in their large operation a particular problem will appear.

In other words more likely that with a footprint as large as McDonalds there will be a customer that get's scalded by coffee and files a lawsuit than the local coffee shop on main street USA. More customers means more chances of some outlier even happening.

If you're a small company you generally get to deal with each and every case, and do risk assessment up front on an individual basis. When you're big you're doing enough jobs to standardise those assessments (getting the economies of scale going), processes, and any resulting contracts. The problems get going when the supporting bureaucracy has lost track with reality and becomes a self perpetuating beast, but at least in the early stages it should be beneficial.

That's really the key point actually. Things become self perpetuating without anyone even questioning if they are still even necessary.

That said most people don't read contracts (at least most consumers) so in a sense and in certain situations it pays to stuff as many things in there as possible.

What's interesting is how many risky situations you enter into with potential liability where you don't sign a contract.

For example nobody signs a contract to eat a meal at a restaurant. You don't sign away your right to sue if the food is bad or if the meal isn't delivered on time. The car company that sells you a car doesn't require you to sign a contract with them the dealer of course has a sales contract which is different. Car company is big enough to not really have to go that route. They know they don't need a contract to protect against the little things and with a big thing it doesn't matter.

Otoh an electrician just quoted a job to me for under $800. And he sends me this long involved contract (that no doubt he copied from another electrician) which really isn't necessary for this type of job.

I remember when a developer I hired to do work started many years ago. It was a $60k job. Long and involved contract. Ended up signing it (needed the work had no choice). Well we are still doing business 12 years later. But it evolved into a handshake. Nothing in the contract says he has to take my call at 11:00pm on a Saturday night but last weekend he did just that. He and his team finished the repair by Monday morning. I told him to take his wife and family to dinner and we'd pay the bill. Not required but I was really appreciative of the effort. He thanked me and told me it was his job to make sure things were working but he appreciated very much.

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.

Our resources would be better spent elsewhere. I know that this opinion is anathema on a tech-heavy site such as this one, but I must nevertheless express my respectful disagreement. It would be far, far more productive for the species to dedicate resources towards CO2 and CH4 reduction in the lower atmosphere.

Space travel is fundamental to the human species living sustainably in the long term. Correcting greenhouse gasses doesn't help us if the next day we find a planet-killer asteroid is a few weeks away.

In this regard, the comment about CO2 is actually much more pertinent than it seems at first. If we manage to screw up the climate in this century (which seems very likely these days), inundating every coastal cities in the world, "sustainable space colony" will have to wait a bit longer. Much longer. If you're worried that an asteroid might hit us 500 years from now, you might want to rethink your priority.

Advancing chemical rockets now is important, but compared to the scale of space colony, it feels somewhat like producing better vacuum tubes to make sure (say) the US is the first to create strong AI. Any sane 50s US leader would have understood that "trying not to have a nuclear war with Soviet" is a much more important goal anyway: you can't fund AI research if your country is a radioactive wasteland.

We went from not flying anything heavier than air to going to the Moon in 66 years. If we really really wanted to, we could go to Mars in thirty. This is a problem of priorities, not technologies (although the technological problems are real, they are not insurmountable).

CO2 is a direct and immediate threat.

Unless the lead time is 50-100 years, years might as well be tomorrow, it's going to kill us all either way. Even that might be stretching it.

> Humans as a species will survive CO2

Maybe, personally I believe humans will cause their own extinction. I'm just not sure yet if we're going to take all life with us or not. Dealing with CO2 is a toss up between making the planet uninhabitable or completely inhospitable to life.

So... what, we just halt development of all vehicles, globally, period? Bye-bye trains, planes, cars, bicycles, and buses?

You can't develop the future of transportation or the future of propulsion systems if you literally shut down global commerce.

Besides, an airplane (for example) is not wedded to the engine. Developments in prop planes carried over directly to jet planes, once the jet engine matured. Any future propulsion system that can replace jet engines will probably not be hard to work into many plane designs of the day.

Better to make incremental progress on poverty, without constraining the innovators to work on problems that don't interest them, or that seem even more intractable than e.g. space travel or AI.

Those same < 10 000 people probably doesn't know nor have the ability to fix all the problems on Earth, but they might be able to get to Mars.

Parent: See that little blue dot in the night sky? That’s Earth.

Child: What is Earth?

Parent: Earth was the planet of our ancestors, before people came to Mars.

Child: Who lives on Earth now?

Parent: Nobody. It’s a dead planet. The actions of rich, selfish people destroyed it.

Child: How did the rich, selfish people destroy Earth?

Parent: They burned it up as fuel, getting to Mars.

That proverbial man who plants trees knowing he will never sit in their shade is proverbial for a reason.. it's an amazing and heartwarming little saying because it's a contrast to how we generally behave, as individuals as well as organizations and masses. We learn from repeated catastrophe.. sometimes, maybe. But this problem is not one we can have a lot of attempts at solving. Right now we are still moving into the wrong direction, and probably even accelerating.. sure, hitting a wall can make people change their direction, but not if it breaks their neck, so to speak.

I'm not enormously optimistic. I'm just saying that compared to interstellar travel, avoiding fossil fuels seems like a fairly small problem.

The biggest lever we've got right now is computation, so yeah maybe it would be more efficient to develop AI / IA first and then mass space travel, but we can't be sure.

Also, fundamentally we can accept a few billion deaths. That sounds and is grotesque, but it wouldn't be the end of humanity. I don't see how climate change kills us all in the next 100-500 years.

This is a false dilemma. We have 7+ billion people on the planet. There is most certainly a significant amount of effort going towards the future you mentioned. They are not mutually exclusive (and are, most likely, going to be a product of each other)

At least with the mass extinction there are prospects for fixing the problem.

I wonder what the carbon footprint of space tourism is, and will be if it becomes cheaper and more popular? I feel guilty flying on a plane.

Let's go see the universe, and take life along with us.

Meanwhile, all of the derivative research (effects of zero gravity, life support systems, shielding, re-entry, etc) stagnates. And I guess we should dismantle our satellite systems as well, since they require rockets to achieve orbit.

Maybe we should ban all cars while we're at it, since they pollute our environment. We should shut down the evil factories, too, so no electric cars, either.

Yup, we can just sit in a circle, singing kumbayah while we wait for that miraculous perfect power source that someone else will develop for us. Then, and only THEN, can we continue with "progress".

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 can hope that in a few million years one or another strikes edible dirt and begins to reproduce.

This is, however, not as mythically resonant as "space: the final frontier" ...

No, thanks. I prefer to believe that this task is what our intelligence is for.

Bacterial colonization is a useful argument for interrogating the "we must colonize spaaaace!" folks' intentions. I mean, why exactly must we colonize space?

"Before the sun leaves the main sequence of the Hertzsprung-Russell diagram/the Earth is hit by a comet or irradiated by a GRB" is a meaningless argument. These events happen on a time frame of hundreds to thousands of megayears; while the mean life expectancy of a mammalian species is on the order of one to ten MYa, and for a hominid species like us, it's well under one MYa. These arguments don't hold water. Furthermore, we coevolved with our biosphere and we're really badly adapted to existence without a large subset of it: calling for human space colonization is implicitly a call for terraforming/transporting a viable terrestrial biosphere to other worlds. Which brings us neatly back to bacterial colonization, because that's part of the package deal.

While I can't refute the quasi-religious imperative implicit behind the rhetoric for space colonization, I wish its proponents would recognize that it's essentially a faith-based ideology!

The Antarctic being a barren wasteland makes it an attractive breeding ground for penguins precisely because it's so inhospitable to anything alive, penguins included. As long as penguins suck less at living in a barren wasteland than their predators it's a net benefit for them to be there, despite the hardships of the environment.

If we assume there is a group of humans that feel existentially threatened by other humans so much that odds of surviving in an irradiated subterranean Mars colony beat the odds of being exterminated here on Earth, it would be a perfectly rational choice for them to try and move somewhere out of reach.

There are lots of potential scenarios why such groups might come into existence, and not all of them involve outright genocide. For example, a group could form just as a result of concerned citizens wanting to go to some place very, very remote once kids start playing Pokemon with their newfangled RNA synthesizers.

No, we're not going to move a billion or two people with them, but that's not what we need to make humanity multi-planet.

It might be hard to argue that our industrial pillage of the planet is solely a result of exploration. Anything weaker than that and I think you have the tougher position.

More recently Oil is currently driving a lot of exploration into the oceans and other remote regions.

PS: Not that I think we should all just stay home, but whitewashing history is stupid.

Absolute zero is -273 °C.

Wikipedia lists: 19 Test Pilots 18 Astronauts in spaceflight 11 Astronauts in training

The death tolls for social progress are vastly greater.

These people choose to dedicate and risk their lives drive us forward.

We mostly still haven't! I think ocean exploration is pretty exciting too.

You are all prey to the "religion of progress".

Your dogma is that space travel is not only possible, but a given, something the universe has put somewhere for us to find and make ours.

Except that, basic hard laws such as the speed of light, the laws of thermodynamics, etc. say NO. And it's only your religious thinking that allows you to handwave all that with a "we always find a way".

For all we know, in this universe it may be impossible to bypass or even bend those laws. Yet, you're betting the future of the species on old Star Trek fantasies.

As you said, the conditions and difficulty for modern space travel are in the extreme and pushing all of our sciences to their limits. And for what? just to get to... the moon. I don't want to scare you, but if that seems far to you, see how much bigger the distance to anything else in the solar system is, nevermind anything outside it.

This is not true. For travel within the solar system the speed of light is no more than a nuisance delaying communication. The laws of thermodynamics don't stop space travel. No one is saying "we always find a way" to do the impossible. We are saying "we always find a way" to do that thing that we already know how to do and have demonstrated lots of times, only this time we need to make it cheaper.

b) We just need to make it cheaper? how, exactly, are you going to get up there except by burning obscene quantities of solid (fossil) fuel, as we do now?

That's where the thermodynamics things comes in play: you have to pay the energy cost, there's no elegant "oh, we're just going to fold space" or some such bs. And fossil fuels are finite by definition, need I remind you.

It's not "we just need to make it cheaper". It's coming up with new breakthroughs in physics that no one can assure even exist.

b) You have to pay the energy cost but that is not the hard part. Fossil fuels are finite, but we don't need to use fossil fuels and even if we did setting up a civilization on mars would take a tiny portion of earth's fossil fuels. We are not going to run out of hydrogen as long as we have the energy to split water and plenty of energy hits the earth in the form of sunlight every day, not to mention fission or fusion.

So no, the laws of thermodynamics are not the problem. We "just" need to make it cheaper.

[0] News report: http://www.theguardian.com/science/2014/oct/31/spaceshiptwo-...