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.