SpaceShipOne Flight Not as Perfect as it Seemed

ArbiterOne writes "SpaceShipOne's flight wasn't as perfect as it seemed, according to Burt Rutan and New Scientist. Apparently, at one point in the descent, the pilot completely lost attitude control. According to him, "If that had happened earlier, I would never have made it and you all would be looking sad right now." Could this pose some problems for the X-Prize contender?"

Comments

Still a great flight

[PFactor]

I don't see anyone doing any better than they did (yet).

It's perfectly normal

[JosKarith]

Build...test...improve...retest...etc
It's how aeronautical design's been done for decades. I very much doubt this'll be a major setback for them.

This is why more people didnt go

[PktLoss]

A few of my friends were very surprised that this run wouldn't count at all for the X-Prize, since it didn't have enough people or weight to replace them.

This is exactly why, it was a test run, things can, and did (though fortunatly not bad enough to have resulted in loss of life) go wrong.

I think this was exactly the right way for them to have approached this, go up with as little extra as possible, see what goes well and what doesn't, and make revisions based on that. Though an extra 300lbs might not have mattered much with this particular problem, in other cases it could have turned a small problem into a disaster.

Re:This is why more people didnt go

[stanmann]

Well, because TECHNICALLY he entered space. He IS an Astronaut.

100km is defined as space... and its not a big deal that its being done, the big deal is that he did it for cheap.

If I get my wife Barely pregnant, barring complications she will nevertheless have a baby

if I barely hit you with a hand grenade, you will be just as dead.
if I barely hit your house with a nuclear weapon, you will still be dead.

the wright brothers barely went 100 meters, but it was powered flight.

Barely is the difference between hitting and missing.

Minor Issue + Space = Scary, but keep trying!

[Ayandia]

For spaceflight it seems to take fewer imperfections to kill you. For a first run mostly perfect is fantastic...especially since the not perfect parts didn't involve dying.

The flight was a success, the pilot survived, and the ship wasn't damaged? Good job guys! Don't get lazy!

Accept the risk

[mratitude]

As a society viewing the initial private sojourns into space we need to prepare for the risk these people will take and we need to prepare ourselves for the first casualties. Otherwise, when someone does die, we'll knee-jerk the issue to the point that someone will suggest "There ought to be a law...".

There's been quite enough of that already, thank you very much. Get ready for it, it's going to happen. Every pioneering effort accumulates causualties.

It should have been expected

[Jetson]

The article says that he lost attitude control at the end of the burn as the ship was leaving the atmosphere. What else would you expect, considering the primary attitude controls are atmospheric flight surfaces? Once the ailerons, elevators and rudders have no air to push agains you're pretty much stuck with gyros, attitude thrusters or a controllable main engine thrust nozzle. This craft had NONE of those, so It would be completely reasonable to expect it to tumble until the air friction had built up enough for the fins to reorient the aircraft along the motion vector.

Re:It should have been expected

[Thagg]

SpaceShipOne is fairly unique in that the horizontal tail surfaces are outside the span of the wings. It uses differential movement of these tail surfaces to control roll. At subsonic speeds the pilot controls the elevons at the back of these surfaces, through a fairly normal linkage, but as you get to supersonic speeds the aerodynamic forces become impossible for human strength to overcome. So, at high speeds the front half of the tail control surfaces are moved electrically to generate pitch and roll forces. Apparently one of these electric trim systems failed.

The Bell X-1 used a similar electric trim for pitch, to overcome instabilities going through Mach 1.

Because the elevons on SpaceShipOne control both pitch and roll, Melville was left with no control on two out of three axes at the end of his climb. I cannot imagine how this must have felt, but he recovered with astonishing speed -- and was playing around with floating M&M's a few seconds later. It's unclear to me just what kind of "backup system" he used to control the ship after the trim motor failure, perhaps it was the cold-gas thrusters.

SpaceShipOne depends on still being within the vestiges of the atmosphere for control while the rocket is firing, although the parent poster is correct, control will get sloppy toward the end of the burn as they get above 150,000 ft. The ship has the advantage that it is going very fast indeed at that point, so while there is not a lot of air up there, the forces is generates is more than you would expect.

I was surprised watching the launch that the exhaust plume did not change much during the flight from 50,000 ft to burnout -- I would have expected to see far more expansion as it left the atmosphere -- as you see during a MinuteMan launch, for example. This again points to the ship still being atmosphere of some significant (while small!) density at burnout.

That Mike Melville is one hell of a pilot, his skill and Burt Rutan's innovative feather recovery saved the day. Every previous manned exoatmospheric craft depended on flying an extremely precise attitude before and during re-entry. Failure to maintain this attitude led to the loss of an X-15 and the NF-104 as dramatically recounted in The Right Stuff. SpaceShipOne has no effective attitude control during re-entry, but feathering the wing put the ship into an extremely stable high-drag configuration. Once the ship was subsonic and the wing was folded back into its normal position, the manual control of the elevons was used to fly the ship to a perfect landing.

If you look at SpaceShipOne as it flew yesterday, there was significant work done in the tail booms after the previous flight and prior to this one -- the most obvious change is the installation of a few more camera portholes (presumably with cameras behind them). That's the first place I'd look for the cause of the trim failure.

The launch yesterday was great fun to attend, and I really do think that it will mark a profound change in our access to space.

Thad Beier

Indeed

[adequacy]

Maybe there is a valid reason why Nasa is so expensive after all.

Indeed! NASA never has accidents that kill people. Through the mass application of science and billions of taxpayer dollars, all risk has been eliminated from space travel. Carry on, sir.

Class act

[amightywind]

Credit Mike Melville and Burt Rutan for being so open about the problems they experienced. Remember, this is 1 day after the flight! Compare that with how NASA closed ranks and divulged Columbia information with an eye dropper for weeks after the disaster. The only statements made by the mission controllers were through their lawyers. The Russians and Chinese would never admit to problems at all. Burt Rutan is a genious, he puts his work on the line for all the world to see. Space Ship 1 is a class act all the way around.

minor setbacks and some carmack links :P

[FaerieBoy]

I've been following armadillo for some time, and though armadillo/carmack doesn't think armadillo is going to win the x-prize, carmack stated before that control systems/requiring a pilot could lead to major setbacks for Space Ship One and change the odds (back in august). And more recently he discussed his focus on control systems.

According to one article they had to run on backup systems, another said the pilot heard a loud BANG at one point (lost that link). Not happy stuff, clearly they moved too soon.

For me, i'm not all that interested in the higher cost version of scaled composites, Rutan IS a pioneer, but previous work has also been government related. Which is why I laugh at the whole notion of public/private. Don't get me wrong, govt funding/projects are a good thing. But im sick of the BS pretending that there's the government and there's private industry. They are interelated, and we would do well to discuss, and plan, that relationship and public funding of r&d. And dont get me started on healthcare.

Re:This isn't what I expected

[Coryoth]

I'm really impressed with the White Knight launching vehicle and the new rocket design but all the Spaceship One team have proven that given enough money, anyone can build a spaceship. We knew that already however.

Really? It seems to me that Scaled Composites have redefined "enough money" to be a hell of a lot lower than it used to be. So far they've spent about $20 million, which sounds like a lot, but let's put that into some perspective: That's less than the cost of a brand new 747. It's about 5% of the cost of a single shuttle launch. It's less than a 5th of what the Canadian government recently pissed away on cronyism in the recent sponsorship scandal. It's the amount of cash Peter Jackson is getting paid to direct King Kong. On the scale that these guys are operating $20 million is a piss in the bucket. It's more than you or I might happen to have lying around in spare change, but compared to the costs for standard everyday (non space going)performance aircraft it is unbelievably cheap.

Jedidiah.

Re:This says quite a bit about...

[at_kernel_99]

This says quite a bit about... ...the pilot's skill.

It does. Though I'm not sure what it says about his judgement. I certainly have the highest respect for Melville as a pilot - he's been testing for Burt for decades. However, when you look at the flight - he noticed control anomalies immediately after separating from White Knight, but chose to continue the flight - maybe he did indeed get very lucky. What caused the bang? What caused the control problems both early and late in the flight?

In flight training, my instructor called it 'get home-itis'. When you're close to home you're a lot more likely to press on in deteriorating circumstances than if you're still far from home. With the public & press invited to this launch, was there too much pressure on Melville to make the flight despite early signs of possible problems? I hate to second guess a professional of his caliber, but it feels like there was a lot of luck involved in this flight.