Sorry for not posting sooner, but my DSL connection's been flaky all morning.

I'm concerned about that roll we saw during ascent. I was very concerned when it seemed to be accelerating, but it looks like he got it under control after engine shutdown. I wouldn't fly again until I understood what caused that. I'm pretty sure that I wouldn't want to ride a vehicle that did that, though others' mileage may vary.

It was a little irritating to listen to John Pike on Fox. On the one hand, he actually did seem to be cheering them on, but he's out of date on current events. He told the Fox hosts that DaVinci was planning to fly in the next few days, when they've announced that they're delayed several weeks. It would be nice if media people could get some other names in their space rolodexes than John's.

Maybe more thoughts later.

[Update]

Bruce Hoult (in comments to this post thinks that it's being caused by swirl in the oxidizer flow of the engine. I doubt that. Brett Buck has a different, and more plausible to me (and more disturbing, if correct) diagnosis over at sci.space.policy:

...the problem appeared to be a coupling from yaw to roll - definitely had a significant yaw angle, and the effective dihedral is extraordinarily high with this design - a lot like the lifting bodies that had similar control issues. Maybe that resulted from a yaw thrust vector misalignment, maybe just plain old roll/yaw coupling issues at high speeds. But it seems very unlikely to be something that can easily be fixed.

If he's right, it doesn't mean that SS1 can't win the X-Prize, since it's had two successful flights with the problem. It may mean that they may have to go back to the drawing board for SS2, and that the technology's not quite as in the bag as Mr. Branson thinks. As I said, safety issues aside, I think that the market for a rolling ascent is more limited than for one that's smoother and more controlled.

[Another update, after further reflection on Mr. Pike]

He also blew it when being asked why people find this so exciting, whereas they don't seem to care about NASA. He repeated the old cliche about how NASA has managed the seemingly impossible feat of making spaceflight boring, but his (mis)diagnosis was that this was exciting because we could identify with the pilot, whereas NASA had reduced emphasis on showcasing the astronauts since the 1960s.

No, John. People find this exciting, because it offers a promise that they can go themselves.

[Update at 12:45]

A commenter points out that Mike Melvill says that he screwed up. He doesn't say exactly what he did wrong.

Anyway, that's good news, because it means that they don't have to do any analysis to figure it out, and pilot error is easily fixable, either by making the pilot smarter, or by using a different pilot. I was surprised to see Melvill fly this time--I had the impression that he's gotten his ride in June, and was satisfied to let someone else do it. Now, will he be the pilot on the second flight?

[5 PM EDT update]

Derek Lyons asks if the space community has already lost interest in this.

I don't think so. I'll bet that a lot fewer people came up from LA, because they'd already done it once, and the entry price increased quite a bit over the last one. I do think that there's a sense that it's got enough momentum now, and they are content to watch on the web (combined with the fact that, truth be told, like sporting events, the view is much better from home). I'll bet that once it becomes a real race, like the Ansari Cup, there will be big crowds, and it will be crowds of people who weren't necessarily interested in space.

The most important gauge of public interest isn't how many people physically show up to events like this, but how many marketing deals, and investment agreements get signed, and how much continuing buzz it gets in the major media.

Sorry to hear about the DSL, had wondered where you were. Agree on the roll, but eagerly awaiting pilot's report and such. Very much agree with you about John and the coverage on FNC. Can't give it high marks.

Did anybody count how many rolls it made?

I figure about ten during powered ascent, and maybe another six after he shut off the engine.

I've heard it was nearer to 30.

"He also blew it when being asked why people find this so exciting, whereas they don't seem to care about NASA. He repeated the old cliche about how NASA has managed the seemingly impossible feat of making spaceflight boring, but his (mis)diagnosis was that this was exciting because we could identify with the pilot, whereas NASA had reduced emphasis on showcasing the astronauts since the 1960s.

No, John. People find this exciting, because it offers a promise that they can go themselves."

Your comments are reflecting your own biases. Many people still find NASA exciting. You don't. You may be right that the people who find this exciting do so because they like the idea that they can go themselves, but don't paint things in black and white terms--private space: good/NASA: bad.

The roll excursion is indeed a troubling problem. It is my opinion that this same issue also manifested itself in the June 21 flight, although this more modest roll excursion has been attributed to winds aloft. My explanation, which may be proved wrong, is that it is a shed vortex emerging from the leading edge of the wing/body junction on one side and impinging upon the elevon on that side. It will be assymetric, and emerge from the positive-roll side (ie the side that is experiencing positive roll angle). It is a dynamic process that is occurring during the acceleration-portion of this flight phase (thrust, lift, and positive pitch-angle), and it is for this reason that the (steady-state)CFD may not have identified it.
On the other hand, it could be something completely different.......:)

Many people still find NASA exciting.

Of course they do (and I never said otherwise). But many (probably many more) don't. John was asked why people find this more exciting than NASA, and he had a mistaken explanation. I believe that mine is more valid.

I have absolutely no engineering background, but the pilot claims the roll was "human error".

See here:
http://www.spaceflightnow.com/ss1/status.html

Perhaps I straddle a bit -- I still find shuttle missions and stuff exciting, because it's still dangerous and cool and there are still folks getting into space. I find SpaceShipOne and XPrize stuff compelling because I see no reason I won't -- after I save my pennies and the price comes down -- get to fly suborbitally myself and I see a pretty good chance that I may get to fly orbitally, at least in say 30 years or so.

I've said it before, but waiting for NASA to get me into space is like waiting for the DMV to deliver me a Ferrari Dino.

Also, I stuck with CNN this morning, since Miles O'Brien was talking to Dick Rutan throughout the flight and he knew what the hell he was talking about.

I was going to switch to CNN, but I'm having transponder troubles again on my satellite dish. Patricia asked me the other night how I'd managed to break the DirecTV setup such that the only channel that seems to come in reliably is Fox News.

I told her that I'd get a fair and balanced repair team to work on it.

Well, -I- really get turned on by the Mars Rovers. Maybe the perceived level of risk elevates the heart rate of watchers.

Got a call from a media client this AM to fly out and watch (and report on) the second flight -- and it seems so far that it still can occur on Monday.

My interest is -- what mass will replace the load of personal mementoes that were strapped in the two back seats this time? A little bird is telling me that at least Burt, and maybe Paul allen, will be there. But if they got worried by the roll, maybe they can take a third flight later, and stick to Mike and some saleable geegaws.

The amount of swag for sale -- and last flight's M&M stunt which got them a corporate sponsorship, apparently -- makes this whole thing very, very reminicent of "The Man Who Sold the Moon", what with the plan to cancel stamps on the moon, and what not...

Jim O: the PR value of Rutan & Allen flying as passengers can't be overstated.

Is your little birdie telling you anything about Melvill's claim that he (accidentally) initiated the roll? Is this true, or do they have some roll-coupling going on that they don't have a real handle on?

Andrew; For my part, I'm hardly surprised that commercial space flight involves.. well, commerce.

I was showing people in my office the flight through the online webcast. During the start of the ascent phase I started talking about how much it will cost and everyone can go if they can afford it. Then, it started to roll around and around and everyone started laughing like, "yea right, me in that thing - NO Way!!!".

My guess is that Mike will again be the pilot on the next flight and it will be rock steady, while a future pilot of the craft will go up with him. Does the prize allow for two people and a sandbag?

http://www.spaceflightnow.com/ss1/status.html

"Melvill is speaking to the post-flight news conference right now about the unplanned rolling motion.

"I don't think I made a mistake. Bear in mind we haven't be able to look closely at the data. We took a real quick look at and none of us are positive what caused that. It is possible that I stepped on a rudder when I shouldn't have. You get older you can do things like that. We will have to look and see what that was.

"It was at no time any worry for me. I knew the rates could be handled. I was very glad to see that I passed the altitude (62-mile threshold for X Prize) and I waited a little bit longer just to get a little altitude in hand and then I shut (the engine) down 11 seconds early. I had 11 seconds more of burn -- I could have gone to 360,000 feet today -- but I didn't think it was worth taking that kind of risk because we have a second flight to do. It is better to get the altitude, bring it back clean and undamaged."

The thing that's reallys triking to me is that all manned spaceflights launched from the United States in 2004 will be privately funded flights instead of government funded flights.

Ponder that factoid for a few seconds.

The amount of swag for sale -- and last flight's M&M stunt which got them a corporate sponsorship, apparently -- makes this whole thing very, very reminicent of "The Man Who Sold the Moon", what with the plan to cancel stamps on the moon, and what not...

Making money by selling this sort of stuff might very well exceed the potential revenue from selling tickets.

Never discount the revenue stream from an NFL parking lot.

I watched the PC this afternoon: a few points.
First, according to Burt, the pilot switch was made because the pilot orginally slated for this flight had some personal family issues and didn't think e could focus 110% on the training and the flight, so Mike went back in the cockpit.
Also, the CNN anchorwoman and Miles O'Brien re-ran the tape later, and each stopped couting near 40 rolls.
Burt also said that contrary to all rumors that he would npt be flying in SS1 or any subsequent plane until the first commercial flight of Virgin Galactic, and that he and Richard Branson would be on board for that flight, but not for the second X-prize flight.

Pictures of the flight here:

http://www.2020hindsight.org/2004/09/29/ansari-x-prize-x1/

It was interesting noting that the first time around the ground shots were so bad. The guy on Fox mentioned that they'd hooked their camera up "through a telescope" this time ;) (Not 'telescopic sight', he said 'telescope'.)

Did they have anything for the folks on the ground to watch after WK/SS1 left direct visual range?

I'm not saying a torque from the engine flow is certain, but it certainly seems possible. It's happened before e.g. with Ariane

I do agree that inadvertant yaw would make it want to roll but:

1) Melvill is an experienced enough pilot that if ailerons weren't enough to stop a roll he'd try rudder as well, which would take out the yaw. I know I learned that in my first 10 hours flying.

2) this is happening late in the powered flight (both flights), when aerodynamic effects are disappearing. If the roll is caused by aerodynamic forces (e.g. yaw, whether caused by pilot error or an offset thrust vector) and he can correct it with other aerodynamic forces (e.g. aileron) while down low then as the air runs out up high both forces should decrease together and stay in balance. But we're not seeing that. It appears to be getting worse towards the end of the engine run. Which suggests that the force is coming from something non-aerodynamic. Which means the engine as far as I can see.

People have pointed out how a fraction of a degree of misalignment of the thrust axis could cause enough yaw to cause a roll (when in the atmosphere). Exactly the same goes for a fraction of a degree of spiraling of the exhaust as it comes out, except that doesn't depend on having atmosphere.

It's an interesting theory anyway :-)

My stomach sank when the roll started, I hope it is pilot error but they'll need to be sure.

I'm surprised at Rand saying "If he's right, it doesn't mean that SS1 can't win the X-Prize, since it's had two successful flights with the problem." - sure, and the shuttle had loads of succesful flights with O ring burn through and foam flake off. Engineering risks don't work like this.

What's interesting is we didn't see this control issues in the previous rocket tests, is it something to do with the full loading and the climb attitude?

I think Scaled Composites made it quite clear that there were going to be flight instabilities at the apex of the flight trajectory. The nozzle that they are corrently using was never ground tested because it would not have ran correctly at ground level altitudes. The larger nozzle is expected to produce asymmetric thrust velocities. Coupled with the fact that the reaction control system they are currently using is not strong enough to effectively counteract the assymetic thrust velocites makes for a hairy ride at high altitude. Thats why great emphasis was put into the shuttlecock reentry configuration which orients the vehicle back into a proper angle of attack regardless of which way the vehicle is pointed.

Comment made:
>A commenter points out that Mike Melvill says
>that he screwed up. He doesn't say exactly what
>he did wrong.

Rand, everyone... note that the 'screw up' was NOT this flight. He states that LAST flight, (June) the problems were a PIO (Pilot Induced Oscillation)that he got into.

Randy

The data is still 'out' on the cause of the rolling

"The data is still 'out' on the cause of the rolling."

Yes. Melvill's comments were a little ambiguous on this. Immediately after the flight he said that he "might" have hit a pedal. Later, at the press conference, he said that although he might have done this, he did not think he had. They all conceded that a preliminary look at the data did not indicate what happened.

As to whether or not anyone has lost interest, I think that there is at least one other factor that Rand didn't mention already (I agree with the others that he did mention). This was flight 1 of 2 required to win the prize. Although it's great that it was (tentatively still?) successful, it's like the first game of a World Series -- no matter who wins, there's still more ball to be played.

I'd expect that the flight next Monday will have much more publicity, attendance, etc., as it will be the "winning" flight.

I know that for myself, I had hoped to get to go down to Mojave, but don't have the time or money. But if I could only attend one flight, I'd pick the prize winning flight, personally.

If the motor isn't directing the thrust vector through the center of mass, a torque will result. If that torque exceeds the torque authority of the control system about any axis, the vehicle will rotate uncontrolled.

Just a thought. I've seen some bad things happen to a nominally good rocket motor, such as movement of the nozzle throat after protracted action time. That can (and did) result in a misalignment of the thrust vector from its nominal direction.

Yeah, erosion in an ablative rocket nozzle can cause all sorts of fun & entertaining vectoring. Oddly though, it doesn't seem to happen with regeneratively cooled liquid rocket engines :)

Engines on the EZ-Rocket:
S/N 103: 170 runs 2240 sec
S/N 104: 133 runs 1006 sec

Well I too have been bitten by the O-chick. Her name is Sabine Ehrenfeld. I love Google.