SS-1 flight

Anybody watch Mike Melvile ride Rutan's space vehicle again yesterday? I can't believe he got that wild roll excursion under control without the thing swapping ends on him. He's either very lucky or has major quantities of the right stuff.
I almost had a heart attack watching the video of the flight, it looked like the thing didn't stop spinning until looong after the wings had been dropped into reentry configuration.
Glad he made it, and hoping Rutan and his gang figure out what happened before they strap Melvile into that thing next week......

Mike is a very experienced test pilot--been with Burt for a long time.

FWIW

LAST EDITED ON Sep-30-04 AT 11:03 AM (CDT)
 

The press had that story all wrong.

There was a roll that went on during the first flight and that may have somehow propgated amonst the press and got picked up by a bunch of people who don't know what they are looking at.

A colleague of mine from Air&Space was at the event in the media area and at the post flight interview. Melvillle stressed in the interview that at no time was there a control problem with the airplane. In short, the immediate post flight report was "No Squawks!".

Burt encourage use of the controls and Melville did manuver the airplane a lot, including an attitude adjustment at apogee to get a good photo out the window.

http://www.space.com/missionlaunches/xprize_postflight_040929.html

I talked with my colleage yesterday by phone and she was adamant that nothing had gone on that was difficult. Since she covers Space for the Planetary Society and has been on the space beat for a long time, I take her word for it.

"Flawless test flight sets stage for new age of civilian spaceflight." makes a less interesting headline than "Spacecraft recovers from harrowing roll to land safely."

The next flght, which should claim the X-Prize and put the SpaceShipOne in the National Air and Space Museum, is scheduled for Monday the 4th.

Get your VCR's loaded and programmed.

History is a makin'.

Cy

>
>The press had that story all wrong.
>
>There was a roll that went on during the first flight and
>that may have somehow propgated amonst the press and got
>picked up by a bunch of people who don't know what they are
>looking at.
>
>A colleague of mine from Air&Space was at the event in the
>media area and at the post flight interview. Melvillle
>stressed in the interview that at no time was there a
>control problem with the airplane. In short, the immediate
>post flight report was "No Squawks!".
>

I might disagree. The rolling on this flight, and the attitude control problems on the previous flight, appeared to be functions of the same basic factor - severe effective sweep angle coupling yaw AoA into roll. On the previous flight, it was attributed to upper-atmosphere wind shear, this time to several different things before they settled on "pilot error". I think they understand that part of the problem well, and it may not effect the functionality of the spacecraft to do the mission, but that was definitely not intentional, and AT BEST the stability in roll would appear to be minimal. There is no doubt that it was diverging in roll until aerodynamic effects went away sufficiently to allow the RCS to overcome it.

I have to wonder if they have sufficient instrumentation to find the true cause, and are half guessing. I don't really know, of course.

I got lucky, not knowing a thing about the flight yesterday, just as I was taking a break from whatever I was doing in my shop, I turned on the boob toob just as Fox broke to the inflight pics about 1 minute before release. Talk about blind luck!

I agree that the roll appeared very divergent and scary. Hey Brett, what do you mean? Appears (parsing that as best I can!) that you mean some sort of ruddering was causing the roll? I also wondered even if it did depart (and tumble), is there enough air up there to tear the thing apart? Or would G forces and speed break it up?

In any event, pretty impressive. I was glad I saw it. I was duly unimpressed that my kids at school didn't know a thing about it...

Wishin' them luck on Monday,

Tools

When the US Man to the Moon program was in full swing, I talked my 6th grade teacher, Mr. VanAntwerp, highly decorated Korean War Marine, into letting the class watch the first launch of the Saturn V. It was an unmanned test shot. What a hoot. No one knew what the sound and shock waves off of the engines would do. I saw Walter Cronkite and an Apollo astronaut stand up and hold the plate glass window up in broadcast central to keep it from falling in on them as the blast waves reverberated across the marshes at Canaveral. That launch was awe inspiring. Everyone in the class that I was a geek for getting them to watch until that Dinosaur of a rocket lifted off. Then they couldn't quit talking about it the rest of the day. For a day, I was the smartest kid in class. Different time and day.

>I agree that the roll appeared very divergent and scary.
>Hey Brett, what do you mean? Appears (parsing that as best
>I can!) that you mean some sort of ruddering was causing the
>roll?

No, I was more in the area of thrust vector misalignment resulting in a yaw trim angle to hold the heading. Crabbing slightly sideways, in other words, to make up for some offset thrust. Then that coupling into roll. It's also in the same vein as the "wind shear" explanation from before. Accelerates the entire time the engine is firing, then quits at cutoff and the remaining angular momentum is removed with the thrusters at altitude.

I know they have had some nozzle erosion problems and that's one potential effect of erosion. Not to mention that just plain old asymmetry in an uneroded nozzle/injector/fuel slug.

All speculation, of course. But it's just the sort of thing that a less-experienced* (with rocket propulsion) group might not immediately grasp.

>I also wondered even if it did depart (and tumble),
>is there enough air up there to tear the thing apart? Or
>would G forces and speed break it up?

Well, apparently not! I don't know what would happen on re-entry, but it's not exactly coming in from orbit, and it is supposed to be aerodynamically stable in the "shuttlecock" configuration.

Brett

*or even those who should know better. I am sitting 5 feet from a very experienced propulsion engineer that had not considered the potential thrust vector misalignment effects on a particular bi-prop liquid apogee engine. I noticed it when looking at our torque budget. We had to go back to the vendor and get them to put in a test procedure to measure it. They had gotten away with ignoring it in the past, but they had some otherwise unexplained "events", as well.

>>
>>The press had that story all wrong.
>>
>>There was a roll that went on during the first flight and
>>that may have somehow propgated amonst the press and got
>>picked up by a bunch of people who don't know what they are
>>looking at.
>>
>>A colleague of mine from Air&Space was at the event in the
>>media area and at the post flight interview. Melvillle
>>stressed in the interview that at no time was there a
>>control problem with the airplane. In short, the immediate
>>post flight report was "No Squawks!".
>>
>
> I might disagree. The rolling on this flight, and the
>attitude control problems on the previous flight, appeared
>to be functions of the same basic factor - severe effective
>sweep angle coupling yaw AoA into roll. On the previous
>flight, it was attributed to upper-atmosphere wind shear,
>this time to several different things before they settled on
>"pilot error". I think they understand that part of the
>problem well, and it may not effect the functionality of the
>spacecraft to do the mission, but that was definitely not
>intentional, and AT BEST the stability in roll would appear
>to be minimal. There is no doubt that it was diverging in
>roll until aerodynamic effects went away sufficiently to
>allow the RCS to overcome it.
>
> I have to wonder if they have sufficient instrumentation
>to find the true cause, and are half guessing. I don't
>really know, of course.
>
> Brett

They may "understand" the roll issues if they are attributing them to assymetric erosion of the nozzle on their motor. AWST had printed some statements by the Rutan team that nozzle wear on the larger engine (the type flying now)might cause thrust vectoring to a degree that could impair controllability to some extent. That might be a possible explanation as to why he was able to hang on to the thing ok for most of the burn-the erosion could not be significant early in the motor run.-later on, as aero forces diminish and the nozzle is at maximum wear, it might be different. If nozzle wear is one of the players here, the pilot of that thing might get some new bizarre handling issue on every flight, as no two motors are going to burn identical with respect to the nozzle. I guess thats why it will end up in a museum after the next flight, and maybe for the best.

I read all the above messages but I'm pretty sure I heard the pilot, in an interview, say he thinks he may have accidently hit the rudder pedals.

He may have said that to down play the event.

I think the attitude at Rutan's camp is that the thing certainly took off on them but did not get 'Out of control". No pilot wants to admit that, of course until there is literally no recourse but the eject handle and a quick prayer. (Remind me sometime to tell you the old joke about the student and the SNJ.)

Clearly some roll is going on that was unanticipated. I don't think the reason why is precisely understood, or perhaps Rutan's team has one theory and there is another answer.

This is a single purpose ship, designed to do two things--Win the X Prize and gain some data in the process. As such, it's going to be a little squirrely. I expect politically, they don't want to spook the sponsor by saying the spacecraft is uncontrollable.

It all depends upon what you consider under control.

I rode through a lomchevak a couple of weeks ago in an Edge 540 and the horizon line was gyrating around at very high rates as a climbing outside snap-roll diverged into a pure negative pitch tumble at the top of a parobolic arc and we flirted with an inverted spin until recovery was initiated. I saw the world going by out the canopy exactly the way it is supposed to, watch the control input shift at the right moment to force the tumble and we came out of it on a down line with about an eighth of a roll to line up with the imaginary show line. At no time did I think we were 'out of control', but to the uninitated eye, the airplane was tumbleing end over end with any sense of aerodynamic flight completely lost.

So were we out of control?

Not really.

According to Mike Melville, neither was he.

But I don't doubt that SS1 is subjected to some forces the designer did not fully understand and can get a little squirrly on the way up.

That's the nature of the mission and I'm all for these guys going out and doing what they are doing. Might take a couple of design variations but that basic concept ought to be extensible to carry a few passengers. The sooner we get civilian commercal access to space underway, the better.

The analogy I might make is that Lindbergh very barely got the Spirit of St. Louis airborne out of Roosevelt Field on the morning of May 21. 1927. But he got it airborne and the effect of the flight was profound beyond all the actual practical value. This is the same deal.

Read somewhere that they are getting sweep back induced roll couple and they know what to do to get rid of most of it "on the next one" Do you know that the Voyager was stressed for 1G! Bert will take it to the edge. I made a visit there back in 91 or 2. Way cool stuff going on and for VERY small bucks. Raytheon could not design a single family of screws with what they have in the whole program.

> Read somewhere that they are getting sweep back induced
>roll couple and they know what to do to get rid of most of
>it "on the next one" Do you know that the Voyager was
>stressed for 1G! Bert will take it to the edge. I made a
>visit there back in 91 or 2. Way cool stuff going on and
>for VERY small bucks. Raytheon could not design a single
>family of screws with what they have in the whole program.

Steve,

I believe that the Voyager would have to be stressed for more than 1G as we all are at 1g just standing still. Just a thought....Hmmmm?

Well, in theory, being a flight around the world, they didn't have to turn...

Tools

Gee Mike, you are so right, what was I thinking? I'll keep that in mind at my next Air Show.... I just won't turn and I will be so much more comfortable !!!

Years ago we did a study on asymmetric cooling of the propellent in the space shuttle booster as it crossed the country to see if it would have much affect (solids burn-rate is affected by propellent temperature.) We were concerned that since the motor was transported on its side and was cooling down from casting, the top side would be radiantly heated, the bottom not, and we could have the motor end up in Canaveral with one side warmer, and faster burning, than the other.

Also, maybe they should find themselves a Moog LMTVC system off an old Minuteman 3rd stage to control their thrust directionality.

Scott

I don't mean to knock anyone I really enjoy reading the responses to the tech stuff that people post here I really do enjoy it! But on this one I have to put in my laymen opinion. Ok so there was a bit of a problem with the role rate so what lets think about what these guys did!!They built a rocket that went into low orbit and came back down safley!! I don't care about what or why all I know is that they did it!! And to me thats all that matters.I vividly remember driving back from the cottage and on the radio we heard that man has landed on the moon (huston the eagle has landed)I was only 7 at the time but I remember it like it was yesterday! My mom then woke me up to see mans first steps on the moon!! Now here we are 2004 and we have a privatly funded and privatly built craft that has gone into low space the same place the X-15 went funded by millions of nasa money. and they are doing it on a fraction of the cost so I say the heck with the thech behind it lets just enjoy the fact that they are doing it and say three cheers for Burt Ruttan and GO FOR IT!!!
Again I do love reading the tech stuf on this forum but this time who cares they put a craft into space!!!!!
Dwayne
P.S.
Leonard
We or maybe I could use spell check

LAST EDITED ON Sep-30-04 AT 08:53 PM (CDT)
 
>Lets think about what these guys did!!They
>built a rocket that went into low orbit and came back down
>safley!!

Well, you really need to understand what they have done in laymans terms.

The edge of space is arbitrarily defined as 328,000 ft - 100KM -- for purposes of the X-Prize they are trying to win.

On the first flight they went to 328,491 feet. 500 feet more than they needed to achieve out of 328,000, an excess positive performance factor on the order of 0.0015243902439, give or take some rounding error.

The recent record attempt they did a little better.

But they are merely sticking the nose of the craft into the edge of defined outer space and are WAAAYYYY short of low Earth Orbit. Something like 35 times the energy short, if I remember right. And they are haulling a couple of bodies and some M&M's up there when they do. The shuttle carries tons of stuff into ISS orbit.

So what the achievement is is really symbolic, not functional. They are sub orbital joyriding, not orbital working/living in space.

That said, the symbolism is what is to applaud.

We can only hope that Rutan inspires from this generation what Lindbergh did from his.

Cy.

>
>We can only hope that Rutan inspires from this generation
>what Lindbergh did from his.
>
>Cy.

Highly unlikely, unless he develops some sort of video game that puts you in the seat of SS1 and allows you to blast aliens from low earth orbit.

Is the nozzle easily changed out in a week or so? Is it allowed under the rules? I struggled thru most of the webcast, they said on the first flight a thruster that opposes the roll heated up and timed out as it is supposed to. It came back during the ride down. Is that what we saw on this flight? Possibly the thruster was opposing the roll from the beginning of the burn, then timed out before cutoff? It kept rolling for at least 40 seconds after cutoff, so it looks like that thruster was cooked again. That it had to work so hard again suggests that they didn't change the nozzle? Don

Is there any possibility the roll was intentional, perhaps to offset any yawing that might have led to an uncontrolled or unanticipated flight part? I guess I'm thinking of spiral rifling to keep a straight flight path against other forces which would otherwise cause divergence from the desired flight path.

Al,

General Dynamics rolled the Stinger missile for that very reason. The rolling canceled out the perturbations of the solid fuel rocket nozzle. But, since pilots hate high roll rates over an extended period of time, because it tends to make one susceptible to coriolis, I doubt that Mike Melville rolled the Spaceshipone intentionally.