Falcon first stage finished

Vince Cate wrote:
So far so good!

The launch video is up on the tube already
http://www.youtube.com/watch?v=by-iwbgkaIA

let the armchair analysis rip

"Vince Cate" wrote in message
ps.com...
0156 GMT (9:56 p.m. EDT Tues.)

Musk says the rocket didn't reach the intended orbit and actually may
have re-entered the atmosphere. The rolling motion caused the second
stage engine to shut down early. Despite the problem, Musk considers
this to be "a very good day" for SpaceX.

Considering the second stage didn't get a chance to fire on the first test
flight, I'd say this is progress. :-)

0154 GMT (9:54 p.m. EDT Tues.)

"We did have a roll-control anomoly," Musk says of the second stage.
Some oscillations could be seen in the last bit of video from a camera
mounted on the second stage before the webcast stopped. Fate of the
rocket remains unknown.

Hopefully they have good telemetry from this portion of the flight and will
be able to determine the cause and come up with a fix. This sounds like the
sort of dynamics and control problem that you couldn't really test on the
ground.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

"Vince Cate" wrote in message
oups.com...

Part of the second stage engine is glowing red. If none of it, or all
of it were red, it might be ok. But to see part of it red like this
does not look good.

http://www.flickr.com/photos/jurvetson/

Cool shots.

Looks like the video is here for people like me who missed the live web
feed:

http://www.spacex.com/video_gallery.php

Very cool, even with the second stage problems.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

"Jeff Findley" wrote in message
...
Looks like the video is here for people like me who missed the live web
feed:

http://www.spacex.com/video_gallery.php

Very cool, even with the second stage problems.

The 2nd stage was clearly "coning" near the end of the above video. Looks
like a guidance and control problem. I suppose it could also be a problem
with the 2nd stage engine that the guidance and control system couldn't cope
with.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

"Jeff Findley" wrote:

:
:"Jeff Findley" wrote in message
...
: Looks like the video is here for people like me who missed the live web
: feed:
:
: http://www.spacex.com/video_gallery.php
:
: Very cool, even with the second stage problems.
:
:The 2nd stage was clearly "coning" near the end of the above video. Looks
:like a guidance and control problem. I suppose it could also be a problem
:with the 2nd stage engine that the guidance and control system couldn't cope
:with.

Looked to me like it was some problem that G&C was trying to cope with
(hence the 'coning' of the second stage gimbal) but which was either
getting worse with ascent (eventually exceeding the control authority
of the engine gimbals) or else Guide was 'behind' the problem, leading
to a slow regenerative feedback, at which point the booster starts to
spin because the guidance can't keep up anymore.

If it's the latter sort of timing problem, it really should have been
spotted in simulation. Therefore, I want to say it's the former - a
gradually building aerodynamic instability the magnitude of which
eventually exceeded the control authority of guidance and the motor
gimbals to correct, leading to uncontrolled roll of the vehicle.

Of course, we're all just guessing based on one optical video...

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

"Fred J. McCall" wrote in message
...
Of course, we're all just guessing based on one optical video...

True. Hopefully they've got some good 2nd stage telemetry which will point
them to the root cause. But this wouldn't be the first time that the
simulations all looked o.k. but something unforeseen turned up in the flight
test. It's the unknowns that get you.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

"Jeff Findley" wrote:

:
:"Fred J. McCall" wrote in message
.. .
: Of course, we're all just guessing based on one optical video...
:
:True. Hopefully they've got some good 2nd stage telemetry which will point
:them to the root cause. But this wouldn't be the first time that the
:simulations all looked o.k. but something unforeseen turned up in the flight
:test. It's the unknowns that get you.

Yep. This is why I lean toward it being an actual aerodynamic
instability that is increasing during the flight rather than a pure
G&C 'lag' issue. The latter sort of problem DOES tend to show up
during simulation, while finding the former relies on the fidelity of
the aero model and flow fields that you have for your vehicle (which
you have to fly to get and prove out).

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

0214 GMT (10:14 p.m. EDT Tues.)

Musk says 90 percent of the Falcon 1 rocket's technical challenges
were proven out with this launch. He doesn't foresee needing another
test flight before launching the first operational mission in late
summer carrying the U.S. military's TacSat 2 spacecraft.

I'm surprised at this - would the underwriters insure that payload on an
unproven booster?

"MichaelJP" wrote in
:

0214 GMT (10:14 p.m. EDT Tues.)

Musk says 90 percent of the Falcon 1 rocket's technical challenges
were proven out with this launch. He doesn't foresee needing another
test flight before launching the first operational mission in late
summer carrying the U.S. military's TacSat 2 spacecraft.

I'm surprised at this - would the underwriters insure that payload on an
unproven booster?

What insurance? It's a government payload, and they'll make the
call on whether they want to fly on the third attempt or wait for another
validation flight.

Lots of things were happening on this flight and we need to wait for a
full analysis of what actually happened, and what the necessary fixes
will be. I'm happy that it got as far as it did, exercising all of the
hardware and flight modes. That's how problems get found; the launch
business is not for the timid.

--Damon

On Wed, 21 Mar 2007 15:49:46 -0000, in a place far, far away,
"MichaelJP" made the phosphor on my monitor glow in
such a way as to indicate that:

0214 GMT (10:14 p.m. EDT Tues.)

Musk says 90 percent of the Falcon 1 rocket's technical challenges
were proven out with this launch. He doesn't foresee needing another
test flight before launching the first operational mission in late
summer carrying the U.S. military's TacSat 2 spacecraft.

I'm surprised at this - would the underwriters insure that payload on an
unproven booster?

Military satellites aren't insured.