Terrence Daniels
July 17th 03, 09:24 AM
Read through the CAIB scenario tonight. What I found especially interesting
was the section on launch winds, and the chart of SSME nozzle movements
during ascent.
What's the granularity for flight control adjustments? I mean, how often do
the computers correct the stack's trajectory? 4 times a second maybe? I
tried counting all the little steps on the chart but they're kinda small. :)
The other thing that I wanted to know was... Is there a way for the
computers to "think ahead" on launch? And if so... How "far" ahead do they
work? The CAIB's description of the -2 deg. yaw on the stack, I think around
Max Q (somewhere in the T+1.00 range) said that it resulted from the flight
controls compensating for a wind that was different than expected. Like the
computers had been told to expect a certain wind shear at that altitude but
it was different than programmed, so Columbia had a bit of yaw... I've read
that SR-71 pilots had to plan their turns minutes in advance, so it makes
sense to me that the flight control system has a "game plan," if you will,
for atmospheric conditions during ascent.
While I think of it... What the hell was happening with STS-109? The section
on 107's re-entry heating has some data from STS-109, and a lot of factors
like temps and heating rates looked really, really high for that mission.
109 was Hubble servicing, IIRC, but it's not like Columbia was carrying
Hubble back with it! Why so hot?
was the section on launch winds, and the chart of SSME nozzle movements
during ascent.
What's the granularity for flight control adjustments? I mean, how often do
the computers correct the stack's trajectory? 4 times a second maybe? I
tried counting all the little steps on the chart but they're kinda small. :)
The other thing that I wanted to know was... Is there a way for the
computers to "think ahead" on launch? And if so... How "far" ahead do they
work? The CAIB's description of the -2 deg. yaw on the stack, I think around
Max Q (somewhere in the T+1.00 range) said that it resulted from the flight
controls compensating for a wind that was different than expected. Like the
computers had been told to expect a certain wind shear at that altitude but
it was different than programmed, so Columbia had a bit of yaw... I've read
that SR-71 pilots had to plan their turns minutes in advance, so it makes
sense to me that the flight control system has a "game plan," if you will,
for atmospheric conditions during ascent.
While I think of it... What the hell was happening with STS-109? The section
on 107's re-entry heating has some data from STS-109, and a lot of factors
like temps and heating rates looked really, really high for that mission.
109 was Hubble servicing, IIRC, but it's not like Columbia was carrying
Hubble back with it! Why so hot?