Flight Question Shuttle reentery

[wllmpeek]

No translation error to America. Maybe a translation error between "layman's terms" and "dry and boring engineering". I have an engineering background, I read things with some different eyes than the layman.

STS-1 had a cross talking of the yaw jets with the airflow, resulting in unexpected aileron motion to compensate a banking moment. Thats not out of control, the Space Shuttle FCS had been designed for it. It didn't even saturate a FCS channel (which is "out of control" for flight-by-wire aircraft, it means that the control surfaces are at the limit of travel without being able to reduce the attitude error). They tested this on STS-2 further and confirmed on that flight, that the RCS jets energized the airflow and caused the Shuttle to produce more lift on one side.

Again, this wasn't "outside prescribed reentry bank angle parameters". There are no such things, there is a prediction how the shuttle will fly the reentry and an envelope of energy and altitude, which the shuttle must not leave at all costs. There are safe regions in the envelope and not so safe. And avoid at all costs zones.

This quote comes right out of the book you posted earlier as a reference. (From Runway to Orbit) Page 228, last paragraph.

"In fact, his pilot display had a limit of plus or minus 2.5 degrees on the angle of sideslip, and this one had gone plus or minus OVER 3 degrees, so it had actually pegged and sat on the peg awhile," ( I feel this infers it went well past 3 degrees.) "going back and forth as he watched it. John's reaction was that it certainly got his attention. However, I never got a sense of what he thought or what he really felt. He'd been through quite a few incidents in his career, including going to the Moon twice, and I'm sure all of them were scary, but it seemed to me that THIS ONE WOULD HAVE BEEN THE SCARIEST. However, John is very low key, and so his answer of "it certainly got our attention" was probably about as big an admission as we would get from him that he did................."
(Page 228 ends there. Someone has removed page 229 from the text you provided as evidence and doesn't pick up until page 230.)

I don't know how they make the gauges where you are from but here in the US if the gauge only goes to 2.5 and then pegs and holds at 3 that usually means outside the flight parameters. As in, there was no meter to measure the excessive angle.

In addition At the beginning of my contribution to this thread I was simply stating that once during STS-2 the shuttle was manually reentered. (As un-manual as fly-by-wire really is.) I think you're getting hung up on how specifically I am phrasing things.....:tiphat:

 

[Urwumpe]

but it seemed to me that THIS ONE WOULD HAVE BEEN THE SCARIEST.

I marked the really important word, your emphasis is completely displaced. If you read the full story as linked by me, not the google books version with the highlighted word, you will find out, that it was the impression of the author.

Also, the Shuttle wasn't out of control - the sensors still measured the sideslip correctly (peaked at -4°). The crew just had lost the yaw display in the dedicated display system, but not in the CRT and also has not received a warning by the GNC software. And after the short -4° peak, the flight software actually behaved pretty much correctly - if you read the plots of the sideslip angle, you can see that the actual sideslip had been back into the scale after a second, left it again (which likely had been indicated as out of scale by the mechanic indicator) and then settled within scale... but with strong oscillations for about 5 seconds because the control loop overcompensated.

 

[wllmpeek]

Also, the Shuttle wasn't out of control - the sensors still measured the sideslip correctly (peaked at -4°). The crew just had lost the yaw display in the dedicated display system, but not in the CRT and also has not received a warning by the GNC software. And after the short -4° peak, the flight software actually behaved pretty much correctly - if you read the plots of the sideslip angle, you can see that the actual sideslip had been back into the scale after a second, left it again (which likely had been indicated as out of scale by the mechanic indicator) and then settled within scale... but with strong oscillations for about 5 seconds because the control loop overcompensated.

Citation needed...???

This is really specific information. Where can I read this data? Sounds like a fascinating read.

 

[IronRain]

I think this discussion is not relevant for this thread. What about creating a new topic? :thumbup: