[net.columbia] ET separation question

brt@whuts.UUCP (B Reytblat) (02/04/86)

While looking through "Space Shuttle Operator's Manual", I noticed a set of
switches and buttons labeled "SRB Separation" and "ET Separation". 
There appears to be an arming switch and a firing button. These controls are
located on panel C3, on the center console, just below the SSME cut-off controls.

My questions are:
1.Are these separation controls connected directly to the separation ordnance
or are they monitored by the GPC's, which then control the ordnance.

2.If so, are there additional criteria, which the GPC's will check before
firing separation charges, or do the controls have absolute authority?

3.What I am trying to get at is, had Dick Scobee known about the problem,
was there anything he could have done before SRB sep? As he was the commander,
I presume it would have been his call.

4. How fast would the fully loaded orbiter be able to get away from the SRB/ET stack
using RCS, OMS and whatever aerodynamic controls were still effective? Would it be
possible to regain control of the attitude of the orbiter?

5.Had they in fact been able to separate from ET in time, what are the likely
problems they would encounter? Would the turbopumps spin out of control after
loss of fuel pressure, and rip themselves and the after portion of the orbiter to
bits? Would the remnants of LOX and LH2 come in contact around ET umbilical
doors, now open? Would the stack burn them as it goes by? How high would they
have to have gotten to have enough energy (kinetic/potential) to get back to
KSC?

Depending on the answers to these questions, there might be a justification
to introduce a new abort mode, Boost Phase Abort, to be active until a few seconds
after SRB sep.

And yes, virginia, i have heard that this option was considered and rejected
by NASA. Having learned the alternative, they might want to go through the
analysis once more.

Ben Reytblat
AT&T Bell Labs.

...!whuts!brt