Space Shuttle Solid Rocket Booster Control Limitations Due
to Failure of an Hydraulic Power Unit
Author(s)
Kranzusch, Kara M.
Advisor(s)
Braun, Robert D.
Editor(s)
Collections
Supplementary to:
Permanent Link
Abstract
The Space Shuttle solid rocket boosters (SRBs) each have two nozzle actuators to provide
thrust vector control (TVC). Two hydraulic power units (HPUs) provide hydraulic pressure
to drive the actuators and are capable of driving both gimbals simultaneously at 5º/s. One
HPU, however, is only designed to drive both gimbals simultaneously at a combined rate of
6º/s. Reduced gimbal rate capability due to failure of an HPU can limit the gimbal’s ability
to keep up with commands and the development of large command-position deltas could
cause loss of control of the actuator. Due to SRB thrust authority during the Shuttle’s first
stage, loss of control of an SRB TVC could result in loss of the vehicle. To study the effect of
a failed HPU during nominal ascent profiles, an SRB actuator was modeled in SIMULINK
and the gimbal drive rate was limited to simulate the failure. The maximum resulting
command-position deltas were calculated to determine control limitations. The required
gimbal rate summation limit to cause loss of control of an SRB actuator in response to an
HPU failure during nominal ascent demands is also estimated. Through this analysis, large
margins are demonstrated against this failure scenario. The availability and feasibility of an
operational response are discussed.
Sponsor
Date
2007-11-21
Extent
Resource Type
Text
Resource Subtype
Masters Project
Rights Statement
Unless otherwise noted, all materials are protected under U.S. Copyright Law and all rights are reserved