or assists in controlling, most of the shuttle systems.
- The vehicle
relies on computerized control and monitoring for successful performance.
software is divided into two major groups: system software
and applications software.
identical computers aboard the orbiter control vehicle systems.
functions for all mission phases requires about 400,000 words
of computer memory.
CRT Display System
on the flight deck allow onboard monitoring of systems, software
processing and manual control for crew data and software manipulation.
GPC complex requires an accurate time source because its software
uses GMT to schedule processing.
Data Bus Network
is divided into specific groups that perform specific functions.
MDMs convert and format serial digital GPC commands into separate
commands for various vehicle system hardware.
signalls to arm and safe pyrotechnics during SRB/ET separation.
Bus Isolation Amplifiers
devices for the GSE/LPS and SRB MDMs.
fifth GPC, loaded with different software, provides backup
in case primary GPCs fail.
Navigation and Control
- GNC software
commands effect vehicle control and provide sensor data needed
to compute these commands.
Control System Hardware
to one of eight flight-critical MDMs.
IMUS, tacan units, air data probe assemblies, and more.
of an all-attitude, four-gimbal, inertially stabilized platform.
star tracker units are part of the navigation system.
Optical Alignment Sight
if IMU alignment is in error more than 1.4 degrees.
slant range and magnetic bearing to ground station.
information on the movement of the orbiter in the air mass.
Scan Beam Landing System
during landing phase to determine slant range, azimuth and
elevation to landing runway.
absolute altitude from the orbiter to nearest terrain within
beamwidth of orbiter's antennas.
vehicle acceleration along lateral and vertical axes.
Rate Gyro Assemblies
by flight control system to sense roll, pitch and yaw rates
during ascent and entry.
Rocket Booster Rate Gyro Assemblies
as feedback to find rate errors from liftoff to SRB separation.
by flight crew to gimbal engines and OMS/RCS systems.
for manual control of translation along the longitudinal,
lateral, and vertical axes to control RCS.
Stick Steering Push Button Light Indicators
control stick mode.
orbiter rotation about the yaw axis by positioning the rudder
during atmospheric flight.
during ascent to vary thrust level of main engines; used during
entry to control aerodynamic drag.
manual control for positioning body flap during entry.
signals to GPCs, prohibiting execution of related software
commands while RHC is active.
to move the aerosurfaces in roll, pitch and yaw.
commands during atmospheric flight, causing aerosurface deflections.
of several software modules that interpret maneuver commands
and generate commands for the appropriate effectors.
thrusting periods can be used to correct or modify the orbit
boxes are situated in several locations around the orbiter.
the flight crew with data required to fly the vehicle manually
or to monitor automatic FCS performance.
attitude data, including attitude rates and errors.
a pictorial view of the vehicle's position.
vehicle angle of attack.
vertical acceleration, vertical velocity, barometric altitude
and radar altitude.
actual and commanded positions of elevons, body flap, rudder,
aileron and speed brake.
Control System Push Button Indicators
moding requests to digital autopilot.
RCS jet comands by axis and direction.
- Senses linear
acceleration along the Z axis of the vehicle.
miniprocessor that cues the commander during final landing approach.