Orbital Pegasus - Manual (Page 62)

Release 7.0 Apr 2010 51
Pegasus User’s Guide
the propellant loading facilities in the VAB at
VAFB. All launch integration facilities will be
configured to handle these sealed systems in the
integration process with the launch vehicle. The
propellant loading area of the VAB is maintained
visibly clean.
7.1.3. Launch Operations
7.1.3.1. Orbital Carrier Aircraft Mating
The Pegasus is transported on the AIT to the OCA
for mating. This activity typically takes place about
3 to 4 days prior to launch. Once Pegasus is
mated to the OCA, Orbital monitors the Hot Pad
24 hours per day through launch.
The OCA/LPO/Pegasus interface is fully verified
prior to mating the launch vehicle to the carrier
aircraft by performing an OCA Pre-Mate Electrical
Checkout. Mission-unique/payload LPO Station
interfaces are also verified using a mission-
specific EWP prior to Pegasus mate to the OCA.
Using the AIT, the Pegasus ground crew then
mates the vehicle to the OCA.
All OCA/LPO/Pegasus/payload interfaces are then
verified again through a functional test, known as
the Combined Systems Test (CST). The CST also
verifies the interfaces with the range tracking,
telemetry, video, and communications resources.
If the payload has an arming plug that inhibits a
pyrotechnic event, and this plug was not installed
in the VAB, it may be installed at this time through
the fairing access door.
The payload can continue to maintain access to
the payload through this door up to 1 hour prior to
aircraft engine start (approximately T.O. minus 2
hours). After engine #2 start, the nitrogen truck is
disconnected, the GACS is removed, and the
fairing environment is thermally controlled by the
AACS from the aircraft, which flows into the fairing
under the control of the LPO.
7.1.3.2. Pre-Flight Activities
The pre-flight activities and launch checklist flow
are shown in Figure 7-5. The first procedure for
the mission operations team begins after the
range communications checks and setup at T.O.
minus 4.5 hrs. At T.O. minus 3.5 hrs, the LPO
enters the carrier aircraft and powers up Pegasus
upon direction from the Launch Conductor (LC).
Concurrently, final closeout of Pegasus is
accomplished and the range safety engineers
verify that the FTS is functioning by sending arm
and fire commands to the FTS antennas via actual
range assets or a range test van.
Other Pegasus verification tests are then
performed to exercise most aspects of the
Pegasus, ensuring that the vehicle will switch from
carrier aircraft power to internal battery power and
that the IMU, flight computer, and telemetry
system are all working correctly. Payload
operations are verified to ensure that the payload
can be controlled by the LPO control switches as
required. End-to-end checks are made to verify
that Pegasus and payload (if applicable) telemetry
transmissions are received in the telemetry room.
7.1.3.3. Launch Control Organization
The Launch Control Organization normally
consists of three separate groups. The
Management Group includes the Mission Directors
for the launch vehicle and the payload and a
senior Range representative. The Orbital Mission
Director provides the final Pegasus Program
recommendation for launch decision based on
inputs from the Pegasus engineering team and the
LC. Similarly, the Payload Mission Director polls
the various payload personnel to determine the
readiness of the payload for launch, and the
Range representative provides the final Go/No-Go
for the Range.
The second group is the Operations/Engineering
Group, including the LC, the Vehicle and Payload
Engineers, and the Range Control Officers. The
Orbital LC is responsible for running the