Orbital Pegasus - Manual (Page 64)

Release 7.0 Apr 2010 53
Pegasus User’s Guide
the LPO station is supplying external power to the
spacecraft, the spacecraft will be transitioned to
internal power no later than L-6 minutes. At L-45
seconds, the fin thermal batteries are activated
and a sinusoidal fin sweep is commanded by the
flight computer to all fins to verify functionality prior
to drop. The fin sweep telemetry, fin position, and
command current are monitored and verified.
Once this is completed, Pegasus is “Go For
Launch.” The Orbital LC relays this “Go” from the
Pegasus control center to the OCA pilot
commander. After confirmation from the pilot
commander of a Go For Launch, the LC performs
the drop countdown. The pilot releases Pegasus
on the LC’s command. After release, the
Pegasus flight is completely autonomous.
7.1.3.5. Abort/Recycle/Return-to-Base
Operations
Should an in-flight abort call be made, the
approximate time to recycle in the air is 30
minutes. If an in-flight recycle opportunity cannot
be exercised, the minimum stand-down time after
an abort/return-to-base is 24 hours. Orbital plans
and schedules all required contingency landing
areas and support services prior to each launch
attempt. In general, only minimal support services
are available to the payload at contingency landing
sites. Available recycle time is dependent on
payload constraints as well. For example, the
payload must determine battery margins to verify
recycle capabilities. Payload providers must
specify the maximum time they can withstand the
absence of GSE support.
8. DOCUMENTATION
8.1. Interface Products and Schedules
Orbital divides external interfaces into two areas:
(1) interfaces with the Pegasus production team
(i.e., our subcontractors and vendors), typically for
hardware products; and (2) interfaces with
external organizations, which are typically
documentation products and data exchanges.
External organizations with which Orbital will have
information exchanges include the launch vehicle
customer, the payload provider, the range, and
various US Government agencies. The products
associated with these organizations are included
within the 24- to 30-month baseline Pegasus
mission cycle. As such, Orbital references
required dates in a “launch minus” timeframe. The
major products and submittal times associated
with these organizations are divided into two areas
— those products that Orbital produces, detailed
in Figure 8-1, and those products that are required
by Orbital, detailed in Figure 8-2.
Figure 8-1. Documentation Produced by
Orbital for Commercial Pegasus Launch
Services