Orbital Pegasus - Manual (Page 71)

Release 7.0 Apr 2010 60
Pegasus User’s Guide
10.5. Optional Payload/Vehicle Integration
Environment
Authorize by: L-20 months
Orbital is capable of providing a payload/vehicle
integration environment that is clean, certified, and
maintained at ISO 14644-1 Class 7 (10,000), to
support payload integration through fairing
encapsulation. As a part of this service, Orbital
will provide and certify a Class 7 softwall
cleanroom. The Pegasus Stage 3 motor, avionics
section, and fairing halves will be located within
this area. As much as possible, all integration
activities will be performed within the cleanroom.
All personnel will follow appropriate Class 7
cleanroom practices. Note that the softwall
cleanroom does not allow for overhead crane
operations. If the facility crane is required to
support payload mate to the launch vehicle, the
spacecraft and launch vehicle avionics section will
be bagged and the cleanroom will be moved to
allow crane access. The cleanroom will be moved
back into position after the mate operation is
complete. For spacecraft using a handling fixture
for mate operations, all activities can occur within
the cleanroom.
10.6. Enhanced Fairing Environment
Authorize by: L-20 months
Orbital can provide payload fairing purge with air
meeting ISO 14644-1 Class 7 (10,000), in
accordance with TD-0289, Pegasus Con-
tamination Control Plan, NASA ISO 14644-1 Class
7 Missions. This task includes installing,
operating, monitoring, and cleaning special HEPA-
and carbon-filtered, conditioned air supply
systems during four phases of integrated
operations:
 Inside the integration facility VAB;
 During transport to Hot Pad;
 During Hot Pad ground operations; and
 During OCA mated operations.
10.7. Enhanced Fairing Internal Surface
Cleaning
Authorize by: L-20 months
Orbital can clean, certify, and maintain internal
surfaces of the Pegasus payload fairing to IEST-
STD-1246D, Level 600A or 500A. This involves
increased levels of precision cleaning of the
internal fairing surfaces prior to payload
encapsulation, additional surface cleanliness
measurements to verify surface cleanliness, and
additional handling controls to maintain
cleanliness.
10.8. Hydrocarbon Monitoring
Authorize by: L-20 months
Orbital will provide monitoring of hydrocarbon
levels during all integrated payload/Pegasus
operations. This service comprises the
installation, calibration, and frequent round-the-
clock monitoring of fixed and portable hydrocarbon
(VOC) detectors in the VAB, during rollout to Hot
Pad, and during Hot Pad operations through
fairing closeout.
10.9. Instrument Purge System
Authorize by: L-20 months
Payload Instrument Purge is an optional service
that provides up to two dedicated nitrogen lines to
payload defined locations in the fairing. Flow is
turned on/off by the LPO at payload discretion.
Flow rate and nozzle location are documented in
the mechanical ICD. Flow is controlled within
±10% by a mission-unique choked orifice. Flow
rates can be selected between 0 and 535 slpm
(19.2 scfm). Nitrogen flow is limited to 267 slpm
(9.6 scfm) per nozzle. Higher flow rates cannot be
maintained indefinitely in flight due to aircraft
nitrogen tank limitations. Total nitrogen mass for
the payload purge is limited to 200 lbm after the