Orbital Pegasus - Manual (Page 76)

Release 7.0 Apr 2010 65
Pegasus User’s Guide
coating or thermal blankets. All work procedures
and added materials must be approved by Orbital
in advance of ring shipment.
10.23. 43 cm (17 in.) Payload Adapter
Authorize by: L-24 months
As a nonstandard service, Pegasus can
accommodate a 43 cm (17 in.) PA. The 43 cm
(17 in.) PA is comprised of a 43 cm (17 in).
Marmon clamp band separation system on a 97
cm (38 in.) to 43 cm (17 in.) adapter cone. Due to
the height of the 97 cm (38 in.) to 43 cm (17 in.)
adapter cone, available payload volume is
reduced by 3.74" relative to a standard 23" PA.
The 43 cm (17 in.) PA can support a payload of
approximately 181 kg (400 lbm) with a c.g. 50 cm
(20 in.) forward of the payload interface plane.
Orbital will perform a mission-specific analysis to
verify payload compatibility as part of this service.
The 43 cm (17 in.) PA mechanical interface is a
circle of 24 equally spaced 0.251” diameter
through holes located on a 17” diameter bolt circle.
The electrical interface for the 43 cm (17 in.) PA
consists of two 42-pin connectors both of which
are mounted on a bracket that spans the inner
diameter of the PA.
The forward placement of the payload may drive
the Pegasus random vibration and drop transient
environmental specifications higher. Orbital will
perform mission-specific analysis utilizing actual
payload mass properties to determine the required
environmental test levels.
There is a performance to orbit penalty of
approximately 2.8 kg (6 lbm) associated with the
use of the 43 cm (17 in.) PA relative to the 97 cm
(38 in.) PA.
10.24. Multiple Payload Adapters Including
Related Mission Integration Support
Authorize by: L-24 months
Pegasus has the capability of flying multiple
payloads in the payload fairing in several different
configurations. For this nonstandard service two
payloads are assumed.
10.25. Dual Payload Adapter with 97 cm
(38 in.) Primary PA
Pegasus offers a Dual Payload Adapter (DPA) that
supports primary and secondary payloads in a
non-load bearing configuration. The DPA uses a
structural cylinder of variable length to support the
primary payload PA. The cylinder encapsulates
the secondary payload. The primary or upper PA
is the standard 97 cm (38 in.) separation system.
The secondary payload is attached to the forward
end of the avionics structure via a 59 cm (23 in.) or
43 cm (17 in.) PA. Following separation of the
primary payload, the secondary payload is
released and pushed out of the DPA cylinder by
the action of the separation system's matched
springs. A separation tip-off and clearance
analysis is performed to ensure that the secondary
payload does not contact the cylinder during
separation. The price of the secondary PA is not
included in this nonstandard service (see Sections
10.25 and 10.26).
The volume available to the secondary payload is
limited by the height of the primary payload, the
height of the primary PA, and tip-off rates of the
secondary payload. The primary and secondary
payloads must share the 10 pass-through circuits
of the standard electrical interface capabilities of
Pegasus. The standard launch vehicle and
payload separation breakwire circuits provided by
Pegasus will be duplicated for both the primary
and secondary payloads.