Orbital Minotaur I - Manual (Page 48)

Minotaur I User’s Guide Section 5.0 – Payload Interfaces
provide LV minimum structural interface design
criteria for shear, bending moment, axial and
lateral loads, and stiffness.
Another available approach involves the use of a
spacecraft design using the Orbital MicroStar bus
which was successfully developed and flown for
ORBCOMM. The MicroStar bus features a circular
design with an innovative, low-shock separation
system. The spacecraft bus is designed to allow
stacking of co-manifested payloads in “slices”
within the fairing. The bus design is compact and
provides exceptional lateral stiffness. This
approach was flown on the COSMIC mission and
is shown in Figure 5.2.4.1.1-1.
To avoid the complications involved in spacecraft
to spacecraft interfaces and loads, Orbital can
provide a mission unique Multi-Payload Adapter
(MPA). An example of this approach was flown on
the JAWSAT mission, in which the primary payload
(JAWSAT) was a Multiple Payload Adapter (MPA)
from which four small satellites were separated
(Figure 5.2.4.1.1-2). After separating the smaller
“piggyback” satellites, the JAWSAT MPA was also
separated as an autonomous satellite by utilizing
the Orbital 23” separation system and adapter
cone. An updated concept to provide greater
payload options and primary payload volume (by
mounting directly to the avionics assembly without
a separate PAF) is shown in Figure 5.2.4.1.1-3.
For each of these options, integrated coupled loads
analyses will be performed with test verified math models provided by the spacecrafts/payloads. These
analyses are required to verify the fundamental frequency and deflections of the stack for compliance with
the Minotaur I requirements. Design criteria provided by Orbital will include “stack” margins to minimize
interactive effects associated with potential design changes of each spacecraft. Orbital will provide the
necessary engineering coordination between the SV and LV.
5.2.4.1.2. Non Load-Bearing Spacecraft – Dual Payload Adapter Fitting (DPAF)
The Minotaur I DPAF option supports delivery of two independent spacecraft to orbit (Figure 5.2.4.1.2-1).
The lower payload is encompassed inside the 50” DPAF structure. This configuration assumes use of the
Minotaur I 61” fairing that has the available envelope to support a large upper spacecraft and the 50”
DPAF structure. The design of the DPAF incorporates a light weight graphite structure which provides
independent load paths for each satellite. The upper spacecraft loads are transmitted around the lower
spacecraft via the DPAF structure, thus avoiding any structural interface between the two payloads. The
Figure 5.2.4.1.1-1. COSMIC Spacecraft
Configuration Utilized the Orbital MicroStar Bus
to Fly Six SVs
Figure 5.2.4.1.1-2. JAWSAT Multiple Payload
Adapter Load Bearing Spacecraft
Release 3.0 March 2014 35