Orbital Minotaur I - Manual (Page 79)

Minotaur I User’s Guide Section 8.0 – Optional Enhanced Capabilities
sites, the LV switches telemetry output to the
TDRSS antenna and points the antenna towards
a TDRSS satellite. The TDRSS relays the
telemetry to the ground where it is then routed to
the launch control room (Figure 8.8-2). A cavity
backed or phased array antenna can be used
depending on data rate requirements. The
TDRSS system proposed includes the launch
vehicle design, analysis, hardware and launch
vehicle testing. For this option, arrangements
need to be made with NASA for system support
and planning, management, scheduling, satellite
usage, ground operations, and data processing.
8.9. Increased Insertion Accuracy
Enhanced insertion accuracy can be provided
through the use of a Hydrazine Auxiliary
Propulsion System (HAPS). 6DOF analyses show
the HAPS system provides a controlled impulse
to achieve the accuracies shown in Table 8.9-1
(Insertion is for both apse and non-apse).
The HAPS propulsion system consists of a
centrally mounted tank containing approximately
100 lbm of hydrazine and three fixed axial
thrusters. The hydrazine tank contains an integral
propellant management device which supports
several zero gravity restarts. The system is
integrated inside of a dedicated HAPS stage
avionics structure that separates from the Stage 4
assembly. After Stage 4 burnout and separation
from the Stage 4 assembly, the HAPS hydrazine
thrusters provide additional velocity for improved
performance and precise orbit insertion. On the
Minotaur I vehicle, the HAPS is integrated into the
Pegasus-developed extended avionics cylinder
which is used in lieu of the standard Minotaur
avionics structure.
8.10. Payload Isolation System
Orbital offers a flight proven payload isolation system as a non-standard service. The Softride for Small
Satellites (SRSS) was developed by Air Force Research Laboratory (AFRL) and CSA Engineering. It has
successfully flown on numerous Minotaur missions. The typical configuration is shown in Figure 8.10-1.
This mechanical isolation system has demonstrated the capability to significantly alleviate the transient
dynamic loads that occur during flight. The isolation system can provide relief to both the overall payload
center of gravity loads and component or subsystem responses. Typically the system will reduce transient
loads to approximately 25% of the level they would be without the system. The exact results will vary for
Figure 8.8-1. TDRSS 20W LCT2 Transmitter and
Cavity Backed S-band Antenna
Figure 8.8-2. TDRSS Notional Telemetry Flow
Table 8.9-1. Enhanced Insertion Accuracies
Error Type Tolerance
Insertion <18.5 km (10 nmi) (3-σ)
Inclination <0.05° (3-σ)
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