Orbital Minotaur VI - Manual (Page 47)

Minotaur IV • V • VI User’s Guide Section 3.0 – General Performance
3.4. Injection Accuracy
Minotaur IV injection accuracy limits are summarized in Table 3.4-1. Better accuracy can likely be
provided depending on specific mission characteristics. For example, heavier payloads will typically have
better insertion accuracy, as will higher orbits. Furthermore, an enhanced option for increased insertion
accuracy is also available (Section 8.9) that utilizes the flight proven Hydrazine Auxiliary Propulsion
System (HAPS).
Table 3.4-1. Minotaur IV Injection Accuracy
Error Type
Tolerance
(Worst Case)
Error Source
Altitude
(Insertion Apse)
±18.5 km (10 nmi)
Stage 4 motor performance uncertainty and guidance
algorithm uncertainty
Altitude
(Non-Insertion Apse)
±92.6 km (50 nmi)
Stage 4 motor performance and guidance algorithm
uncertainty and navigation (INS) error
Altitude
(Mean)
±55.6 km (30 nmi)
Stage 4 motor performance and guidance algorithm
uncertainty and navigation (INS) error
Inclination ±0.2°
Guidance algorithm uncertainty and navigation
(INS) error
3.5. Payload Deployment
Following orbit insertion, the Minotaur IV
avionics subsystem can execute a series of
ACS maneuvers to provide the desired initial
payload attitude prior to separation. This
capability may also be used to incrementally
reorient Stage 4 for the deployment of
multiple spacecraft with independent attitude
requirements. Either an inertially-fixed or
spin-stabilized attitude may be specified by
the customer. The maximum spin rate for a specific mission depends upon the spin axis moment of inertia
of the payload and the amount of ACS propellant needed for other attitude maneuvers. Table 3.5-1
provides the typical payload pointing and spin rate accuracies.
3.6. Payload Separation
Payload separation dynamics are highly dependent on the mass properties of the payload and the
particular separation system utilized. The primary parameters to be considered are payload tip-off and
the overall separation velocity.
Payload tip-off refers to the angular velocity imparted to the payload upon separation due to payload
center-of-gravity (CG) offsets and an uneven distribution of torques and forces. Separation system
options are discussed further in Section 5.2.4. Orbital performs a mission-specific tip-off analysis for each
payload.
Separation velocities are driven by the need to prevent recontact between the payload and the Minotaur
final stage after separation. The value will typically be 0.6 to 0.9 m/sec (2 to 3 ft/sec).
Table 3.5-1. Typical Pre-Separation Payload
Pointing and Spin Rate Accuracies
Error Type Angle Rate
3-Axis
Yaw ±1.0°
≤1.0°/sec
Pitch ±1.0°
≤1.0°/sec
Roll ±1.0°
≤1.0°/sec
Spinning
Spin Axis ±1.0°
≤10 rpm
Spin Rate -- ±3°/sec
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