Orbital Minotaur VI - Manual (Page 59)

Minotaur IV • V • VI User’s Guide Section 4.0 – Payload Environment
4.6.3. Nitrogen Purge (Non-Standard Service)
If required for spot cooling or purging of a payload component, Orbital will provide GN2 flow to localized
regions in the fairing as a non-standard service. This option is discussed in more detail in Section 8.3.
4.7. Payload Contamination Control
All payload integration procedures, and Orbital’s contamination control program have been designed to
minimize the payload’s exposure to contamination from the time the payload arrives at the payload
processing facility through orbit insertion and separation. The payload is fully encapsulated within the
fairing at the payload processing facility, assuring the payload environment stays clean in a Class
100,000 environment. Launch vehicle assemblies that affect cleanliness within the encapsulated payload
volume include the fairing and the payload cone assembly. These assemblies are cleaned such that there
is no particulate or non-particulate matter visible to the normal unaided eye when inspected from 2 to 4
feet under 50 ft-candle incident light (Visibly Clean Level II). After encapsulation, the fairing envelope is
either sealed or maintained with a positive pressure, Class 100,000 (ISO 8) continuous purge of
conditioned air.
If required, the payload can be provided with enhanced contamination control as an option, providing a
Class 10,000 (ISO 7) environment, low outgassing, and Visibly Clean Plus Ultraviolet cleanliness. With
the enhanced contamination control option, the Orbital-supplied elements will be cleaned and controlled
to support a Class 10,000 clean room environment, as defined in ISO 14644-1 clean room standards
(ISO 7). This includes limiting volatile hydrocarbons to maintain hydrocarbon content at less than 15 ppm.
Also with the enhanced contamination control option, the ECU continuously purges the fairing volume
with clean filtered air and maintains humidity between 30 to 60 percent. Orbital’s ECU incorporates a
HEPA filter unit to provide ISO 7 (Class 10,000) air. Orbital monitors the supply air for particulate matter
via a probe installed upstream of the fairing inlet duct prior to connecting the air source to the payload
fairing.
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