|
For spacecraft hardware that is contamination sensitive, it is necessary to protect the hardware from inadvertent contamination from external environments. In the case of the Hubble Space Telescope First Servicing Mission hardware, contamination due to particles or non-volatile residue depositions could cause severe degradation in optical performance. Once a hardware component is vacuum baked and certified `clean' from the outgassing perspective, it must be protected from surface contaminants. Surface contaminants such as particles and non-volatile residue will cause light scattering and ultraviolet absorptance on critical optical components. One method of protecting the hardware from contamination effects is to institute the use of protective bags. Bagging of flight hardware is most efficient during the phases that include storage, integration and test, and transportation. For bags to provide an effective barrier and minimize depositions from the environment, the bags must meet several requirements to preclude the bag material itself from becoming a source of contamination to the hardware. These requirements must satisfy cleanliness specifications, in addition to strict safety standards for spacecraft and launch facilities. During the launch site processing of the HST FSM hardware, an innovative design for a protective bag was created to facilitate removal during integration into the payload bay. The protective bag design incorporated a `ripcord' method for removal to minimize contamination on the FSM hardware from Canister handling, facility fall-out, Payload Ground Handling Mechanism transfer, and personnel induced contamination. In addition to cleanliness requirements, the `ripcord' design was required due to accessibility limitations while processed in the Payload Changeout Room.
|
