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Measured performance and description of the Naval Research Laboratory Solar Coronagraph Optical Test Chamber and instrument clean room

The Naval Research Laboratory recently completed construction of a new instrument handling facility for contamination sensitive optical space flight instruments. The solar instrument test facility includes a clean room for instrument assembly and a relatively large (1.65x104 liters) optical test and calibration vacuum chamber. The performance of each has been verified in preparation for the arrival of the Large Angle Spectrometric Coronagraph (LASCO) instrument. After vacuum conditioning, the chamber had an ultimate pressure of 8 x l0 exp -9 Torr. The chamber ambient vacuum was measured to have no partial pressure peaks greater than 10 exp -10 Torr above 55 atomic mass units as measured with a residual gas analyzer. The clean room was tested and found to be Class 10 in the instrument areas. This paper describes the A-13 clean room and vacuum tank facilities and their experimentally measured performance.