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Facility 239 is a horizontal, medium-sized, thermal vacuum test chamber that is equipped with a viewport to accomodate an external solar simulator. Chamber evacuation is provided by a rotary piston mechanical pump and cryopumping system. A sliding gate main valve allows chamber access while the cryopumping system is being established. The facility is used for thermal vacuum and thermal balance testing, and baking out test items. Any of three solar simulators may be used for tests with solar requirements. A clean tent at the chamber entrance provides class 10,000 cleanliness conditions.

Mode of Operation

The test item is mounted on the portable payload fixture which is positioned at the chamber door. An overhead rail is also available for mounting purposes. After instrumenting the payload with thermocouples, it is rolled into the chamber. Ground support equipment cabling is connected through the penetration plates and ambient functional checks are performed. An auxiliary liquid helium cooled shroud can be installed to provide an ultracold payload environment. The cryopump requires 4 hours establishing time prior to chamber pump down.


Parameters
Test Pressure: <67µPa (5 x 10-7 torr)
Shroud Temperature: GN2 mode -140°C to +100°C , LN2 mode -190°C
Chamber Pumping Speed: 20,000 lit/sec @ 133 µPa
Evacuation Time: Atm to 1.3 Pa in 1 hr. , 1.3 Pa to 133 µPa in 5 hrs.


Physical Characteristics

Test Volume: 7' x 8'
Payload Support: Wheeled cart - 5,000 lb. capacity
Viewports: 12" diameter quartz window
Std. electrical feedthroughs: 61-pin, 37-pin, 7-pin, 4-pin, RF


Integral Instrumentation

Pressure: Capacitance manometer - Atm to 10-3 mmHg
Ion Gauge: 10-3 mmHg to ultimate
Payload Temperature: 125 thermocouple channels
Contamination Monitor: TQCM, coldfinger, residual gas analyzer