NICMOS Cooling System Status
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Transcript of NICMOS Cooling System Status
NICMOSCooling System Status
Larry Petro
April 18, 2002
April 18, 2002 TIPS 2 / 10
Summary
NCC reached 70-K NICMOS neon control temperature
NICMOS SMOV begins 4/19
NICMOSNICMOS
NCSNCS70 K
April 18, 2002 TIPS 3 / 10
Significant events
CPL - NCC interface temperature lowered (4/4) Minimum reservoir temperature -12˚ C (was -10˚ C)
Neon control temperature attained (4/11) Average of NICMOS inlet and outlet temperatures is
70 K NCS performance is nominal
Measured NICMOS parasitic load is 6.1 W– In agreement with predictions– NICMOS MEB is off
Average compressor speed is 7075 rps– 225 rps less than CARD limit
Neon coolant temperature is stable (~0.02 K r.m.s.) NCS power is 380 W
NCC not idled during battery reconditioning
April 18, 2002 TIPS 4 / 10
Cooldown completed
L. Bergeron
70-K control temperature reached
April 18, 2002 TIPS 5 / 10
NICMOS cooldown
L. Bergeron
Inlet @ 63 K
Outlet @ 78 K
Modeled detector temperature is 75 K = 0.5 (T_in + T_out) + 4
April 18, 2002 TIPS 6 / 10
Cooling Rate
Control established
L. Bergeron
Compressor @ 7300 rps
Surging stopped
April 18, 2002 TIPS 7 / 10
NCC performance
L. Bergeron
Surging endsSpeed limit 7300 rps
70-K control reached
Variable heat load
April 18, 2002 TIPS 8 / 10
Environmental influences
C. Long
Orbital variations to maintain constant temperature
Constant speed, variable cooling rate
April 18, 2002 TIPS 9 / 10
Neon coolant temperature stability
C. Long
C. Long
Variation is ~0.02 K r.m.s.
April 18, 2002 TIPS 10 / 10
NCS status & plans
NCS performing nominally Recover NICMOS from safe (4/19)
After completion of 1st battery reconditioning ~0.4 W increase in parasitic heat
Measure NICMOS temperature and stability Control tests with Neon circulator loop
temperature and NICMOS mounting cup thermistor
Verify temperature setability Select NICMOS operating temperature