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