1. NICMOS Cooling System Status Larry Petro April 18, 2002

2. TIPS 2 / 10 Summary v NCC reached 70-K NICMOS neon control temperature v NICMOS SMOV begins 4/19 NICMOS NCS 70 K

3. April 18, 2002 TIPS 3 / 10 Significant events v CPL - NCC interface temperature lowered (4/4) ä Minimum reservoir temperature -12˚ C (was -10˚ C) v Neon control temperature attained (4/11) ä Average of NICMOS inlet and outlet temperatures is 70 K ä NCS performance is nominal u Measured NICMOS parasitic load is 6.1 W –In agreement with predictions –NICMOS MEB is off u Average compressor speed is 7075 rps –225 rps less than CARD limit u Neon coolant temperature is stable (~0.02 K r.m.s.) u NCS power is 380 W v NCC not idled during battery reconditioning

4. April 18, 2002 TIPS 4 / 10 Cooldown completed L. Bergeron 70-K control temperature reached

5. 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

6. April 18, 2002 TIPS 6 / 10 Cooling Rate Control established L. Bergeron Compressor @ 7300 rps Surging stopped

7. April 18, 2002 TIPS 7 / 10 NCC performance L. Bergeron Surging ends Speed limit 7300 rps 70-K control reached Variable heat load

8. April 18, 2002 TIPS 8 / 10 Environmental influences C. Long Orbital variations to maintain constant temperature Constant speed, variable cooling rate

9. April 18, 2002 TIPS 9 / 10 Neon coolant temperature stability C. Long Variation is ~0.02 K r.m.s.

10. April 18, 2002 TIPS 10 / 10 NCS status & plans v NCS performing nominally v Recover NICMOS from safe (4/19) ä After completion of 1st battery reconditioning ä ~0.4 W increase in parasitic heat v Measure NICMOS temperature and stability ä Control tests with Neon circulator loop temperature and NICMOS mounting cup thermistor v Verify temperature setability v Select NICMOS operating temperature