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After the depletion of cryogen in the dewar NICMOS was unavailable for science from January 1999 to March 2002. To restore and conserve an infrared capability on HST, NASA, together with Creare, Inc., developed the NICMOS Cooling System (NCS). After its installation during Servicing Mission 3B, in March, 2002, the NCS has enabled continued operation of NICMOS by cooling the instrument and its detectors to temperatures around 77 K. This is achieved by a closed-loop circuit which runs cryogenic gas through a coil inside the NICMOS dewar.

The NCS consists of three major subsystems:

  1. a cryocooler which provides the mechanical cooling,
  2. a Capillary Pumped Loop (CPL) which transports the heat dissipated by the cryocooler to an external radiator, and
  3. a circulator loop which transports heat from the inside of the NICMOS dewar to the cryocooler via a heat exchanger.

Additional elements of the NCS are the Power Conversion Electronics (PCE) which provide the up to 400 W power needed by the cooler, and the Electronic Support Module (ESM) which contains a microprocessor to control the heat flow.

Information about the actual on-orbit characteristics of the NCS such as power consumption, lowest possible operating temperature, and temperature stability can be found in the NICMOS Instrument Handbook. Additional information regarding the NCS can be found in the following publications and Instrument Science Reports (ISRs) listed below.

NCS Related Links:

For more specific details on NCS, follow the links to the documents listed below.

NICMOS NCS Documentation


Important updates, discoveries and developments that could potentially affect NICMOS observations, calibration, or data analysis.



The NICMOS Instrument Handbook is the primary guide regarding the characteristics and use of the instrument. The HST Data Handbook is the primary guide for calibration, reduction and analysis of NICMOS data.

Instrument Science Reports

ISRs are technical reports written by members of the NICMOS Group about various aspects of the instrument and data. They usually contain in-depth information about specific topics.

NICMOS ISR 2003-008: NICMOS Temperature Table
A.B. Schultz 01 Sep 2003

NICMOS ISR 2000-006: Results From the NCC/NICMOS Spare Detector June 2000 EMI Test
Glenn Schneider 06 Nov 2000

NICMOS ISR-2000-003 Results of the June 2000 NICMOS-NCS EMI Test
S. Holfeltz 28 Sep 2000

NICMOS ISR-99-001: Analysis, Results and Assessment of the NICMOS Warm-up Monitoring Program
T. Boker 22 Feb 1999

NICMOS ISR-99-001: Analysis, Results and Assessment of the NICMOS Warm-up Monitoring Program
T. Boker 22 Feb 1999

NICMOS TIR 98-001: NICMOS/NCS EMI Test Data Results
L. Bergeron 04 Nov 1998

NICMOS ISR-98-001: Cosmic Ray Persistence in NICMOS Data
J. Najita 25 Feb 1998

Papers and Proceedings

Selected NICMOS related published papers and workshop proceedings.

Paper from 2002 SPIE Meeting: A Mechanical Cryogenic Cooler for the Hubble Space Telescope
Nicholas Jedrich, Darell Zimbelman, Walter Swift, Francis Dolan

Presentation from 2002 SPIE Meeting: A Cryogenic Cooling System for Restoring IR Science on the Hubble Space Telescope
Nicholas M. Jedrich, Teri H. Gregory a , Darrell Zimbelman, Edward S. Cheng, Larry D. Petro,,Christine E. Cottingham, Matt T. Buchko, Marc L. Kaylor e , Francis X. Dolan

Properties of PACE-I HgCdTe Detectors in Space - the NICMOS Warm up Monitoring Program

EMI Noise Properties of the NICMOS Cooling System as Seen by a NIC3 Flight Spare Detector


Cookbook style instructions, prescribed procedures, and helpful tips.

Space Telescope Analysis Newsletters

STANs contain useful information regarding calibration and data reduction.