1. Active Coolers for cooling Infrared Detector on satellite payloads
Presentation By
Milind B Naik
TIFR, MUMBAI
Stirling Cooler

2. Types of coolers Passive Coolers Active Coolers Radiators
Stored Cryogens
Active Coolers
Stirling cycle (this presentation covers this cooler )
Pulse tube
Joule-Thompson
Brayton
Adiabatic Demagnetization
3He coolers
Optical cooling
Peltier effect coolers

3. Passive Coolers Radiators Stored cryogens.
Radiators are panels radiating heat according to Stefan's Law
extremely high reliability
low mass and a lifetime limited only by surface contamination and degradation
limitations on the heat load and temperature (typically in the milliwatt range at 70K )
Multiple stages are often used
Stored cryogens.
Dewars containing a cryogen such as liquid helium or solid neon
excellent temperature stability with no exported vibrations
substantially increases the launch mass of the vehicle
limit the lifetime of the mission to the amount of cryogen stored
STEPHANS LAW :
AMOUNT FLUX FROM BLACK BODY
FLUX : AMOUNT OF ENERGY / SECOND /SQ. CENIMETER
ITS MEASURE OF HOW BRIGHT SURFACE APPEARS.

4. Active Coolers Stirling cycle.
These coolers are based on causing a working gas to undergo a Stirling cycle which consists of 2 constant volume processes and two isothermal processes.
Devices consist of a compressor pump and a displacer unit with a regenerative heat exchanger, known as a `regenerator'.
Stirling cycle coolers were the first active cooler to be used successfully in space and have proved to be reliable and efficient.
Recent years have seen the development of two-stage devices which extend the lower temperature range from 60-80K to 15-30K.

5. Advantages/disadvantages of different types of cooler technology

6. Some examples of missions using active coolers
Missions are listed as vehicle/instrument.
Design lifetime has been quoted if the instrument is yet to be launched
or failed due to another component.
Excluding electronics.
STS/BETSE was a technology demonstrator.
UARS/ISAMS figures per cooler running at 83% stroke.

7. example of missions using active coolers

8. Typical cryocooler to be used for satellite payload
MOTOR
COLD FINGER
RICOR
( ISRAEL)

9. Set of cold-finger available for Cryocooler

10. MTTF : MEAN TIME TO FAILURE

11. Working of stirling cryocooler
Hot side (with heat sink)
Cold side (cold finger)
Hot side
Cold side (cold finger)

12. Working of stirling cryocooler

13. Test-dewar for cryocooler testing

14. Test-dewar for cryocooler testing
Temperature Sensor
Vacuum

15. Various processes involved for testing Stirling cryocooler
Design, development of test-dewar with vacuum seal, feedthrough wires, optical window, temperature sensor integration with cold-finger etc.
Assembly , evacuation of test-dewarCrcycooler assembly
Crycooler Fill and purge with Helium
Various leak tests
Functional tests
Calibrations
Others.

16. Thanks …