PROCEEDINGS ARTICLE | July 29, 2016
Proc. SPIE. 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave
KEYWORDS: Infrared telescopes, Space telescopes, Telescopes, Optical instrument design, Cryogenics, Infrared radiation, Cooling systems, Space telescopes, Cryogenics, Electrical breakdown, James Webb Space Telescope, Space operations
The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is a pre-project of JAXA in collaboration
with ESA to be launched in the 2020s. The SPICA mission is to be launched into a halo orbit around
the second Lagrangian point in the Sun-Earth system, which allows us to use effective radiant cooling in combination
with a mechanical cooling system in order to cool a 2.5m-class large IR telescope below 8K. Recently,
a new system design in particular thermal structure of the payload module has been studied by considering
the technical feasibility of a cryogenic cooled telescope within current constraints of the mission in the CDF
(Concurrent Design Facility) study of ESA/ESTEC. Then, the thermal design of the mechanical cooler system,
for which the Japanese side is responsible, has been examined based on the CDF study and the feasible
solution giving a proper margin has been obtained. As a baseline, 4K / 1K-class Joule-Thomson coolers are
used to cool the telescope and thermal interface for Focal Plane Instruments (FPIs). Additionally, two sets of
double stirling coolers (2STs) are used to cool the Telescope shield. In this design, nominal operation of FPIs
can be kept when one mechanical cooler is in failure.
