IRTS : Infrared Telescope in Space

What's the IRTS !?

The Infrared Telescope in Space (IRTS) is described by Murakami et al. 1994, Matsumoto 1996, Murakami et al. 1996; these publications can be found on the IRSA IRTS Bibliography listings. The IRTS is a cryogenically cooled small infrared telescope that will fly aboard the small space platform Space Flyer Unit. It will survey approximately 10% of the sky with a relatively wide beam during its 20 day mission. Four focal-plane instruments will make simultaneous observations of the sky at wavelengths ranging from 1 to 1000 microns. The IRTS will provide significant information on cosmology, interstellar matter, late-type stars, and interplanetary dust. This paper describes the instrumentation and mission.

Characteristics of the IRTS

Weight Total Weight : 183 kg
Cryostat : 128 kg
FPI+telescope : 9 kg
Electronics : 16 kg
Support structure : 18 kg
Others : 12 kg
Dimensions 93cm diameter (cryostat) x 135 cm (ncluding aperture shade)
Power consumption 80 W maximum
Cryostat Superfluid helium, 90 liters
FPI temperature : 1.9 K
Cold lifetime : > 35 days after launch
Telescope 15 cm diameter F/4 Richey-Chretien type
Effective collecting area : 113 cm2
FPIs Near-Infrared Spectrometer (NIRS)
Mid-Infrared Spectrometer (MIRS)
Far-Infrared Line Mapper (FILM)
Far-Infrared Photometer (FIRP)
Telemetry Data rate : 6 kbits/s (visible orbit), 3 kbits/s (invisible orbit)
Observation 20 days, uniform sky survey
Sky coverage Approximately 10% of the entire sky

Photographs of the IRTS

       Cross Section of IRTS                                Telescope & FPI of the IRTS 

(Provided by ISAS.)

FPIs of the IRTS

Four scientific instruments, the Near-Infrared Spectrometer (NIRS), the Mid-Infrared Spectrometer (MIRS), the Far-Infrared Line Mapper (FILM), and the Far-Infrared Photometer (FIRP) are installed in the focal plane of the telescope together with a near-IR sar sensor.