The Spitzer Space Telescope is an infrared space telescope which was launched in the year 2003. It was retired in the year 2020. Following IRAS (1983) and ISO (1995-98), the Spitzer was the third space probe specializing in infrared astronomy. This was the first spacecraft to use Earth’s orbit, which was later used by the Kepler Planet Finder.
Highlights
The Spitzer was the first space probe to use Earth’s orbit. This was the third space probe dedicated to infrared astronomy. The mission in the beginning was planned for a period of 2.5 years. However, it was subsequently extended to five years until the supply of liquid helium on board was exhausted. Liquid helium was used to cool most of the telescope’s equipment.
Instruments carried by Spitzer
- Infrared Array Camera: An infrared camera that operates simultaneously on four wavelengths. Each module used a 256 x 256 pixel detector. The short wave pair used antimonite indium technology and the long wave pair used arsenic-doped silicon impurity ribbon line technology. The main researcher was Giovanni Fazio of the Harvard Smithsonian Astrophysical Center. NASA Goddard Space Flight Center built the flight hardware.
- Infrared Spectrometer: 5.3-14 ?m (low resolution), 10-19.5 ?m (high resolution), 14-40 ?m (low resolution), infrared spectrometer with four submodules operating at wavelengths 19-37 ?m. Each module used a 128 x 128 pixel detector. The short wave pair used arsenic-doped silicon blocking impurity band technology, and the long wave pair used antimony-doped silicon blocking impurity band technology. The main researcher was James R. Hook at Cornell University. Ball Aerospace built this hardware.
- Multiband Imaging Photometer for Spitzer: Three mid-infrared to far-infrared detector arrays. The 24 m detector is the same as one of the IRS shortwave modules. The 70 ?m detector as well as the 160 ?m detector uses gallium-doped germanium, but 160 ?m is added to each pixel to reduce the bandgap and increase sensitivity to this long wavelength. The main researcher was George H. Rieke of the University of Arizona. Ball Aerospace built the hardware.
Spitzer Space Telescope Earth Trailing orbit
Earth’s counter-orbit is heliocentric. This represents the orbit around the sun. In the same orbit, the Earth revolves around the sun. However, the satellite is located at a point moving at a lower orbital velocity compared to the Earth. And it’s getting worse and worse as the years go by. Cryogenic satellites need liquid helium because they are exposed to the strong thermal effects of the Earth when in low Earth orbit. The use of large amounts of liquid helium as a refrigerant reduces the payload mass. This limits the life of the mission. On the other hand, when a satellite enters Earth’s rear orbit, passive cooling is possible.
Discoveries made by Spitzer Space Telescope
The telescope has discovered organic matter, dusty galaxies, debris-forming planetary disks, exoplanets, and hot Jupiter in distant space. The names of hot Jupiters discovered by the telescope are TrES1b and HD 209458 b.
