Spitzer Space Telescope – The Last of Great Space Observatories

The Spitzer Space Telescope belongs to the class of Space Telescopes and is a part of NASA’s Great Observatories. Formerly known as the Space Infrared Telescope Facility (SIRTF) was launched in 2003, and after completing its mission, retired in January 2020. Although it had to go a long way for another five or more years, unfortunately, the onboard liquid helium got exhausted. Hence, there was nothing left to cool the telescope at the same temperatures.

There was no way that the telescope could operate at higher temperatures or without the liquid helium. As per the customary practice of NASA, the telescope got its name after a series of successful operations on December 18, 2003.

Principle Type of Spitzer Space Telescope

The Spitzer Space Telescope is a reflector type telescope with two curved mirrors at both ends.

Light Collecting Instrument

It used Beryllium metal in the form of a mirror to collect the IR radiations.

The distance of Spitzer Space Telescope from the Earth

The Spitzer Space Telescope is far from the surface of Earth. However, it follows the same orbit around the Earth.

Observable Wavelength of Spectrum

The Spitzer Space Telescope observed the light in the Infrared region of the Electromagnetic radiation spectrum.

The Outcomes of its Launching

The SST saw through the cloud of dust formed in the galaxy. Hence, it allowed us to study the process of star formation and black holes.

The Spitzer Space Telescope spent 2 ½ to 5 years studying the infrared (IR) light. Although telescopes on mountains could study certain infrared radiation, most infrared radiation is absorbed by the atmosphere of the Earth.

Spitzer got its name after the astrophysicist Lyman Spitzer Jr., who was the first scientist who proposed the idea of introducing telescopes in space. This high functioning IR telescope is the last of four telescopes in NASA’s Great Observatories program.

Keeping the Telescope Cold for its Proper Functioning

Since it studies infrared light, which has a large amount of heat, it must be kept extraordinarily cold to keep it working. It prevents the telescope’s own heat from interfering with the heat produced as a result of infrared (IR) radiations from space.

Moreover, the Spitzer Space Telescope has an extremely well-insulated system to prevent it from heating up. The telescope has a liquid helium tank, which serves the purpose of keeping the telescope and its different parts cold to as low as 1.4 Kelvin. That’s super close to 0 Kelvin, or “absolute zero,” which is the lowest temperature at which any motion or movement of the particles or molecules stops.

Location of the Spitzer Space Telescope

As the other telescopes orbit close around the Earth, but the Spitzer is unable to do so. Since it needs to be really cold – we cannot keep it near the Earth as the heat from the core of the planet could lead to its dysfunction.

Instrumentation of the Spitzer Space Telescope

Being a basic reflecting telescope, it has a mirror made of beryllium and the following functional parts:

  • Solar panels to provide power to the telescope.
  • A Camera to record a different range of Infrared radiation.
  • A Spectrograph that observes and detects evidence of stars and black holes.

Infrared Array Camera (IRAC)

It is a camera that operates and detects four different wavelengths in two modules simultaneously. The short wavelength pair uses the technology of indium antimonide; however, those of longer wavelength use the arsenic doped silicon band conduction technology.

Infrared Spectrograph (IRS)

Having four different modules, the Infrared Spectrograph operates to varying wavelengths of low and high resolutions. The short wavelength uses arsenic-doped silicon band technology, whereas the long wavelength used the antimony-doped silicon band technology.

Multiband Imaging Photometer for Spitzer (MIPS)

The Multiband Imaging Photometer has three detector sequences in the far IR region of the EMR spectrum. The 24-micrometer detector is similar to the one used in IRS short-wavelength modules. The 70 micrometer and the 160-micrometer sensors are gallium-doped germanium based detectors.

Some of the Missions of Spitzer Space Telescope

The Spitzer Space telescope has been very useful throughout the time it spent in space. Some of the incredible mission that is accomplished is the following:

Spitzer Beyond Mission

It began its observation cycle on October 1, 2016, and it went for a time period of 2 and a half years. The goals of the Spitzer Beyond mission included preparing for the James Webb Space Telescope that’s about to release in the coming year.

Planet Hunter Mission

Another successful mission of Spitzer was to study the exoplanets – that was made possible because of its amazingly on point hardware. The light changes in the hardware caused it to become more stable by changing its heating cycle. It did so by keeping the spacecraft’s cooling system to as low as 29 K.

The Discoveries of Spitzer Space Telescope


It discovered the exoplanet HD 219134b in 2015, which has a rocky surface.

The Planets Around Star TRAPPIST-1

In October 2016, it discovered a total of seven planets around the star TRAPPIST-1.

Sizes and Masses of Planets

It measured the sizes, masses, and densities of seven different exoplanets.

Discovery of a Galaxy

The combined efforts of Spitzer and Hubble were able to discover a distant galaxy GN-z11.

The Verdict

The Space Telescopes are indeed a great way of looking and observing into space. All the discoveries and observations of Spitzer Space Telescopes are quite remarkable. It is the last of the 4 Great Observatories that NASA launched in the 1990s. However, a better version is yet to come. The James Webb Telescope is a successor of these observatories, and we are looking forward to getting much more detailed information about the outside world and the exoplanets. The Great Observatories have made it possible to detect celestial objects within different ranges of the electromagnetic spectrum.