The Spitzer Space Telescope is getting a second chance at life.
The liquid helium âlifebloodâ? that flows through the telescope has finally run out, bringing Spitzerâs primary mission to an end. But a new phase of this infrared telescopeâs exploration of the universe is just beginning.
Even without liquid helium, which cooled the telescope to about 2 degrees above absolute zero (-271Â°C), Spitzer will continue to do important researchâsome of which couldnât easily be done during its primary mission. For example, scientists will use Spitzerâs âsecond lifeâ? to explore the rate of expansion of the universe, study variable stars, and search for near-Earth asteroids that could pose a threat to our planet.
âWe always knew that a âwarm phaseâ of the mission was a possibility, but it became ever more exciting scientifically as we started to plan for it seriously,â? says JPLâs Michael Werner, Project Scientist for Spitzer. âSpitzer is just going on and on like the Energizer bunny.â?
Launched in August 2003 as the last of NASAâs four Great Observatories, Spitzer specializes in observing infrared light, which is invisible to normal, optical telescopes.
That gives Spitzer the power to see relatively dark, cool objects such as planet-forming discs or nearby asteroids. These objects are too cold to emit light at visible wavelengths, but theyâre still warm enough to emit infrared light.
In fact, all warm objects âglowâ? with infrared lightâeven telescopes. Thatâs why Spitzer had to be cooled with liquid helium to such a low temperature. Otherwise, it would be blinded by its own infrared glow.
As the helium expires, Spitzer will warm to about 30 degrees above absolute zero (â243Â°C). At that temperature, the telescope will begin emitting long-wavelength infrared light, but two of its short-wavelength sensors will still work perfectly.
And with more telescope time available for the remaining sensors, mission managers can more easily schedule new research proposals designed for those sensors. For example, scientists have recently realized how to use infrared observations to improve our measurements of the rate of expansion of the universe. And interest in tracking near-Earth objects has grown in recent yearsâa task for which Spitzer is well suited.
âScience has progressed, and people always have new ideas,â? Werner says. In its second life, Spitzer will help turn those ideas into new discoveries.
For kids, The Space Place Web site has a fun typing game using Spitzer and infrared astronomy words. Check it out at spaceplace.nasa.gov/en/kids/spitzer/signs.
This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
The âwarm missionâ? of the Spitzer Space Telescope will still be able to use two sensors in its Infrared Array Camera (IRAC) to continue its observations of the infrared universe.