• Launch date: 25 August 2005
• Agency: NASA
Considered a cousin of the Hubble Space Telescope, the Spitzer Space Telescope is designed to study the early universe in infrared light. The first telescope to see light from a planet outside our solar system, Spitzer has also made important discoveries about comets, stars, exoplanets and distant galaxies.
In 2009, Spitzer ran out of liquid coolant and began its “warm mission,” refocusing its studies on determining how quickly our universe is stretching apart, and characterizing asteroids and the atmospheres of gas-giant planets.