All good things must come to an end. This includes NASA’s Spitzer Space Telescope, an infrared observatory orbiting Earth. The telescope, which has been in operation for 16 years, has captured data on exoplanets, far-off galaxies and unknown mysteries of the universe. After an illustrious career, Spitzer is set to retire on Jan. 30. Here are some highlights from Spitzer’s journey:Aug. 25, 2003Spitzer data allows scientists to see light from the earliest stars (and, possibly, black holes). After capturing images of the Milky Way for five years, NASA reveals a comprehensive portrait of our home galaxy. GLIMPSE, as the imaging project was known — short for Galactic Legacy Infrared Mid-Plane Survey Extraordinaire — measures 180 feet by 4 feet when printed at full resolution. This panoramic image from GLIMPSE shows a lot of stellar activity in the Milky Way’s plane. The image spans 9° of sky (by 2° tall), about as much as the width of your fist held at arm’s length. This region represents only 7.5 percent of the GLIMPSE survey, which imaged most of the star-forming regions in our galaxy. The red clouds show the presence of large molecules illuminated by nearby stars. (Credit: NASA/JPL-Caltech/E. Churchwell (University of Wisconsin)) May 19, 2009 The telescope’s coolant, essential for helping reduce heat noise in images, runs out, officially ending Spitzer’s “cold mission.” Two of Spitzer’s instruments, the Infrared Spectrograph and the Multiband Imaging Photometer, become officially unusable. This begins the “warm” phase of Spitzer’s mission. Spitzer discovers an unknown ring around Saturn, called the Phoebe ring. The ring, also the planet’s largest by radius, was only discovered because of Spitzer’s infrared capabilities. An artist’s illustration shows the grand scale of the Phoebe ring. (Credit: NASA/JPL-Caltech/Keck) An artist’s impression of the star TRAPPIST-1, as seen from above one of the newly-discovered exoplanets. (Credit: ESO/M. Kornmesser)Spitzer is supposed to end its mission, but due to delays on the James Webb Space Telescope, Spitzer continues until 2020. This begins Spitzer’s “Beyond” mission. Jan. 28, 2020Jan. 30, 2020