WEBVTT FILE 1 00:00:00.000 --> 00:00:04.990 ​​Launched in 1990, NASA’s Hubble Space Telescope has investigated some of the most 2 00:00:04.990 --> 00:00:07.520 compelling mysteries of the universe. 3 00:00:07.520 --> 00:00:12.219 Technology advanced in the seven years after Hubble’s launch, offering NASA the opportunity 4 00:00:12.219 --> 00:00:17.580 to upgrade Hubble during its Second Servicing Mission in February 1997. 5 00:00:17.580 --> 00:00:22.260 During five spacewalks, astronauts installed the Space Telescope Imaging Spectrograph, 6 00:00:22.260 --> 00:00:26.820 or STIS, a new versatile tool for studying visible and ultraviolet light. 7 00:00:26.820 --> 00:00:32.180 They also added the Near-Infrared Camera and Multi-Object Spectrometer, or NICMOS, which 8 00:00:32.180 --> 00:00:36.740 allowed researchers to gaze further from Earth and farther back in time than ever before 9 00:00:36.740 --> 00:00:39.920 thanks to its infrared-detecting capabilities. 10 00:00:39.920 --> 00:00:43.850 Along with the new instruments, astronauts equipped the telescope with a refurbished 11 00:00:43.850 --> 00:00:48.580 fine guidance sensor and a new data recorder, replaced its gyroscopes and solar arrays, 12 00:00:48.580 --> 00:00:51.500 and repaired its damaged insulation. 13 00:00:51.500 --> 00:00:56.330 These activities extended Hubble's lifetime, while STIS and NICMOS expanded humanity’s 14 00:00:56.330 --> 00:00:58.930 view of the universe.