Mem. S.A.It. Vol. 83, 393 c SAIt 2012 Memorie della The Hubble Space Telescope: 21 years and counting N. Panagia1;2;3 1 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 2 Istituto Nazionale di Astrofisica – Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy 3 Supernova Ltd, OYV #131, Northsound Road, Virgin Gorda, British Virgin Islands e-mail:
[email protected] Abstract. I summarize the current status of the Hubble Space Telescope (HST) and illus- trate some of its exciting results. Key words. Telescopes: HST – Cosmology: observations – Dark Matter – Early Universe – Galaxies: Magellanic Clouds – Stellar Populations – Stars: V838 Mon – Planetary System – Comet: SL9 – Planets and Satellites: Pluto 1. Introduction After SM3B, HST’s science instruments in- cluded a spectrograph, the Space Telescope After twenty one years in orbit, the now “adult” Imaging Spectrograph (STIS) operating in the Hubble Space Telescope (HST) continues to UV and optical domains, and three cam- play a major role in astronomical research, and eras, the Wide Field - Planetary Camera 2 is undoubtedly one of the most important and (WFPC2), the Advanced Camera for Surveys most prolific space astronomy missions of all (ACS), the Near Infrared Camera - Multiobject time. Spectrograph (NICMOS), which was revived HST was deployed in low-Earth orbit in mission 3B with the installation of a (about 600 km) by the crew of the space mechanical cooling system, and the Fine shuttle Discovery (STS-31) on 25 April 1990. Guidance Sensors (FGS, primarily used for as- Although at the beginning the mission looked trometric observations).