August and November 2020, respectively, the NSF announced the decision that they would decommission the telescope through controlled demolition, but that the other facilities on the Observatory would remain operational in the future. However, before the safe decommission of the telescope could occur, remaining support cables from one tower rapidly failed in the morning of December 1, 2020, causing the instrument platform to crash through the dish, shearing off the tops of the support towers, and partially damaging some of the other buildings, though there were no injuries. NSF has stated that it is still their intention to continue to have the other Observatory facilities operational as soon as possible and are looking at plans to rebuild a new telescope instrument in its place Several spacecraft orbiting the Moon, Mercury, Venus, Mars, and Saturn have carried radars for surface mapping; a ground-penetration radar was carried on the Mars Express mission. Radar systems on a number of aircraft and orbiting spacecraft have mapped the entire Earth for various purposes; on the Shuttle Radar Topography Mission, the entire planet was mapped at a 30-m resolution. The Jodrell Bank Observatory, an operation of the University of Manchester in Britain, was originally started by Bernard Lovell to be a radar astronomy facility. It initially used a war-surplus GL-II radar system operating at 71 MHz (4.2 m). The first observations were of ionized trails in the Geminids meteor shower during December 1945. While the facility soon evolved to become the third largest radio observatory in the world, some radar astronomy continued. The largest (250-ft or 76-m in diameter) of their three fully steerable radio telescopes became operational just in time to radar track Sputnik 1, the first artificial satellite, in October 1957. See also Cavity magnetron History of smart antennas Klystron List of German inventions and discoveries List of World War II electronic warfare equipment Secrets of Radar Museum References Further reading Blanchard, Yves, Le radar. 1904–2004 : Histoire d'un siècle d'innovations techniques et opérationnelles, éditions Ellipses,(in French) Bowen, E. G.; "The development of airborne radar in Great Britain 1935–1945", in Radar Development to 1945, ed. by Russell Burns; Peter Peregrinus, 1988, Bowen, E. G., Radar Days, Institute of Physics Publishing, Bristol, 1987, Bragg, Michael., RDF1 The Location of Aircraft by Radio Methods 1935–1945, Hawkhead Publishing, 1988, Brown, Jim, Radar – how it all began, Janus Pub., 1996, Brown, Louis, A Radar History of World