Asteroid impact prediction

Current systems only detect an arriving object when several factors are just right, mainly the direction of approach relative to the Sun, the weather, and phase of the Moon.In 1992 a report to NASA recommended a coordinated survey (christened Spaceguard) to discover, verify and provide follow-up observations for Earth-crossing asteroids.[4] In 1998, NASA formally embraced the goal of finding and cataloging, by 2008, 90% of all near-Earth objects (NEOs) with diameters of 1 km or larger that could represent a collision risk to Earth.[3] The impact of an object much larger than 1 km diameter could well result in worldwide damage up to, and potentially including, extinction of the human race.However, the 2009 discovery of several NEOs approximately 2 to 3 kilometers in diameter (e.g. 2009 CR2, 2009 HC82, 2009 KJ, 2009 MS and 2009 OG) demonstrated there were still large objects to be detected.Three years later, in 2012, the 40 meter diameter asteroid 367943 Duende was discovered and successfully predicted to be on close but non-colliding approach to Earth again just 11 months later.It injured 1,500 people and damaged over 7,000 buildings, raising the profile of the dangers of even small asteroid impacts if they occur over populated areas."[5] Also in 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet.Cataloging systems focus on finding larger asteroids years in advance and they scan the sky slowly (of the order of once per month), but deeply.They typically cannot detect objects that are as faint as cataloging systems but they will not miss an asteroid that dramatically brightens for just a few days when it passes very close to Earth.This long period of warning is important as an impact from a 1 km object would cause worldwide damage and a minimum of around a decade of lead time would be needed to deflect it away from Earth.Current mechanisms for detecting asteroids on approach rely on ground based visible-light telescopes with wide fields of view.Moreover, as the hours of darkness are fewer in summertime, the lack of a balance of surveys between North and South meant that the sky was scanned less often in the Northern summer.The Cassegrain reflector telescope takes three to four weeks to survey the entire sky, detecting objects fainter than apparent magnitude 21.5.[33] In late 2019 the Kiso Observatory added a new instrument to the telescope, "Tomo-e Gozen", designed to detect fast moving and rapidly changing objects.In order to scan the sky so quickly, the camera captures 2 frames per second, which means the sensitivity is lower than other metre class telescopes (which have much longer exposure times), giving a limiting magnitude of just 18.[39] The telescope will use a passive cooling system, and so unlike its predecessor NEOWISE, it will not suffer from a performance degradation due to running out of coolant.[22][23] The Near Earth Object Survey TELescope (NEOSTEL) is an ESA funded project, starting with an initial prototype currently under construction.The telescope is of a new "fly-eye" design that combines a single reflector with multiple sets of optics and CCDs, giving a very wide field of view (around 45 square degrees).On 6 December 2013, it was announced that the telescope system would be moved to the Naval Communication Station Harold E. Holt in Exmouth, Western Australia.The International Astronomical Union Minor Planet Center (MPC) acts as the global clearing house for information on asteroid orbits.For example, the Great Shefford Observatory in the back garden of amateur Peter Birtwhistle typically submits thousands of observations to the Minor Planet Center every year.There are plans for a new space based thermal infrared survey telescope, Near-Earth Object Surveillance Mission, due to launch in 2025.[70] NASA's Sentry System continually scans the MPC catalog of known asteroids, analyzing their orbits for any possible future impacts.In December 2004 when Apophis was estimated to have a 2.7% chance of impacting Earth on 13 April 2029, the uncertainty region for this asteroid had shrunk to 82,818 km.She thought it prudent to take precautionary measures by ordering her students to stay away from the room's windows and to perform a duck and cover maneuver.[75][76] If the impact had been predicted and a warning had been given to the entire population, similar simple precautionary actions could have vastly reduced the number of injuries.[77] If a more severe impact is predicted, the response may require evacuation of the area, or with sufficient lead time available, an avoidance mission to repel the asteroid.By contrast, missing a large day-side impacting asteroid is highly problematic, with the unpredicted mid-size Chelyabinsk meteor providing a mild real-life example.As the telescope will be a long way from Earth for most of the year (and even behind the Sun at some points) communication would often be slow and at times impossible, without expensive improvements to the Deep Space Network.