Chinese Chang’E 2 Spacecraft Captures Toutatis

Chang’E 2 Images of Asteroid Toutatis on 13 December 2012 Image Credit: Weibo.com/Xinhuashidian Emily Lakdawalla, at the Planetary Society, published these stunning images of the asteroid Toutatis (captured by The Chinese spacecraft Chang’E 2) as it tumbled past the Earth on 12 and 13 December 2012. Chang’E 2 was originally launched on 1 October 2010, and mapped the Moon during an eight month mission. China published these high resolution images of the Moon earlier this year. Now, Chang’E 2 has become the first spacecraft to reach the Sun-Earth Lagrange point (SEL-2) from lunar orbit. It departed lunar orbit in June of 2011. The world was caught completely off-guard by this low profile fly-by of the asteroid Toutatis. At closest approach, Chang’E 2 was 3.2 kilometers above the surface of the asteroid. The images were taken from a distance of 93 and 240 kilometers. China becomes the fourth country to observe an asteroid, after US, the European Union and Japan. In January, Chang’E 2 will reach a distance of 10 million kilometers from Earth. Additional details have been published by Xinhua on their website, and at Discovery.com. In August, Bill Gray at the Planetary Society, published an update on the Chnag’E 2 mission. Paolo, a member of the UnmannedSpaceflight.com forum, reported in October concerning a paper he had obtained from the IAF Congress entitled “Low energy trajectory optimization for CE-2’s extended mission after 2012“. He did share these items from the paper: 13 December 2012 is confirmed as the date. no distance nor relative speed or other details are given we are told that the Beijing Aerospace Control Center called for proposals on a mission beyond L2 in January 2012 there were lots of interesting proposals including one that would flyby Earth and Moon repeatedly, visit the L1 and L2 Lagrangian points, flyby a hundred-meter sized asteroid and finally explore the L4 Sun-Earth point in 2017 (the paper states that CE-2 would have been the first mission to do so. I think one of the two Stereos was first) in March 2012 the Toutatis flyby, proposed by the Chinese Academy of Space Technology was selected in a non-optimized form, the mission would have cost 107.5 m/s of the remaining 120 m/s delta-v budget a 6.2 m/s correction on 15 April “was mainly used to keep the Lissajous trajectory”. it was previously reported as the date CE-2 was maneuvered out of the L2 halo orbit trajectory optimization was only carried out starting on 16 April. After optimization, an additional 22 m/s delta-v was gained that could be used to ensure a successful flyby the first targeting maneuver was carried out on 31 May (32.9 m/s) the second targeting maneuver (46.5 m/s) was to be carried out on 24 September Sky and Telescope has also weighed in with unique information on the fly-by. The passage was so close that the deflection in the trajectory of the spacecraft could be used to determine the gravitational mass of Toutatis, which in turn would yield the overall density, a key to understanding its bulk composition and internal makeup. edited: 5 PM 16 December 2012