一级做a免费观看大全视频,中文字幕乱码无限2019,日日麻批40分钟免费视频播放,精品专区性色av,国产性夜夜春夜夜爽,岛国三级片免费看久久,久久五月天和激情网

NASA to knock asteroid off orbit for first time in 2022

Source: Xinhua| 2019-01-23 18:44:26|Editor: xuxin
Video PlayerClose

LOS ANGELES, Jan. 23 (Xinhua) -- NASA will remove an asteroid from its orbit for the first time in 2022 with its Double Asteroid Redirection Test (DART) spacecraft.

The asteroid, called Didymoon, is a moon asteroid around 150 meters tall belonging to the double asteroid system Didymos. Didymos is the most accessible asteroid of its size from Earth.

The DART spacecraft will be NASA's first attempt to demonstrate what is known as the kinetic impactor technique which will strike the asteroid to shift its orbit to defend against a potential future asteroid impact, according to a statement by Lindley Johnson, planetary defense officer at NASA Headquarters in Washington.

NASA said the DART spacecraft will achieve the kinetic impact by deliberately crashing itself into the asteroid at a speed of approximately 6 km/s. It also said the collision will change the speed of the moonlet in its orbit around the main body by a fraction of 1 percent, enough to be measured using telescopes on Earth.

The spacecraft will be launched between December 2020 and May 2021.

TOP STORIES
EDITOR’S CHOICE
MOST VIEWED
EXPLORE XINHUANET
010020070750000000000000011100001377685301


一级做a免费观看大全视频,中文字幕乱码无限2019,日日麻批40分钟免费视频播放,精品专区性色av,国产性夜夜春夜夜爽,岛国三级片免费看久久,久久五月天和激情网 国产视频观看91 国产00在线视频国产 国产综合色视频久久久 久久成人国产精品一区二区 高清无码免费黄色网站