![]() On Tuesday, public figures were quick to congratulate Nasa on the success of the test, which cost $325m. The Dart spacecraft, launched last year and roughly the size of a vending machine, was destroyed when it slammed into the asteroid 7m miles away, at 14,000mph, Nasa said. Glaze noted, however, that if a future asteroid threatens Earth, work on deflection would need to start far in advance: with the Dart mission having caused only a 4.5% change in orbit time, “the more time we have for that little nudge … the better off we are”. Glaze said the minimum requirement for changing the orbital period was “really only 73 seconds”. “Dart is a test for defending Earth against potential asteroid or comet hazards,” the space agency said.ĭart altered the orbit of the Dimorphos asteroid by 32 minutes. It was the world’s first test of the kinetic impact mitigation technique, using a spacecraft to deflect an asteroid that poses no threat to Earth, and modifying the object’s orbit. In a statement following the test, Nasa said Dart “intentionally crashed into Dimorphos, the asteroid moonlet in the double-asteroid system of Didymos. “Since the full range of pre-impact predictions went, in extreme cases, from “nothing happens” to “completely destroy Dimorphos”, the half-hour change is not outside of predictions.” “Now that we have the result of the experiment, we can work backwards to see what range of possible starting points give us the sort of period change we saw,” he added. “There was a very large range in predictions on what might possibly happen precisely because we don’t know that much about the interior structure of asteroids,” he said. Professor Colin Snodgrass, an astronomer and member of the Dart mission science team at Edinburgh University, said the next step was to work out what the change in orbit says about the internal structure of Dimorphos. Before the collision, Nasa officials said that a change in the orbit of 73 seconds or more would be considered a success. The observations revealed that Dart’s impact altered the orbit of Dimorphos around the larger Didymos asteroid by about 32 minutes, shortening the 11 hour and 55-minute orbit to 11 hours and 23 minutes. It took days of observation to determine how much the impact altered the path of the 525ft asteroid around its companion, a much bigger rock. Two famous Nasa telescopes, Webb and Hubble, captured the moment the spacecraft collided with the moonlet asteroid on 26 September. Our team has been preparing for these observations for years as we worked to understand the pre-impact orbital period and this result is a testament to how prepared we were for this moment.” “I am constantly impressed by this team and the phenomenal observations that they were able to collect in the two weeks since the impact. “I am absolutely thrilled about today’s announcement of the orbital period change due to the Dart impact,” said Cristina Thomas, Dart’s principal investigator. We’re all here this afternoon because for the first time ever, humanity has changed the orbit of a planetary body.” Lori Glaze, director of Nasa’s planetary division, said: “Let’s all just take a moment to soak this in. The Nasa administrator, the former astronaut and Democratic Florida senator Bill Nelson, said: “We showed the world that Nasa is serious as a defender of this planet.” “This is huge feat, not only in achieving the first step in possibly being able to protect ourselves from future asteroid impacts,” but also for the amount of images and data collected internationally, Daniel Brown, an astronomer at Nottingham Trent University in England, said via email.Nasa hopes to be able to deflect any asteroid or comet that comes to pose a real threat to Earth. Launched last year, the vending machine-size Dart - short for Double Asteroid Redirection Test - was destroyed when it slammed into the asteroid 7 million miles (11 million kilometers) away at 14,000 mph (22,500 kph). ![]() “You’ve got to know they’re coming,” added Glaze. “We really need to also have that warning time for a technique like this to be effective,” said mission leader Nancy Chabot of Johns Hopkins University’s Applied Physics Laboratory, which built the spacecraft and managed the $325 million mission. Planetary defense experts prefer nudging a threatening asteroid or comet out of the way, given years or even decades of lead time, rather than blowing it up and creating multiple pieces that could rain down on Earth.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |