Two minutes and 460 miles (740 km) closer, DART had made its final maneuvers and was drifting at 14,000 miles per hour (22,000 k/ph) to its end. At that point, DRACO could only resolve its target as a 1.5-pixel-wide dot (Didymos, by comparison, appeared 7 pixels wide).įour minutes out, at a distance of 920 miles (1,500 km), Dimorphos had grown in size to 22 pixels wide. It was not until the spacecraft was 14,000 miles (22,000 km) away - an hour out from impact - did Dimorphos become observable. Even at that distance, though, the two asteroids appeared as one. (NASA)ĭART's navigation camera, DRACO (or Didymos Reconnaissance and Asteroid Camera for Optical Navigation) did not get its first look at its destination until four hours before it impacted, when it was still 56,000 miles (90,000 km) from the binary asteroid system. Click to enlarge video in a new pop-up window. We don't know what it looks like, we don't know what the shape is, and that's just one of the things that leads to the technical challenges of DART," said Statler.ĭART's approach to Dimorphos. Targeting, let alone hitting, an asteroid that is about the same size as one of the pyramids in Egypt at a distance of about 7 million miles (11 million km) from Earth is not easy. "At the end of the day the real question is, how effectively did we move the asteroid?" "We're doing this test when we don't need to, on an asteroid that isn't a danger, just in case we ever do need to and we discover an asteroid that is a danger," said Tom Statler, NASA program scientist for the DART mission, in a press conference previewing the impact. Were a rocky body of similar size to Dimorphos (which is 525 feet or 160 meters in diameter) be found on a collision course with Earth, the agency could launch a DART-like spacecraft to change its trajectory. If it was successful, the $330 million DART mission will serve as a model for one of the ways that NASA could protect Earth from an impending asteroid impact. " first test to help determine our response if we really do see an asteroid that's out there threatening to hit Earth." "Today we're taking a giant step in planetary defense, that is, protecting our home planet Earth," said NASA Administrator Bill Nelson in a video statement shared on the space agency's social media channels. Its impact marked the the first time that a spacecraft autonomously navigated to a target asteroid and intentionally collided with it in a try at changing the rock's motion in a way that could be measured by telescopes back on Earth. 26), ending its 10-month journey by crashing into Dimorphos, a "moonlet" of the asteroid Didymos. The Double Asteroid Redirection Test (DART) completed its mission on Monday (Sept. The spacecraft's sacrifice was in not vain, though - its loss may someday help save life on Earth. A NASA robotic probe has slammed into an asteroid and been destroyed.
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