Space is full of fast-moving bits of rock called “micrometeoroids,” which routinely and unavoidably smack into spacecraft in orbit. It was tiny, smaller than a grain of sand-less than a few tenths of a millimeter-but even tiny things travel at astounding speeds out in space.Įveryone on the Webb project knew something like this would happen to the telescope after it launched in December. That week, a particle of dust struck one of Webb’s mirrors. Unfortunately, the universe doesn’t care if you’re out of the office. “This was my big trip to go and finally relax,” Feinberg told me. It was supposed to be his first vacation in 20 years that wouldn’t get interrupted by the James Webb Space Telescope. So when the work was done, and the process had unfolded beautifully, Feinberg went to Spain with his wife and two children. The success of the ambitious observatory, designed to capture the sharpest images of the most distant stars and galaxies, depended on it. It was late May, and Feinberg, a manager at NASA’s Goddard Space Flight Center, had spent “an incredibly tense several months” leading the effort to carefully deploy the mirrors on the world’s newest and most powerful space telescope, making sure that each of the gold-coated tiles-18 in all, arranged in a honeycomb shape-was properly aligned. Using observations taken every five hours, the DART team will execute three trajectory correction manoeuvres over the next three weeks, each of which will further reduce the margin of error for the spacecraft's required trajectory to impact.Īfter the final manoeuvre on 25 September, approximately 24 hours before impact, the navigation team will know the position of the target Dimorphos within two kilometres.įrom there, DART will be on its own to autonomously guide itself to its collision with the asteroid moonlet.Lee Feinberg was on vacation, and he deserved it. "In September, we'll refine where DART is aiming by getting a more precise determination of Didymos' location." "Seeing the DRACO images of Didymos for the first time, we can iron out the best settings for DRACO and fine-tune the software," said Julie Bellerose, the DART navigation lead at Nasa's Jet Propulsion Laboratory in Pasadena, California. Read more: Telescope detects 100 mysterious radio signals from billions of light years away "The quality of the image is similar to what we could obtain from ground-based telescopes, but it is important to show that DRACO is working properly and can see its target to make any adjustments needed before we begin using the images to guide the spacecraft into the asteroid autonomously."Īlthough the team has already conducted a number of navigation simulations using non-DRACO images of Didymos, DART will ultimately depend on its ability to see and process images of Didymos and Dimorphos, once it too can be seen, to guide the spacecraft toward the asteroid, especially in the final four hours before impact.Īt that point, DART will need to self-navigate to impact successfully with Dimorphos without any human intervention. "This first set of images is being used as a test to prove our imaging techniques," said Elena Adams, the DART mission systems engineer at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. It will hit the smaller rock at 3.7 miles per second, and Nasa scientists will monitor to see what effect it has on the 530ft rock's flight path.įrom this distance – about 20 million miles away from DART – the Didymos system is still very faint, and navigation camera experts had been uncertain whether the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) would be able to spot the asteroid yet.īut once the 243 images DRACO took during this observation sequence were combined, the team was able to enhance it to reveal Didymos and pinpoint its location. The spacecraft will ram the moonlet Didymos B, which orbits around a larger asteroid Didymos A. Read more: What are fast radio bursts, and why do they look like aliens? The idea is that the fridge-sized DART spacecraft will hit Didymos, an asteroid with an orbiting moonlet, faster than a bullet – and change its orbit. Nasa's Double Asteroid Redirection Test ( DART) spacecraft recently had a first look at its target. The mission, due to take place on 26 September, marks the first step towards a solution – the ability to knock potential doomsday asteroids onto less-threatening flight paths – if an asteroid is hurtling towards Earth. Nasa will crash a spacecraft into an asteroid on purpose later this month – to see what happens next. Nasa's DART spacecraft imaged its target this week with its onboard camera.
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