In a world first, NASA has crashed a spacecraft into an asteroid in an attempt to get the rocky traveler off its trajectory. The Double Asteroid Redirection Test or DART is designed to cover a broad spectrum of procedures that might prevent an asteroid from colliding with Earth. David Barnhart, a professor of astronautics at the University of Southern California, is the director of the Space Engineering Research Center there. He has been able to see NASA''s live stream of the successful mission and
IMPACT SUCCESS! Watch from #DRACO Camera, a vending machine-sized spacecraft, successfully collides with the asteroid Dimorphos, which is the size of a football stadium and poses no threat to Earth. pic.twitter.com/7bXipPkjWD
1. What are the pictures?
The first photographs taken by a camera aboard DART show Didymos'' double asteroid system about 2,500 feet (780 meters) in diameter being orbited by Dimorphos, a smaller asteroid that measures 525 feet (160 meters).
The craft was shifted off after the DART targeting algorithm was lost on Dimorphos, and it began fleeing towards the smaller of the two asteroids. The image taken at 11 seconds before the impact and 42 miles (68 kilometers) from Dimorphos shows the asteroid centered in the camera''s field of view. This meant that the targeting algorithm was fairly accurate and the craft would collide right at the center of Dimorphos.
The second-to-last image, taken two seconds before impact, shows Dimorphos'' rocky surface, including small shadows. These shadows are interesting because they suggest that the camera aboard the DART spacecraft was directly seeing Dimorphos on, but the Sun was at an angle relative to the camera. They also suggest that the DART spacecraft was focused on its trajectory to impact Dimorphos at the moment, but it''s also possible that the asteroid was slowly rotating relative to the camera.
The final image, taken one second before impact, only shows the top slice of an image, but this is incredibly exciting. The fact that NASA received only one component of the image implies that the shutter took the picture, but DART, who was traveling at around 14,000 miles per hour (2,500 kilometers per hour) was unable to transmit the entire image before impact.
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2. What was supposed to happen?
The goal of the DART project was to see if an asteroid with a kinetic impact by plunging something into it. Before the test, Dimorphos orbited Didymos in about 16 hours. Although relatively small, a nudge like this might be enough to deflect a future asteroid.
3. What do we already know?
The last bits of data that was collected from the DART spacecraft right before impact indicate that it was on course. However, the fact that the images stopped transmitting after the target point was reached can only indicate that the impact was a success.
While there is likely to be a lot of information to be gained from DART''s images, the world will have to wait to see if the deflection was successful. Fifteen days before the impact, DART released a small satellite with a camera that was designed to document the entire impact. However, given that the small satellite does not have a large antenna onboard, the images will be slowly returned to Earth, one by one, in the coming weeks.
4. What does the test mean for planetary defense?
This study, according to me, was a great proof-of-concept for many technologies that the US government has invested in over the years. And importantly, it proves that it is possible to deploy a craft to intercept with a tiny target millions of miles away from Earth. DART has been a great success.
Over the next months and years, researchers will learn how much deflection the impact had, and how much may be measured and, most importantly, whether this type of kinetic impact may actually stifle a celestial object a bit at a large enough distance to prevent a future asteroid from posing threats to Earth.