NASA's DART spacecraft sets sight on target asteroid, beams back image before collision

NASA’s DART (Double Asteroid Redirection Test) spacecraft has beamed back the first picture of its target asteroid before it rams into it on September 27. The spacecraft is heading for an intentional collision with Dimorphos, an asteroid moonlet orbiting a bigger asteroid named Didymos. Launched on November 24 last year, the objective of DART is to test whether an asteroid’s path can be changed artificially, an idea that could prevent Earth from massive space rocks capable of causing mass extinction. 

Taking to Twitter, NASA provided an update about the mission and shared a picture of the Didymos asteroid seen as a tiny, illuminated dot. The agency explained that the picture is a composite of 243 images taken by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) on July 27 this year. 

"This first set of images is being used as a test to prove our imaging techniques", Elena Adams, the DART mission systems engineer at the Johns Hopkins Applied Physics Laboratory (APL) said in a statement. "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". 

According to NASA, the collision will take place at 4:44 am IST on September 27 (7:14 EDT on Sept 26) and the mission team would execute three trajectory correction maneuvers over the next three weeks to reduce the margin of error. On September 26, i.e just a day before the impact, a final maneuver will be carried out and the team will know the position of the target Dimorphos within 2 kilometers. Beyond the said distance, the spacecraft will head autonomously toward Dimorphos for a collision. 

What happens after the impact?

After the impact, the European Space Agency (ESA) will launch its Hera mission in 2024. The Hera spacecraft will release two small CubeSats that would conduct close-up investigations of the aftermath. The first CubeSat named Milani will carry out spectral measurements of Dimorphos's dust whereas Juventas will perform the first radar probe of an asteroid. ESA says that Hera's main objective is to gather key information such as the size of DART’s crater, the mass of Dimorphos, and its make-up and internal structure.