“This is the first time we’ve actually tried to move something in our solar system with the aim of preventing [potential] Statler said.
DART probe, short for Double asteroid navigation testoperational since 2015. It is designed, built, and operated by the Johns Hopkins University Applied Physics Laboratory, with support from multiple NASA centers, and released last November. DART is a major part of AIDA, Asteroid Deflection and Impact Assessment, a collaboration between NASA and the European Space Agency. The mission also depends on observatories in Arizona, New Mexico, Chile, and elsewhere; Astronomers are keeping their telescopes focused on Dimorphos and Didymos to measure post-collision deflections as accurately as possible.
Until the end of DART’s flight, astronomers could only see Dimorphos and Didymos as a single bright dot. The smaller asteroid is so small it can’t be seen from Earth telescopes – but astronomers can track it by measuring how often it dims the already faint light from its larger brother of it as it orbits it.
The ship’s final approach was captured by its optical camera, known as the DRACO, which is similar to the onboard camera. New horizons, was flown by Pluto. Even this close-up camera could only see the Dimorphos as a separate object a few hours before impact.
“Because you’re coming so quickly, in the last few minutes we’ll see what the Dimorphos look like: What’s the shape of the asteroid we’ve never seen before?” Nancy Chabot, a planetary scientist at Johns Hopkins University and DART’s co-ordinator, said in an interview days before the collision. “Really in just the last 30 seconds, we’ll be resolving surface features on the asteroid.”
In fact, to this day, scientists are not really sure whether this asteroid will look like a billiard ball or a dust ball. “Is this moon a single giant rock, or is it a collection of pebbles or grains? We don’t know,” Carolyn Ernst, a JHU researcher and DRACO tool scientist, said ahead of the impact. Its composition could affect a number of factors scientists want to study: How much the impact will change the asteroid’s orbit, if it will leave a crater, rotating the asteroid planets or eject pieces of rock.
Unlike most space probes, DART does not slow down before reaching its target. As it approaches, its camera continuously takes pictures of the asteroid as it grows in the frame, sending them to Earth via the Deep Space Network, an international antenna system run by the Propulsion Laboratory. Jets managed by NASA.
Those images aren’t just important for research; they are the key to navigation. It takes 38 seconds for the operator to send a signal to the DART — or for the probe to send an image back to Earth. When the moment is critical, the probe needs to be self-driving. Over the past 20 minutes, its automated SMART Nav system performed a “precision lock” on the target and used these images to adjust the spacecraft’s course with its propulsion.
