NASA is two weeks away from intentionally crashing a spacecraft into an asteroid, and scientists believe the visuals sent back from the impact will be worth the wait. On September 26, the Double Asteroid Redirect Test spacecraft, known as DART, will be used as a battering ram to crash into an asteroid not far from Earth. DART recently got its first look at Gemini, the binary asteroid system that includes its target, Dimorphos. This image of light from the asteroid Gemini and its orbiting moon Dimorpho is a composite of 243 images taken by the Gemini Recognition and Asteroid Navigation Optical Camera (DRACO) on July 27, 2022. (NASA JPL DART Navigation Team / FOX Weather) An image taken from 20 million miles away showed the Gemini system quite faint. However, once a series of images taken by Didymos Reconnaissance and the Asteroid Camera for Optical Navigation (DRACO) were combined, astronomers were able to pinpoint Dimorphos’ exact location. DART’s camera continues to send back images of Gemini as it feeds images into the spacecraft’s algorithm to guide the spacecraft as it moves closer to the Moon. It uses a navigation system called Small-body Maneuvering Autonomous Real-Time Navigation or SMART Nav to guide itself. NASA’S SPACECRAFT PREPARED TO PURPOSELY HIT ASTEROIDS TO HELP SAVE EARTH “We’re coming in at four miles a second, and so we can’t sit there with our controller and joystick and steer it,” Johns Hopkins Applied Physics Laboratory planetary astronomer Andy Rivkin said of the navigation system. “The camera will take images. It will send them to the computer. The computer will say, ‘OK, we need to go a little bit to the left. We have to go a little to the right’ and take us in and then send these images back to Earth’. About 8 hours before impact, the team hands over control to the SMART Nav system as they “hit it on the head and say good luck,” Rivkin said. Inside a clean room at Johns Hopkins APL, the DART spacecraft was transferred to a specialized shipping container headed across the country to Vandenberg Space Force Base near Lompoc, California, where DART is scheduled to launch starting in November. Credit: Johns Hopkins APL/Ed Whitman (Johns Hopkins APL) In the final hours, DART selects the impact point and heads down. It will keep sending back images until it can’t anymore. “It will start as a small point of light, and eventually it will zoom in and fill the entire field of view of the images coming back. You’ll be able to see things that might be centimeters of pixels, and those images will continue until they don’t . So it will be a pretty definitive look at the final moments of the DART spacecraft,” said DART coordination chief Nancy Chabot. Scientists say DART’s success will ultimately depend on its ability to see and process images of Gemini and Dimorph to guide the spacecraft toward the asteroid, especially in the last four hours before impact. At that point, the DART will need to self-navigate to successfully collide with Dimorphos without any human intervention. Infographic showing the sizes of the two asteroids in the Gemini system relative to some objects on Earth. Credit: NASA/Johns Hopkins APL (NASA/Johns Hopkins APL) “These images are coming back to Earth at one per second, and the plan is to broadcast them live on NASA’s telecast. And like I said, these are going to be pretty amazing,” Chabot explained. 7 THINGS TO KNOW ABOUT NASA’S DART MISSION And once the impact happens, scientists will use satellite and ground-based telescopes to see if their plan worked.
Satellite the size of a toaster to send images
DART team engineers lift and inspect the LICIACube CubeSat after it arrived at Johns Hopkins APL in August. Credit: Johns Hopkins APL/Ed Whitman (Johns Hopkins APL) On Sunday, DART deployed a tiny satellite from the Italian Space Agency called LICIACube to record the collision and its aftermath. The LICIACube is about the size of a cereal box and has two cameras named after “Star Wars” characters: LUKE (LICIACube Unit Key Explorer) and LEIA (LICIACube Explorer Imaging for Asteroid). LICIACube will then fly past Dimorphos about three minutes after DART’s death to capture images of the impact’s effects. “I’m very excited that it’s out there and flying because we want to see some amazing pictures, some of the latest pictures of the stars right there from this little CubeSat. This is a technology that 10, 15 years ago seemed crazy. It’s going to be used in this framework,” NASA associate Thomas Zurbuchen said Monday.
Watching from afar
Fourteen consecutive Arecibo radar images of the near-Earth asteroid Gemini and its moon taken in November 2003. (NASA) Meanwhile, the James Webb and Hubble space telescopes will observe the asteroid system and measure the change in Dimorphos’ orbit around Gemini. Once the DART hits Dimorphos, it will change its trajectory within the binary system. The DART Research Team will compare DART’s kinetic impact results with Dimorphos to highly detailed computer simulations of kinetic effects on asteroids. NASA CONNECTS SPACECRAFT TO ASTEROID IS PART OF GLOBAL PLAN TO SAVE EARTH After the impact, the research team will measure how much the asteroid is deflected using telescopes on Earth. Telescope observations, images taken by DRACO, images of the impact by LICIACube and data later collected by the European Space Agency’s Hera mission will help scientists create more accurate models to better prepare in case a future impact threat is discovered asteroids. The European Space Agency’s HERA spacecraft will observe the impact left behind by NASA’s DART spacecraft. NASA plans to provide live coverage of DART’s impact with asteroid Dimorphos on its website and social media channels.
