NASA is two weeks away from intentionally crashing a spacecraft into an asteroid, and scientists think the images sent back by 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 Didymos, the double-asteroid system that includes its target, Dimorphos.
An image taken from 20 million miles away showed the Didymos system as quite faint. Still, once a series of images taken by Didymos Reconnaissance and the Asteroid Camera for Optical navigation (DRACO) were combined, astronomers were able to pinpoint the exact location of Dimorphos.
DART’s camera continues to send back images of Didymos while sending images to the spacecraft’s algorithm to steer the spacecraft as it approaches the tiny moon. It uses a navigation system called Small-body Maneuvering Autonomous Real-Time Navigation or SMART Nav to guide itself.
“We’re getting to four miles per second, so we can’t sit there with our controller and our joystick and steer it,” Andy Rivkin, a planetary astronomer at the Johns Hopkins Applied Physics Laboratory, said of the navigation system. “The camera will take images. It will send them to the computer. The computer will say, ‘Okay, we need to go a little bit to the left. We need to go a little bit to the right,’ and it will take us inside and then it also sends those images back to Earth.” “.
About 8 hours before impact, the team hands over control to the SMART Nav system while “patting it on the head and giving it good luck,” Rivkin said.
In the final hours, DART selects the impact site and heads down. It will continue to send images until it can no longer do so.
“It will start out as a small point of light, and then eventually it will zoom in and fill the entire field of view of the images that come back. You will be able to see things that can be centimeters of pixel, and these images will continue until they stop. So which will be a pretty definitive look at the final moments of the DART spacecraft,” said DART Coordinating Director Nancy Chabot.
Scientists say DART’s success will ultimately depend on its ability to view and process images of Didymos and Dimorphos to guide the spacecraft toward the asteroid, especially in the last four hours before impact. At that point, DART must navigate itself to successfully impact Dimorphos without any human intervention.
“These images come back to Earth one per second, and the plan is to broadcast them live on NASA’s television feed. And like I said, they’re going to be pretty impressive,” Chabot explained.
And once the impact happens, scientists will use ground-based and satellite telescopes to see if their plan worked.
Satellite the size of a toaster to send images
On Sunday, DART deployed a small Italian Space Agency satellite called LICIACube to record the collision and its aftermath.
LICIACUbe is about the size of a cereal box and has two cameras nicknamed after “Star Wars” characters: LUKE (LICIACube Unit Key Explorer) and LEIA (LICIACube Explorer Imaging for Asteroid).
LICIACube will fly past Dimorphos about three minutes after DART’s disappearance to capture images of the effects of the impact.
“I’m really excited that it’s out there and flying because we want to see some amazing images, some of the latest images of stars right there from that little CubeSat. That’s technology that about 10 or 15 years ago seemed crazy to be used in that context,” NASA associate administrator Thomas Zurbuchen said Monday.
looking from afar
Meanwhile, the James Webb and Hubble Space Telescopes will observe the asteroid system and measure the change in Dimorphos’s orbit around Didymos.
Once DART hits Dimorphos, it will change its orbit within the binary system. The DART research team will compare the results of DART’s kinetic impact on Dimorphos with highly detailed computer simulations of kinetic effects on asteroids.
After the impact, the research team will measure how much the asteroid is deflected using telescopes on Earth.
Telescopic observations, images captured by DRACO, images of the LICIACube impact, and data later collected by the European Space Agency’s Hera mission will help scientists build more accurate models to better prepare for a future discovery. asteroid impact threat.
NASA plans to host live coverage of DART’s impact with asteroid Dimorphos on its website and social media channels.