When DART hits its asteroid target, we’ll see nothing.
Instead, the stream of images of the small asteroid Dimorphos gets bigger and bigger as the DART spacecraft approaches and it will freeze closer.
Then, if he wins, the engineers will cheer. There is no such thing as disconnecting connections to confirm a successful failure.
This final image, which will be taken about two and a half seconds before the collision, with the asteroid’s surface filling the camera’s field of view, is the last we’ll see of Demorphos on Monday night.
However, it will not be the last photo.
Behind DART is a small spacecraft called the Light Italian CubeSat for Asteroid Imaging, or LICIACube. Built by the Italian Space Agency, LICIACube was tagged with DART for the first nine months of the mission, then they separated and went their own way down a slightly altered path that Demorphos will miss.
LICIACube will capture images of the DART demise as well as the resulting crater. But due to its small size—and its antenna is small, too—it will only be able to send data slowly over a weak radio signal to radio dishes in NASA’s Deep Space Network. It will likely take a day or two before the first LICIACube images are available.
About 40 telescopes on Earth and many in space will also be pointed at Dimorphos and the main asteroid, Didymos, before and after the collision. None of them can see Dimorphos, let alone the split that would result from DART.
But expectations are that the Didymus-Demorphos system will get brighter in the hours after the collision.
Thomas Statler said, “What we’re looking for there is an overall brightness of the entire system, which indicates how much dust and other debris has been kicked up as this projectile travels into space, as it is illuminated by the sun.” The scientist of the DART program, during a press conference last week.
Dr. Statler said that how much and how quickly the bleaching occurs “is a measure of something about the consistency of the material that has been raised and how much.”
Telescopes include NASA Hubble And the James Webb Space Telescopes And the camera is on Lucy spacecraft Which is heading towards a date with asteroids trapped in the orbit of Jupiter. Lucy Mission started About a month before I do DART.
Hubble will not be able to see Didymus at the time of impact because Earth will be in the way. Instead, the telescope will begin observing after about 15 minutes. “That’s fine because we don’t really expect anything that is really observable from the exact moment of impact,” Dr. Statler said.
It’s not clear if the Webb Telescope, which spends most of its time staring at galaxies billions of miles away, can track a small, fast-paced asteroid less than seven million miles from Earth.
“Let me stress here, that’s not what JWST was designed to do,” said Nancy Chabot, a planetary scientist at Johns Hopkins University in Baltimore who serves as coordination lead for the DART mission, during a press conference on September 12. “This is a difficult measurement for them.”
She said, however, that it is worth a try.
“This is a unique opportunity in a unique moment to take all the resources we can to maximize what we are learning,” said Dr. Chabot, “so they are looking. We will see what they get.”
The primary measurement will be the change in the time it takes Dimorphos to complete an orbit around Didymos. A direct collapse of the DART will drain some of the angular momentum of the Dimorphos, causing it to fall close to Didymos. This is expected to speed up Demorphos and shorten its orbital period, which is currently 11 hours 55 minutes, by about 1 percent.
“We’ll notice that the binary asteroid system is running fast,” Dr. Statler said.
This measurement, with radar and periodic dimming as Dimorphos pass in front of or behind Didymos, will take some time.
“I would be surprised if we had a consistent measurement of period change in less than a few days,” Dr. Statler said. “And I’d be really surprised if it took more than three weeks.”
