A NASA spacecraft will soon make history when it crashes into an asteroid in the world’s first planetary defense test.
The Double Asteroid Redirection Test, or DART asteroid mission, will slam a spacecraft into the tiny moon of asteroid Gemini in Monday, September 26with impact set to 7:14 p.m. EDT (2314 GMT). If all goes well, the spacecraft will hit the moon, called Dimorphos, and take images right up to the moment of impact. You will be able to see these images live in real time. Read on for a handy guide to when it all happens.
But first, some science. NASA’s DART mission launched nearly a year ago on November 24, 2021 to test the use of a “kinetic impactor” to change the trajectory of an asteroid — the first planetary defense test of its kind.
Related: 8 Ways to Stop an Asteroid: Nuclear Weapons and Bruce Willis?
The DART Dimorphos target is about 560 feet (170 meters) wide and orbits its larger parent Gemini once every 11 hours and 55 minutes. The asteroids are about 7 million miles (9.6 million kilometers) from Earth and pose no risk of hitting our planet, NASA said. DART should hit Dimorphos while traveling at about 14,760 mph (23,760 km/h). Here’s what the final day of DART will look like.
Sunday, September 25: A day for the DART asteroid impact
While the stage was set for NASA’s DART asteroid impact with its 2021 launch, the space rock impact action is really starting to heat up in the last 24 hours. That’s when DART will perform its final maneuver to put it on its path to impact Gemini.
“After the final maneuver on September 25, approximately 24 hours before impact, the navigation team will know the position of the Dimorphos target within 2 kilometers [1.2 miles]NASA officials wrote in a statement (opens in new tab). “From there, DART will be on its own to guide itself autonomously on its collision course with the asteroid’s moon.”
Related: Why did NASA choose Gemini for the asteroid crash mission?
Monday, September 26: 4 p.m. ET — The final phase of DART begins
About four hours before impact, the DART spacecraft will enter what scientists call “the final phase.” The spacecraft’s DRACO camera should be locked to the asteroid Gemini and looking for its moon Dimorphos.
“At that point, at four o’clock, we’re actually targeting Gemini because we can’t see Dimorph,” said Evan Smith, DART’s associate mission systems engineer at the Johns Hopkins University Applied Physics Laboratory (JHUAPL) in Laurel, Maryland. .
During the terminal phase, DART flight controllers will no longer issue ground commands. The spacecraft will be fully autonomous in targeting using its intelligent navigation system, Smith said.
Monday, September 26: 5:30 p.m. ET — DART asteroid camera views
At 5:30 p.m. EDT (2130 GMT), NASA will begin transmitting a stream of real-time photos from DART’s Draco camera. This is the camera that will show the asteroids Gemini and Dimorphos as they grow in DART’s field of view.
“In the hours before the impact, the screen will appear mostly black, with a single point of light. This spot is the Didymos binary asteroid system, which consists of a larger asteroid called Gemini and a smaller orbiting asteroid called Dimorphos,” NASA wrote in a description of the video (opens in new tab).
The images in this stream will be slightly delayed due to the time it takes for the signal to reach Earth from DART at a distance of 7 million miles (11 million km) and then be processed on the ground. NASA has already released a view of Gemini from DART, as well as a view of Jupiter and its moons.
“After the impact, the feed will go black – due to signal loss. After about 2 minutes, this feed will turn into a replay – showing the final moments leading up to the impact,” NASA wrote.
Monday, September 26: 6 p.m. ET — The NASA DART webcast begins
NASA’s live webcast of the DART asteroid impact will begin Monday at 6 p.m. EDT (2200 GMT).
NASA has said that this stream will have the raw, most up-to-date images of the asteroid impact as it happens. The webcast will be streamed by JHUAPL, which oversees the mission for NASA.
September 26: 6:24 p.m. ET — 50 minutes before impact
About 50 minutes before DART hits Dimorphos, the spacecraft should finally shift its focus to the smaller moon.
“At 50 minutes after impact, we will have seen Dimorph for maybe 40 minutes,” Smith said, adding that both the moon and its parent Gemini should be in the spacecraft’s camera. “Both objects will still be in the field of view, but we will go straight for Dimorphos and go for an impact there.”
September 26: 6:54 p.m. ET — DART precision lock on Dimorphos
At 6:54 p.m. EDT (2254 GMT), DART will be just 20 minutes away from crashing into Dimorphos, and its intelligent navigation system will enter what’s called a “precision lock.”
“In the 20 minutes before impact, we go into something called a precision lock, where we completely ignore Gemini and go straight for Dimorphus only,” Smith said. “We expect to be under quite a bit of pressure during that period.”
September 26: 7:11 p.m. EDT — DART cuts its engines
Shortly after 7:11 p.m. EDT (2311 GMT), DART will shut down its ion engines and prepare for the inevitable. The spacecraft will then be on a collision course with Dimorphos at a speed of 14,760 mph (23,760 km/h).
“Two and a half minutes before impact, we cut off all thrust and we’re headed,” Smith said. “We’ll be streaming images all the time.”
September 26: 7:14 p.m. ET — DART hits asteroid Dimorphos
This is the big moment! If the DART hits the mark, then the Dimorphos live views from the DRACO camera will be cut off.
Elena Adams, DART’s chief mission systems engineer at JHUAPL, said there is a 91% to 99% chance of a successful impact if DART’s cameras can see Dimorphos.
The impact should set off a huge plume of ejections that should be seen by a small cube called the LICIACube. The cubesat hitched a ride with DART on launch and blasted off a few weeks ago.
September 26: 7:17 p.m. ET — LICIACube passes by Dimorphos
Three minutes after the DART hits the Dimorphos LICACube should fly away from the impact point.
LICIACube will take pictures of the resulting ejecta plume created by DART’s crash and then send them back to Earth. The images will likely be released on September 28, as it takes time for the small planet to emit them, NASA said.
LICIACube (short for “Light Italian Cubesat for Imaging Asteroids”) was built by the Italian Space Agency and launched by DART on September 11.
“We expect to receive the first full-frame images and process them a few days after the DART impact,” Simone Pirrotta, LICIACube project manager for the Italian Space Agency, said in a statement. (opens in new tab).
September 26: 8 p.m. ET — NASA DART post-impact update
At 8 p.m. EDT (0000 GMT on September 27), NASA will hold a press conference to discuss the DART asteroid impact.
While we don’t have a list of people attending the press conference, you can be sure it will be packed with mission managers and JHUAPL and NASA officials hoping to celebrate DART’s success. The press conference will be broadcast live on NASA TV.
You can watch the press briefing on the DART asteroid impact webcast page.
And this is a look at when DART will drop into the asteroid Dimorphos and how the day will play out.
Visit Space.com on Monday, September 26 for complete coverage of NASA’s DART asteroid mission.
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