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 crash a spacecraft into the small moon of asteroid Didymos in Monday, September 26with impact set at 19:14 EDT (23:14 GMT). If all goes well, the spacecraft will collide with the small moon, called Dimorphos, and take images up to the moment of impact. You will be able to see those live images in real time. Read on for a handy guide to when it will all happen.
But first, some science. NASA’s DART mission launched almost a year ago, on November 24, 2021, to test the use of a “kinetic impactor” to change the orbit of an asteroid, the first planetary defense test of its kind.
Related: 8 Ways to Stop an Asteroid: Nuclear Weapons and Bruce Willis?
DART’s target, Dimorphos, is about 560 feet (170 meters) across and orbits its larger parent, Didymos, once every 11 hours and 55 minutes. The asteroids are about 9.6 million kilometers (7 million miles) from Earth and pose no risk of impacting our planet, NASA said. DART should hit Dimorphos while traveling at about 14,760 mph (23,760 kph). This is what the last day of DART will look like.
Sunday, September 25: A day for the impact of the asteroid DART
While the stage has been set for NASA’s DART asteroid impact with its launch in 2021, the space rock impact action really starts to heat up in the last 24 hours. That’s when DART will perform its final maneuver to put you on course for a Didymos impact.
“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 a new tab). “From there, DART will be on its own to guide itself autonomously to its collision with the asteroid’s small moon.”
Related: Why did NASA choose Didymos for its asteroid strike mission?
Monday, September 26: 4 p.m. ET: DART Terminal Phase Begins
About four hours before impact, the DART spacecraft will enter what mission scientists call its “terminal phase.” The spacecraft’s DRACO camera is to lock onto the asteroid Didymos and search for its moon Dimorphos.
“At that point, at four hours, we’re actually targeting Didymos because we can’t see Dimorphos,” said Evan Smith, DART deputy mission systems engineer at Johns Hopkins University Applied Physics Laboratory (JHUAPL). in Laurel, Maryland.
During the terminal phase, DART flight controllers will no longer issue commands on the ground. The spacecraft will be completely autonomously oriented using its intelligent navigation system, Smith said.
Monday, September 26: 5:30 pm ET — Asteroid DART Camera Views
At 5:30 pm EDT (21:30 GMT), NASA will begin streaming a real-time sequence of photos from DART’s Draco camera. This is the camera that will show the Didymos and Dimorphos asteroids as they grow in DART’s field of view.
“In the hours before impact, the screen will appear mostly black, with a single point of light. That point is the binary Didymos asteroid system, which is made up of a larger asteroid called Didymos and a smaller asteroid orbiting around it called Dimorphos.” NASA wrote in a description of the video. (opens in a 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 7 million miles (11 million km) away, and are then processed on the ground. NASA has already released a view of Didymos from DART, as well as a view of Jupiter and its moons.
“After impact, the feed will go black, due to a loss of signal. After approximately 2 minutes, this feed will turn into a replay, showing the final moments before impact,” NASA wrote.
Monday, September 26: 6 pm ET — NASA DART webcast begins
NASA’s live webcast of the DART asteroid impact will begin Monday at 6 pm EDT (2200 GMT).
NASA has said that it is this broadcast that will have the most up-to-date, raw images of the asteroid impact as it happens. The webcast will be run from JHUAPL, which oversees the mission for NASA.
September 26: 6:24 pm ET — 50 minutes before impact
About 50 minutes before DART hits Dimorphos, the spacecraft should change its target to the little moon at last.
“Within 50 minutes of impact, we will have been seeing Dimorphos for about 40 minutes,” Smith said, adding that both the small moon and its parent Didymos should be in view of the spacecraft’s camera. “Both objects will still be in the field of view, but we’re going to go directly to Dimorphos and hit there.”
September 26: 6:54 pm ET: DART precision lock on Dimorphos
At 6:54 pm EDT (22:54 GMT), DART will be just 20 minutes away from crashing into Dimorphos and its intelligent navigation system will enter what is called a “precision lock.”
“20 minutes before impact, we go into something called a precision lock, where we completely ignore Didymos and go straight to just Dimorphos,” Smith said. “We expect to be pushing quite a bit in that period.”
September 26: 7:11 p.m. EDT — DART turns off its engines
Just after 7:11 pm EDT (23:11 GMT), DART will shut down its ion engines and prepare for the inevitable. The spacecraft will then be on track to crash into Dimorphos at 14,760 mph (23,760 kph).
“Two and a half minutes before impact, we cut off all thrust and we’re going in,” Smith said. “We’re going to be transmitting images all the time.”
September 26: 7:14 pm ET — DART hits asteroid Dimorphos
This is the big moment! If the DART hits the target, that is when the live views of Dimorphos from the DRACO camera will be cut off.
Elena Adams, DART’s principal 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 kick up a huge plume of ejected material that should be seen by a small cubesat called LICIACube. The cubesat traveled with DART during launch and was ejected a few weeks ago.
September 26: 7:17 pm ET — LICIACube flies over Dimorphos
Three minutes after DART hits Dimorphos, LICIACube should fly past the impact site.
LICIACube will take photos of the resulting ejection plume created by the DART crash and then send them back to Earth. The images are likely to be released on September 28, as it takes time for the little cubesat to send them back, NASA said.
LICIACube (short for “Light Italian Cubesat for Imaging Asteroids”) was built by the Italian Space Agency and was launched by DART on September 11.
“We expect to receive the first full-frame images and process them a couple of days after the DART impact,” Simone Pirrotta, LICIACube project manager for the Italian Space Agency, said in a statement. (opens in a new tab).
September 26: 8 pm ET — NASA DART post-impact briefing
At 8 pm EDT (0000 GMT on September 27), NASA will hold a press conference to discuss the impact of the asteroid DART.
While we don’t have a list of who will attend the press conference, rest assured it will be filled with mission managers and officials from JHUAPL and NASA hoping to celebrate DART’s success. The press conference will be broadcast live on NASA TV.
You can view the press conference on our DART asteroid impact webcasts page.
And that’s a look at the time DART will crash into asteroid Dimorphos and how the day will unfold.
Visit Space.com on Monday, September 26 for full coverage of NASA’s DART asteroid mission.
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