Nasa DART mission - as it happened: Nasa successfully smashes spacecraft into asteroid in first major test
Nasa completes the first-ever planetary defence mission, an attempt to change the course of an asteroid by hitting it with a spacecraft
Sign up to our free weekly IndyTech newsletter delivered straight to your inbox
Sign up to our free IndyTech newsletter
Nasa‘s asteroid-deflecting DART spacecraft successfully slammed into its target on Monday, 10 months after launch.
The test of the world’s first planetary defense system will determine how prepared we are to prevent a doomsday collision with Earth.
The cube-shaped “impactor” vehicle, roughly the size of a vending machine with two rectangular solar arrays, flew into the asteroid Dimorphos, about as large as a football stadium, and self-destructed around 7.14pm EDT (11pm GMT) some 6.8 million miles (11 million km) from Earth.
The mission’s finale tested the ability of a spacecraft to alter an asteroid’s trajectory with sheer kinetic force, plowing into the object at high speed to nudge it astray just enough to keep our planet out of harm’s way.
It will be the first time humanity has changed the motion of an asteroid, or any celestial body. Nasa has a live stream of the event, which you can find at the top of our live blog below.
Autonomous mode
Nasa’s Dart spacecraft is moments away from transitioning to full autonomous navigation, relying on the computer algorithms that will guide Dart the rest of the way on its terminal mission to smash into the asteroid Dimorphos.
“We’re about six minutes away from transitioning to autonomous mode in terms of navigation,” Robert Braun told reporters at a press event at the John Hopkins Applied Physics Laboratory around 3.10pm EDT Monday afternoon. APL and Jet Propulsion Laboratory enginers have been managing the Dart mission for Nasa — and guiding the spacecraft — in the months since it launched in November, 2021.
Nasa and APL will be providing updates and background to the media throughout the afternoon and into the early evening ahead of the Dart impact, which is expected at 7.14pm EDT.
Goosebumps
Robert Braun told reporters Monday afternoon that when thinking about the Dart mission this morning, it gave him goosebumps — it’s the first time humans will try to change the course of a celestial object.
“Proving the technology to deflect an asteroid,” he said, “that’s something of importance to the entire Earth.”
The mission is also different than most other missions APL has been involved in with Nasa, Braun said. When you’re landing on Mars, for instance, you’re waiting and hoping for a first signal from the lander, and maybe some images.
“Here what we’re waiting for is a loss of signal,” he said. “Here what were cheering for is the loss of the spacecraft.”
Confidence of Dart’s success is high, but there could be uneexpected holes in the plan
Nasa will know by 7.14pm EDT if the Dart mission was successful in striking the asteroid Dimporphos around 6.8 million miles from Earth.
The world can watch the lead up however, as Nasa TV has begun showing images taken the Dart spacecraft’s navigational camera, known as Draco, according to Robert Braun, the head of the space exploration sector at the Johns Hopkins Applied Physics Laboratory (APL), which manages the Dart mission for Nasa.
“What you will see are images coming back from Draco on a 1 per second cycle,” Braun told reporters at APL Monday afternoon. “It will get bigger and bigger in the field of view, and I would suspect the last image may even be a partial image.”
That partial image would be due to the high velocity of Dart, which will strike Dimorphos at 14,400 miles per hour.
And it almost certainly will hit Dimorphos, barring some very unusual circumstances, according to Braun — since Dimporphos is too small to see clearly from Earth, it could hold some surprises yet.
“There are all kinds of crazy scenarios. We don’t know the shape of what we’re goin to hit right now,” Braun told reporters. “Ao if we we’re right on course bu it was shipped like a doughnut, we might fly right through it. But that’s unlikley.”
All eyes on Dart on Dimorphos Monday
Nasa’s Dart mission is about to attempt the unprecedented in moving a celestial object, the asteroid Dimorphos. But hitting that asteroid is just the first part of the mission, according to Nasa’s Associate Administrator for Science Thomas Zurbuchen.
The Hubble Space Telescope, The James Webb Space Telescope, and the Lucy spacecraft, a Nasa mission to the asteroids near Jupiter, will all be focusing on Dimorphos when Dart slams into the asteroid around 7.14pm EDT Monday, Dr Zurbuchen told reporters at the Johns Hopkins Applied Physics Laboratory Monday afternoon.
“The question is will they see a brightening of that object,” he said. “That comes from ejecting dust and having that be hit by the Sun and therefore changing the brightness.”
The images will not be particularly large or clear, Dr Zurbuchen added.
“Just think of the size of these objects, they are minuscule,” he said. “Like seeing a football stadium from many millions of miles away, so that is what we are trying to do.”
Additional views
Even as the big Hubble and and James Webb Space Telescopes turn their massive mirrors on the asteroid Dimporphos ahead of Nasa’s Dart impact test Monday evening, there are other, smaller eyes tracking the asteroid.
The Italian space agency’s Light Italian CubeSat for Imaging of Asteroids, or LiciaCube, hitched a ride to Dimorphos on Dart before separating from Nasa’s spacecraft on 11 September. The microwave sized satellite is now following about three minutes behind Dart and will be positioned to observe Dart’s impact on Dimorphos from a safe distance.
Those image likely won’t be available for a day or two, Nancy Chabot told reporters at the Johns Hopkins Applied Physics Laboratory Monday afternoon. Dr Chabot is the a planetary scientist and Dart mission coordination lead at APL.
What LiciaCube will be looking for, she said, are the materials thrown out and away from Dimophos when Dart stikes the asteroid at more than 14,000 miles per hour, materials known as ejecta.
“That is one of main reasons to do the Dart test, is to see how much ejecta,” Dr Chabot said. “This isn’t just billiard balls.”
No one really knows how much ejecta will be generated, because no one has gotten a close up look at Dimorphos, which is about the size of the Great Pyramid of Giza — large for a person, but very tiny when 6.8 million miles from Earth. Depending on what the asteroid is made of and its consistency, there could be more or less material thrown off by Dart’s impact.
One thing is for certain however, Dr Chabot told reporters, in the combat between Dart and Dimorphos,” the spacecraft will lose.”
The origin of the Dart mission
Monday’s Dart mission has its origins in the exercise habits of Andy Cheng, chief scientist for planetary defense at the Johns Hopkins Applied Physics Laboratory (APL).
“I conceived of the mission that would become Dart in my basement,” Dr Cheng told reporters at APL Monday afternoon. “In early 2011, I was doing some exercises, stretches, in my basement ... and I had on my mind, ‘we should really do a planetary defense mission. It’s time.”
But it wasn’t the notion of planetary defense missions that was unique or new, it was Cheng’s recipe for conducting it.
European scientists in 2004 conducted a detailed study of a potential mission to study the change in an asteroids orbit around the Sun after striking it with a kinetic impactor like Dart. But that required a second space craft, Dr Cheng said — one craft to hit the asteroid, and another to watch.
“It cost too much,” and never got off the ground, he said.
Dr Cheng’s new idea was to target a binary asteroid system. A change in the orbit of a smaller asteroid around a larger one is much easier to detect that the subtle change in an asteroid’s much larger orbit around the Sun, and could even be observed by ground-based telescopes, obviating the need for an expensive second spacecraft.
“That idea stuck, and I took it to Nasa,” Dr Cheng said.
Asteroid Radar
While ground based telescopes and space based telescopes will be monitoring the Dart spacecraft’s impact of the asteroid Dimorphos at 7.14pm EDT Monday evening, scientists will won’t just be monitoring in optical wavelengths. Radar will play an important role, and may make the definitive measurements that tell scientists just how much Dart changes the orbit of its asteroid target.
“Radar is extremely precise,” Northern Arizona University Planetary Scientist Cristina Thomas told reporters at a Monday afternoon press event at the Johns Hopkins Applied Physics Laboratory. “We know right now, to a very high level, exactly where Dimorphos should be. So if you send that radar ping out and it’s not where it should be, that should tell you about that shift in position.”
Radar observations could detect a change in Dimorphos’s orbit within a day or two, Dr Thomas added. That change could be very small at first, but will grow over time, and the small asteroids orbit around its larger companion could ultimately shift as much as 10 minutes.
Dimorphos currently takes an hour and 55 minutes to complete one orbit.
One radio telescope that will not participate in the Dart mission is the now defunct Arecibo radio telescope in Puerto Rico; the telescope was decommissioned following irreparable damage after Hurricane Maria crashed through the US territory.
“Arecibo was planned to be used [for Dart],” APL planetary scientists and APL Coordination Lead for the Dart mission Nancy Chabot said. “The loss of Arecibo is still felt in the community.”
How to watch Dart
Nasa’s Dart space craft is getting closer to its date with destiny — the refrigerator sized spacecraft will slam into the small asteroid Dimorphos at 7.14pm EDT Monday, not much more than an hour from now.
You can actually see Dimorphos and its larger companion asteroid, Didymos, as a single point of light in the feed from Dart’s camera. Nasa is maintaining a live feed from the camera on the space agency’s media channel, and the image should update about once a second right up to the moment Dart crashes into the asteroid.
Beginning at 6pm EDT, NASA TV will begin carrying a broadcast with commentary on the mission that will last through the moment of truth at 7.14 p.m.
The Independent will keep you updated on this blog as the mission draws closer to its terminal destination.
Nasa Dart broadcast is now live
Nasa has begun its broadcast covering its Dart mission to “alter the orbit of an asteroid, forever.”
You can tune in on Nasa TV at www.nasa.gov/nasalive.
Could Dart deflect an asteroid threatening Earth?
Dart is targeting Dimorphos, a small asteroid about 500 feet across that does not threaten Earth and will not, even after it’s orbit is altered by Dart’s crashing into it Monday evening.
“The closest this asteroid will ever get to Earth is 4 million miles,” Northern Arizona University Planetary Scientist Cristina Thomas told reporters at a Monday afternoon press event at the Johns Hopkins Applied Physics Laboratory.
Dart is designed to test the concept of a “kinetic impactor,” an experiment to see if a Dart-like spacecraft could be built in the future to deflect an asteroid that threatened our planet.
But if Dimorphos, or an asteroid like were threatening Earth, would Dart itself be capable of diverting it? After all, Dart is “essentially a very heavy vending machine,” Dr Thomas said, “that is about to collide with , essentially the Great Pyramid of Giza.”
“We do think something like Dart would be big enough to deflect a Dimophos-sized object,” APL Dart impact modeling working group lead Angela Stickle told reporters Monday afternoon, “If we had a few years notice.”
Despite the size difference between Dart and its target, Dart is moving very fast, and, Dr Stickle said, it doesn’t take a massive one-time blow to change an asteroid’s orbit.
“In space, little pushes can add up to a lot,” she said. “The push we give it will be enough to change its orbit by 10 minutes.”
Subscribe to Independent Premium to bookmark this article
Want to bookmark your favourite articles and stories to read or reference later? Start your Independent Premium subscription today.
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies
Comments