NASA’s DART spacecraft was 6.8 million miles from Earth when it slammed into an asteroid the size of a football stadium on Monday. Despite this immense distance, images of the impact and its aftermath are coming in, and they’re proving to be better, and far stranger, than we expected.
Going into Monday’s test, it wasn’t clear how much of the double asteroid redirection test we’d see. At the very least, we hoped to get the POV experience of DART’s on-board camera, called DRACO, and views from the shoebox-sized LICIACube, which was far behind the spacecraft condemned by NASA. They did not disappoint.
We also knew that telescopic eyes would be watching from afar, including ground-based observatories and two rather famous space telescopes, Hubble and Webb. Again, they did not disappoint.
It’s still early in terms of data collection, but the combined result is that we’re getting a reasonably clear picture of what happened when DART hit Dimorphos. This is great in terms of getting the public involved in what is a very important mission to deflect an asteroid, but also in terms of the science needed to find out if it actually worked.
Didymos and Dimorphos
Image: NASA/Johns Hopkins APL
The gravitationally linked pair are separated by just 3,960 feet (1,200 meters). Didymos, which measured 807.72 m wide (780 meters), was discovered in 1996 and its moon Dimorphos, which measured 158.50 m wide (160 meters), was seen seven years later. We really had no idea what these tiny objects looked like given the vast distances involved, but DART’s high-resolution DRACO instrument revealed the pair in exquisite detail.
The image above was taken 2.5 minutes before impact and at a distance of 920 kilometers (570 miles) to the target asteroid. With DRACO capturing one image per second and DART moving at 22,531 km per hour (22,500 km/h), this is the last image to show both objects in a single frame.
A jumble of rocks
Image: NASA/Johns Hopkins APL
This, the last complete image of Dimorphos, was taken when DART was 7 miles (12 km) away and 2 seconds before impact. The image revealed Dimorphos to be an egg-shaped “debris pile,” an asteroid loosely held together by loose conglomerations of debris, including bits of asteroids and broken moons.
Brace yourself for the impact
Image: NASA/Johns Hopkins APL
This small patch of Dimorphos is where DART finally found its destination, and is the last complete frame produced by the probe. It’s fair to say that this patch no longer looks that way, with the 624kg probe plowing right into its target. The resulting kinetic impact, it is expected, altered the speed and orbital path of the asteroid around Didymos. Ultimately, the experiment could produce an effective planetary defense strategy against dangerous near-Earth objects.
A key goal of the LICIACube mission was to capture post-impact images of Dimorphos. The European Space Agency’s upcoming HERA mission will also attempt to collect images of the impact’s effect on the asteroid.
When signal loss is good
Image: NASA/Johns Hopkins APL
DART was in the process of transmitting its next DRACO frame when it finally crashed to the surface. This final image provided our first visual confirmation that the spacecraft was no longer among the living and that DART had, with pinpoint accuracy, reached its target after a 10-month journey.
The final five minutes
This stabilized time lapse of the DART experiment shows the last five and a half minutes of the test in just 30 seconds. The video was created by Germany’s Spei’s Space News YouTube channel.
From a safe distance
Image: ASI/NASA
This stunning view of the impact was captured by LICIACube, which was within 35 miles (55 km) of Dimorphos at the time. DART sent the Italian-built probe about two weeks ago and used its two onboard cameras, LUKE and LEIA, to capture images of the impact and the effect it had on the asteroid. The bright object in the foreground is Didymos.
Wow, what great streamers you have
Image: ASI/NASA
An unusually large and complex plume emerged from the asteroid as a result of the collision. “I’m shocked by the streamers in the ejecta [the material tossed up by the impact],” tweeted University of Central Florida planetary scientist Phil Metzger. In regular laboratory impact splash experiments to simulate asteroid impacts “we don’t see anything like that,” he added.
Great boom of the sea
Image: ASI/NASA
Another view of the impact, as imaged by LICIACube, short for Light Italian Cubesat for Imaging Asteroids. The 31-pound (14-kilogram) probe, Italy’s first deep-space spacecraft, used an autonomous tracker to keep its two cameras locked on the target asteroid.
A lot to learn
Image: ASI/NASA
The strangeness of the impact plume will be of great interest to scientists, who will no doubt study it in great detail. The resulting insights will shed important new light on the asteroid, such as its composition and volume. LICIACube took about 600 images during the encounter, which is currently in the process of being linked to Earth. In fact, these four images are just the beginning, as the probe made a close flyby of Dimorphos to investigate a possible impact crater and capture images of its opposite side.
The view from Earth
Image: Gianluca Masi (Virtual Telescope Project, Italy) and Berto Monard (Klein Karoo Observatory, South Africa)
This series of images shows the progression of the impact plume in the 20 minutes after impact. It was taken from the Klein Karoo Observatory in South Africa, in collaboration with Italy’s Virtual Telescope Project. From this distance, the binary asteroid system appears as a single point in telescopic images.
A clearly perceptible plume of impact
This video of the plume was captured by astronomers at the Les Makes Observatory in Le Reunion, a French island in the Indian Ocean. “Something like this had never been done before, and we weren’t quite sure what to expect,” Marco Micheli, an astronomer at ESA’s Coordination Center for Near-Earth Objects, said in a press release . “It was an emotional moment for us when the pictures came in.” At the time of impact, Didymos was only visible to observatories in the southern hemisphere.
View of the ATLAS
Gif: Project ATLAS/Gizmodo
The animation above was put together by astronomers with the ATLAS project in Hawaii. Ground-based images consistently showed a growing plume moving in the direction of the asteroid. The binary star system is so far away that its light takes 38 seconds to reach Earth.
A popup queue
Image: E. Guido, M. Rocchetto, G. Savini, S. Fossey, Telescope Live
Italian amateur astronomer Ernesto Guido and colleagues used a 0.6-meter telescope operated by the Telescope Live Observatory in Chile to capture this light curve image (which shows the intensity of an object’s light) about 29 hours after impact. A tail or plume is now visible in the Didymos-Dimorphos system, which may eventually wrap around to form a ring.
The view from space… at a distance
Image: James Webb Space Telescope
Several space telescopes were tuned for the encounter, namely Hubble, Webb and a camera mounted on NASA’s Lucy probe currently en route to Jupiter’s Trojan asteroids. We’re still waiting for those images to become available, but a preliminary image of Webb (above) is likely to be the first of many. The Webb telescope, which operates from the second Sun-Earth Lagrange point, was approximately 6 million miles (9.7 million km) from Didymos at the time.