NASA’s tiny spacecraft approached the tiny asteroid on Monday, heading for a self-destructive 14,000mph head-on collision, the world’s first test of humanity’s ability to push a threatening body off course before it collides with Earth.

The asteroid in question, a 500-foot-wide body known as Dimorphos, is actually a moon orbiting a 2,500-foot wide asteroid named Didymos. None of them pose any threat to the Earth, either before or after the impact of NASA’s 1,260 pound space probe (Double Asteroid Redirection Test) or DART.

An artistic vision of NASA’s DART spacecraft heading for a collision of 14,000 miles per hour with a small 525-foot-wide asteroid known as Dimorphos. The asteroid is actually a small moon orbiting a larger asteroid called Didymos. The $ 330 million mission is testing one of the asteroid or comet redirection techniques on a collision course with Earth.


However, the dual asteroid system makes an ideal target for the $ 330 million DART mission, as the effects of the probe impact can be measured from Earth by precisely measuring the changes in the orbital period of the moon around Didymos as a result of the collision.

By uploading Dimorphos images once per second, the DART spacecraft should give scientists an exciting view from the deck as the spacecraft rushes towards its quarry, showing the target getting bigger and bigger until it fills the entire field of view seconds before impact.

“Two and a half minutes before the impact, SMART Nav, the autonomous algorithms that brought us to this point, will shut down and we’ll just point the camera and take the most amazing pictures of this asteroid,” said Elena Adams, DART Systems Engineer at the Physics Laboratory Applied Johns Hopkins University.

NASA plans to stream live images to YouTube, and coverage of the mission will begin at 6 p.m. EST. The impact is expected at 19:14, and streaming images from the spacecraft every second will begin a few minutes earlier.

Dimorphos and Didymos to scale with familiar landmarks on Earth.


Dimorphos has never been directly observed, and the DART camera will not detect it as a separate body from Didymos until an hour before impact, at a distance of approximately 15,000 miles. At this point, it will appear as a light point only 1.4 pixels across. But it will quickly grow to 21 pixels before reaching 1,000 miles, just 4 minutes before it hits.

“Our last image will probably come from about two and a half seconds before impact,” Adams said. “So the field of view of DRACO (the camera) will actually be completely filled with this beautiful picture of Dimorphos.”

The transmissions will cease upon impact. But since the collision will occur 7 million miles from Earth, the last few photos will take about 45 seconds to cross the chasm and hit computers and NASA live streaming.

“You will hear that we have lost radio contact and there will still be images that will appear once a second for about eight seconds,” said Edward Reynolds, DART Project Manager at APL.

“These are images that travel in space. They hit the ground, we detected we lost radio contact, but these images are still working in the pipeline and are being displayed. “

A small Italian hitchhiker known as LICIACube, released from DART earlier this month, will attempt to photograph the collision and debris being thrown back into space. These images will be stored on board and later linked to Earth.

The Didymos-Dimorphos double asteroid system offers an ideal stand for testing planetary defense, as the moon’s orbit carries it directly in front of and then behind Didymos when viewed from Earth, enabling scientists on Earth to precisely measure small changes in the combined light reflected from both asteroids.

The white trace shows the current orbit of the target asteroid Dimorphos for 11 hours and 55 minutes, while the blue line shows how the orbit could be altered by the impact force of the DART probe at 14,000 miles per hour. Scientists say the collision could shorten the orbital period by about 10 minutes.


By determining the time to dim and brighten the light, the scientists calculated how long Dimorphos took to complete one orbit – 11 hours and 55 minutes – and post-impact observations will allow them to determine what effect DART may have had.

Scientists expect the catastrophe will shorten the orbital period of the asteroid by about 10 minutes, but telescopes around the world and in space, including the Hubble and James Webb space observatories, may take days to weeks to take the measurements needed for the touchdown. number.

“The asteroid double-redirection test is a test,” said Tom Statler, DART program scientist. “We do this test when we don’t have to, on an asteroid that is not dangerous, in case we ever have to and discover an asteroid that is dangerous.”

He said the DART mission has two main goals, the first of which is to test “our ability to build an autonomously guided spacecraft that will actually achieve a kinetic effect on an asteroid.”

“The second is a test of how an actual asteroid responds to a kinetic impact,” he said. “Because, in the end, the real question is how successfully we moved the asteroid and could this kinetic impact technique be used in the future if ever needed?”

Unlike Hollywood thrillers such as “Armageddon” and “Deep Impact,” which imagined piloted planes carrying atomic b*mbs to deflect or destroy their targets, the DART target is much simpler and much less destructive.

While nuclear devices may be the last resort in some future Armageddon-class scenario, the goal will still be deflection, not destruction.

“You just don’t want to blow it up because it doesn’t change the direction of all the stuff,” Lindley Johnson, NASA’s Planetary Defense Officer told CBS News ahead of the DART launch last November. “Still flying at you, it’s just pellets instead of a rifle bullet.”

“You just want to slightly change the speed at which it all moves. Over time, this will change the position of the asteroid and its orbit. “

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