NASA is gearing up to practice saving Earth from killer asteroids with a new mission

NASA is gearing up to practice saving Earth from killer asteroids with a new mission

NASA is gearing up to practice saving Earth from killer asteroids with a new mission

An artist's illustration of NASA's Double Asteroid Redirection Test (DART) mission as it approaches asteroid Dimorphos (Nasa)

An artist’s illustration of NASA’s Double Asteroid Redirection Test (DART) mission as it approaches asteroid Dimorphos (Nasa)

The dinosaurs could only watch helplessly as an asteroid or a comet brought their reign on Earth to an end, as could countless fictional humans in Hollywood space rock doomsday fodder like “Don’t Look Up” or “Seeking a Friend for the End of the World.”

But accepting the inevitability of a planet showering asteroid impacts isn’t sitting well with Nasa, and on Monday the space agency is doing something about it — testing a technique to deflect dangerous asteroids away from Earth by hitting them with a fast-moving spacecraft.

“The ground systems are clear and the spacecraft is healthy and on track for an impact on Monday,” Edward Reynolds, of the Johns Hopkins Applied Physics Laboratory, APL, told reporters during a press conference Thursday about the test. “We have plenty of fuel, and we have plenty of power.”

APL manages the operations of the Dart – Double Asteroid Redirection Test – spacecraft for Nasa, and Mr Reynolds is the mission program manager. He will be at the APL Mission Operations Center in Laurel Maryland at 7:14 p.m. EDT Monday night when the 1,200-pound spacecraft slams into the small asteroid Dimorphos in an attempt to change its orbit slightly — the asteroid poses no threat to Earth.

It is a first mission of its kind, and an ambitious one at that.

“Dimorphos is just over 100 meters in diameter; it’s not very big. “We’re at 14,000 miles per hour, we’re approaching something we’ve never seen before,” Reynolds said. “That’s why the ‘T’ in Dart is ‘test.’

Dart is a proof-of-concept mission that could help scientists understand whether a scaled-up version of this “kinetic impactor” technique could deflect a larger asteroid or comet that threatens Earth, NASA’s Dart program scientist, Tom Statler, told reporters Thursday.

“There are two tests in Dart. The first test is the test of our ability to build an autonomously guided spacecraft that will actually achieve the kinetic impact on the asteroid,” he said. “The second test is the test of how the actual asteroid reacts to the kinetic impact. Because at the end of the day, the real question is, how effectively did we move the asteroid?”

Dimorphos is a small asteroid about 525 feet across that also orbits a larger asteroid, Didymos. This creates a perfect natural laboratory for Dart, according to Dr. Statler, as Dimorphos currently takes 11 hours and 55 minutes to complete one orbit around Didymos. Scientists expect the Dart impact could reduce the orbital period anywhere from 73 seconds to 10 minutes, assuming the mission is a success.

A successful mission would confirm scientists’ models of how asteroids like Dimorphos behave, Dr Statler added, and would give Nasa confidence in designing any future mission to deflect an actual threatening asteroid.

“On the other hand, if the asteroid reacts to the arrow impact in a way that’s completely unexpected,” he said, “it could actually send us back to rethink the extent to which kinetic impact is really generally useful.”

It won’t be long before Nasa and APL get an answer to that question, as Dart is rapidly approaching the Didymos and Dimorphos system.

“About 24 hours before impact, it will be all hands on deck,” APL Dart mission systems engineer Elena Adams told reporters Thursday. Although Dart will transition to fully autonomous flight four hours before impact, APL operators will be on hand to intervene if anything goes wrong, up to and including a miss by the small asteroid.

“We have 12 emergency situations and number 21 is ‘Masset impact’,” Dr Adams said. “We’ll start saving fuel and we’ll start looking for the items to come back to. So that’s the plan.”

Dart took its first image of the two asteroids in July, and what were tiny points of light will quickly grow in the field of view of the spacecraft’s Didymos Reconnaissance and Asteroid Camera for Optical Navigation, or Draco instrument, as Dart approaches. Dimorphos is so small, and Dart is traveling so fast, Dr. Adams said, that the asteroid will remain relatively small until the final moments before impact, giving scientists their first real look at the shape and texture of the asteroid.

“Our last image will probably be from about two and a half seconds before impact,” she said. “So Draco’s field of vision is actually going to be completely filled with this beautiful image of Dimorphos.”

Nasa will carry the Dart effect live in two different feeds. A quiet stream of images from Dart’s Draco camera, about one frame per second, will be available on NASA’s media channel starting at 5:30 p.m. EDT, while a broadcast with commentary and the Draco images can be seen on Nasa TV starting at 6:00 p.m. EDT.

Success in the first part of the test will be marked by the loss of radio contact with Dart after the final images and its impact with Dimorphos, and there will be celebration among the engineers at APL, but it only marks the beginning of the next half of the mission, Dr Statler said .

“The engineering team will celebrate, and the astronomers at that moment will say, ‘OK, time to work,'” he said.

That’s because a wide array of telescopes on the ground and in space will be watching Dimorphos for signs of Dart’s impact, and then continue to check the asteroid for signs that its orbit has actually changed.

First and foremost will be the Light Italian CubeSat for Imaging of Asteroids, or LiciaCube, a small satellite produced and operated by the Italian space agency that went on a Dart farewell trip on September 11. It will be able to register the impact and any resulting material ejected from Dimorphos.

“LiciaCube, will follow Dart about three minutes behind,” Dr Statler said, “passing past Dimorphos at a safe distance of about 55 kilometers.”

Focusing on Dimorphos will also be The Hubble Space Telescope, the James Webb Space Telescope, and even NASA’s Lucy mission, which is on its way to study the Trojan asteroids orbiting Jupiter.

“In the first few hours after the impact, what we’re looking for is a general brightening of the entire system that indicates how much dust and other debris was kicked up,” Dr. Statler said.

Those eyes in the sky combined with ground-based telescopes and radar measurements will help Nasa determine how much, if any, Dart changes the trajectory of Dimorphos, but it won’t happen overnight.

“I think the optical observers and the radar observers have a friendly rivalry to see who’s going to get it first,” Dr Statler said. “I don’t want to get into the middle of that debate. But I think I’d be surprised if we had a solid measurement of the menstrual change in less than a few days, and I’d be very surprised if it took more than three weeks.”

Whether it’s a handful of days or much longer to get the results, and whether Dart moves Dimorphos’ orbit a lot or a little, Dr. Statler pointed out that the mission remains historic and groundbreaking, the first time humans on Earth have attempted it — with a chance of success – to change the behavior of the sky.

“We’re moving an asteroid, we’re changing the motion of a natural celestial body in space – humanity has never done that before,” Dr Statler said. “This is the stuff of science fiction books and really corny episodes of Star Trek from when I was a kid. And now it’s for real.”

Leave a Reply

Your email address will not be published.