NASA prepares 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)

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

But accepting the inevitability of an asteroid hitting a planet doesn’t sit well with NASA, and on Monday, the space agency is doing something about it: testing a technique for deflecting dangerous asteroids away from Earth by hitting them with a spacecraft. fast movement.

“Ground systems are ready 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 news conference Thursday about the test. “We have a lot of propellant and we have a lot of power.”

APL manages the operations of the Dart (Double Asteroid Redirection Test) spacecraft for NASA, and Mr. Reynolds is the program manager for the mission. It 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 slightly change its orbit — asteroid does not pose a threat to Earth.

It is the first mission of its kind and ambitious.

“Dimorphos is just over 100 meters in diameter; it’s not very big. We’re at 14,000 miles per hour, we’re getting close to 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 an expanded version of this “kinetic impactor” technique could deflect a larger asteroid or comet threatening Earth, the NASA Dart Program Scientist Tom Statler.

“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 real asteroid responds 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 in diameter 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 of Didymos. Scientists hope that the impact of the darts could reduce the orbit time by between 73 seconds and 10 minutes, assuming the mission is successful.

A successful mission would confirm scientific models of how asteroids like Dimorphos behave, Dr. Statler added, and give NASA confidence in its design of any future mission to deflect a real threatening asteroid.

“On the other hand, if the asteroid responds to the dart impact in a totally unexpected way,” he said, “that might make us reconsider whether, to what extent, the kinetic impact is actually usable.”

It won’t be long until NASA and APL get an answer to that question, as Dart is rapidly closing in on the Didymos and Dimorphos system.

“About 24 hours before impact, everyone will be ready,” APL Dart mission systems engineer Elena Adams told reporters at APL on Thursday. Although Dart will transition to fully autonomous flight four hours before impact, APL operators will be ready to intervene if anything goes wrong, even if the small asteroid is missed.

“We have 12 contingencies, and number 21 is ‘Missing Impact,’” said Dr. Adams. “We’ll start conserving propellant and start looking for items to return to. So that’s the plan.”

Dart took its first image of the two asteroids in July, and what were tiny pinpoints of light will grow rapidly 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 traveling so fast, Dr Adams said, that the asteroid will remain relatively small until the last moments before impact, giving scientists their first real look at the asteroid’s shape and texture.

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

NASA will broadcast Dart’s impact live in two different broadcasts. A silent broadcast of images from Dart’s Draco camera, approximately one image per second, will be available on NASA’s media channel starting at 5:30 p.m. EDT, while a broadcast with commentary and Draco’s images will be will be able to watch on Nasa TV starting at 6 p.m.

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

“The engineering team will be celebrating and the astronomers at that point will say, ‘OK, time to get to work,'” he said.

That’s because a wide range of telescopes on the ground and in space will watch Dimorphos for signs of Dart’s impact, and then keep checking the asteroid for signs that its orbit has changed.

The first and most important will be the Light Italian CubeSat for Imaging of Asteroids, or LiciaCube, a small satellite produced and operated by the Italian Space Agency that traveled on Dart until its separation on September 11. It will be able to record the impact and any resulting material that is expelled from Dimorphos.

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

Also focusing on Dimorphos will be the Hubble Space Telescope, the James Webb Space Telescope and even NASA’s Lucy mission, which is underway to study Trojan asteroids in Jupiter’s orbit.

“In the first few hours after impact, what we’re looking for is an overall system-wide glow that indicates how much dust and other debris was kicked up,” said Dr. Statler.

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

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

Whether it takes a few days or much longer to get the results, and whether Dart moves Dimorphos’s orbit a lot or a little, Dr. Statler noted that the mission remains historic and groundbreaking, the first time people on Earth he has tried, with a chance of success, to change the behavior of the heavens.

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

Leave a Reply

Your email address will not be published.