Particle physics experiments

NASA planetary defense experiments are just getting started

Etiamophobia is the fear of an asteroid hitting the Earth, presumably ending all life as we know it. Though previously unlikely, we now have a way to protect humanity from the vagaries of an unpredictable universe.

On Monday evening, about seven million miles away, NASA’s Double Asteroid Redirection Test (DART) finally made contact with the asteroid Didymos and its football stadium-sized moon, a particularly small natural satellite. , Dimorphus. The spacecraft traveled for just over 10 months to test whether it would be possible to save Earth from future dangerous asteroids or comets by knocking them off course.

“We only have one house, so we have to take care of it,” NASA Administrator Bill Nelson said during a DART Mission Overview briefing on Monday afternoon before the mission collision. He went on to note that DART is “the world’s first mission to test Earth’s defense technology against an incoming killer asteroid.”

Thank you DARD. You served your purpose. This is the last full image of the moonlet asteroid Dimorphos before DART crashes into the surface. NASA/Johns Hopkins APL

While Earth is bombarded fairly regularly by smaller asteroids and meteors, few are noticed or pose any threat to life on the planet. While humans (so far) have been luckier than dinosaurs, it’s unclear if Earth’s good fortune will hold up. In fact, the largest asteroid impact recorded to date occurred just 115 years ago, when an asteroid the size of a 25-story building razed approximately 800 square miles of forest in an area uninhabited island of Siberia, Russia. NASA planetary defense officer Lindley Johnson told Popular Science that if a similar impact were ever to occur in a metropolitan area, it would most certainly be on the scale of a natural disaster. Johnson says DART is a “significant step” in humanity’s abilities to protect the planet from such a grim outcome.

“This is the first time that humanity has had the knowledge and the technology to start rearranging things in the solar system a bit, if you will, and making it a more hospitable place to live,” Johnson said.

[Related: NASA’s first attempt to smack an asteroid was picture perfect]

In the minutes before impact, DART hurtled towards the moon at more than 14,000 miles per hour, before striking 17 meters from the steep center and completely destroying itself around 7:14 p.m. EDT. By crashing the more than $3 million probe into the Didymos satellite, scientists expect the blow to have reduced Dimorphus’ orbital speed by at least a fraction of a millimeter per second. Because DART is about 11 billion pounds smaller than its target, the craft aimed to alter the asteroid’s trajectory, which requires less energy than trying to obliterate it completely, Johnson says. Ultimately, fending off the asteroid is a safer and safer protective maneuver. “You can never really be sure that you’re going to completely smash an asteroid or destroy it,” he says. “If you haven’t done anything to change its orbit, then you just have a bunch of coins heading your way.” It also saves valuable time before impact on the planet and better control of the object.

While data from the collision is still being collected and processed, humanity’s first attempt to move a celestial object and its first planetary defense test appears to have been a success: in addition to the loss of camera footage, the impact of the spacecraft was confirmed by a loss signal. Although it could take anywhere from weeks to months before NASA knows how far the mission has been able to push the asteroid out of orbit, the spacecraft’s ability to pin down its target has catapulted the concept of planetary defense out of the way. of the realm of the apocalypse. esque movie plots and in a real solution. But what does this triumphant first step mean for the advancement of other precautionary measures?

As the DART spacecraft has reached its valiant end, NASA scientists say the real science of the mission has only just begun. Telescopes on Earth have spent years studying and measuring the Didymos-Dimorphus system, and those same telescopes will now be trained on the system to make new measurements in its orbit relative to what it was before. Other missions that survey the vast sky, like the James Webb Space Telescope, will also soon point to the asteroid system, Elena Adams, DART mission systems engineer at Johns Hopkins Applied Physics Laboratory, told a panel. post-impact Monday evening. NASA and the public could also obtain images of the system from other active craft like LICIACube, LUCY, as well as the Hubble Space Telescope.

[Related: When Voyager 1 goes dark, what comes next?]

And the United States is not the only country investing in the defenses of our planet. In October 2024, the European Space Agency will send another probe, HERA, to examine the consequences of the DART mission, carrying out a detailed impact study that will provide scientists with the information they need to understand the experiment well enough to do it again, with even more success. . DART is only the beginning, but it marks the dawn of a universe where humans are not just passive residents, but where we can be assured of our place among the fickle cosmos.