Illustration of the DART spacecraft approaching two asteroids; it will crash into the smaller one to try to change the way this space rock orbits its larger companion.
NASA / Johns Hopkins APL / Steve Gribben
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NASA / Johns Hopkins APL / Steve Gribben
Illustration of the DART spacecraft approaching two asteroids; it will crash into the smaller one to try to change the way this space rock orbits its larger companion.
NASA / Johns Hopkins APL / Steve Gribben
NASA is about to embark on an unprecedented mission of knocking an asteroid that has gone slightly off track.
In the first real test of a technique that could one day be used to protect Earth from an endangered space rock, a spaceship is expected to explode from Vandenberg Space Force Base in California on Tuesday, November 23 at 10:20 p.m. PST.
The golf cart-sized spacecraft will travel to an asteroid more than 6 million miles away – and pose no danger to Earth – and crash into it. Scientists will then monitor to see how the asteroid’s orbit changes.
NASA has identified and tracked nearly all nearby asteroids whose size could cause world-changing damage if they hit Earth. In the near future, no big company is going our way. But there are many smaller asteroids, the size of which could destroy an entire city, that have yet to be found and tracked.
It’s a smaller space rock that the DART mission – which stands for Double Asteroid Redirection Test – will do.
“A lot of times when I tell people that NASA is actually working on this mission, at first they don’t believe it, maybe because it used to be in the movies,” he said. Nancy Chabot, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory.
Movies like Apocalypse or Meteor There’s usually an impending, unexpected killer asteroid, and saving humanity always requires blowing it to pieces with a nuclear bomb.
In fact, messy and unpredictable nuclear weapons are not the preferred choice of planetary defense experts who want to identify dangerous space rocks before any collision. possible and use more controlled methods to change its path.
“The right time to deflect an asteroid as far away from Earth as possible,” Lindley JohnsonNASA Planetary Protection Officer. “The strategy is to look for these objects not just years but decades before they pose any kind of impact risk to Earth.”
In the cleanroom at Johns Hopkins APL, NASA’s DART spacecraft is moved into a dedicated transport bin attached to its launch pad at Vandenberg Space Force Base in California.
NASA / Johns Hopkins APL / Ed Whitman
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NASA / Johns Hopkins APL / Ed Whitman
In the cleanroom at Johns Hopkins APL, NASA’s DART spacecraft is moved into a dedicated transport bin attached to its launch pad at Vandenberg Space Force Base in California.
NASA / Johns Hopkins APL / Ed Whitman
With enough advance warning, NASA could send a spacecraft that simply pushes an asteroid slightly, changing its course so that it no longer causes problems. That’s the approach NASA is experimenting with with DART.
Chabot, DART’s coordinator, said: “DART is demonstrating asteroid deflection. It’s not asteroid disruption at all, that’s how it happens so many times over the course of time. film”.
The asteroid targeted by DART is not a threat to the planet, and Chabot says it’s unlikely this mission could turn it into one. “There is absolutely no way that DART testing is a threat to the Earth,” she said.
After launching the DART spacecraft, it will take about 10 months to reach an asteroid called Didymos, which is about 2,500 feet across. This asteroid is orbited by a smaller asteroid called Dimorphos, which is about 525 feet across.
It is the small asteroid, Dimorphos, that will be hit by the spacecraft. “So it’s like a small golf cart running into a Great Pyramid – just this ‘golf cart’ will go 15,000 miles per hour,” says Chabot.
During the mission’s final few hours, return-to-Earth managers will only be able to observe as the spacecraft flies on its own and flies to its target.
“It’s four hours of watching the paint dry, but it’s really terrifying at the same time because the spacecraft is fully autonomous,” Elena Adams, mission systems engineer at the Johns Hopkins University Applied Physics Laboratory.
Initially, the spacecraft will orient itself by aiming for the larger asteroid, Adams explained. Then, in the last hour interval, it will detect the smaller one and switch to that target.
Images sent back by the dead spacecraft in the final seconds before the crash will give scientists the first glimpse of Dimorphos. No one knows what shape this asteroid is, whether its surface is smooth or rough. In fact, this pair of asteroids is so small and so distant that telescopes can see them with just a single point of light.
However, changes in brightness will tell scientists when the orbiting Dimorphos pass in front of its companion. Currently, Dimorphos works approximately every 11 hours and 55 minutes. The impact would shorten that time, but scientists don’t know how many minutes.
Adams said that the telescope will be watching closely in the weeks and months after the collision to “see how it reacts to being pushed.”
A small satellite launched from the spacecraft 10 days before the collision would send back images of the collision itself and the resulting explosion of debris.
Furthermore, the European Space Agency is expected to launch a mission in 2024 will travel to these two asteroids and be able to observe the crater on Dimorphos and determine the asteroid’s mass.
All of these results will help NASA and other space agencies understand what can be done with this kind of “dynamic deflection” method in the future, if an asteroid is headed toward Earth. soil.
“Assuming we don’t have any major surprises, we think this technique, which will be available by then, will be part of the toolbox where we are starting to build capabilities to make things better,” Johnson said. deflect an asteroid.
After this test, he said, NASA will want to try other asteroid deflection techniques, like the so-called “gravity tractor” approach, which involves placing a spacecraft near an asteroid to create a small gravitational force.
Diagram of this DART mission showing the impact on the moon by asteroid (65803) Didymos.
NASA / Johns Hopkins Applied Physics Laboratory
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NASA / Johns Hopkins Applied Physics Laboratory
Diagram of this DART mission showing the impact on the moon by asteroid (65803) Didymos.
NASA / Johns Hopkins Applied Physics Laboratory
Of course, the dreaded asteroids can only be deflected once NASA knows they exist. Astronomers believe they have located and tracked at least 90% of the largest nearby asteroids, meaning those more than 3,280 feet across.
“None of them are a threat for the foreseeable future,” says Chabot. “That is a good news.”
But a single hit from a smaller asteroid, about 450 feet in diameter, could rob a city and devastate an area. And scientists currently know only about 40% of such objects that are thought to be out there.
That’s why NASA’s planetary protection office is supporting the development of a new spaceflight telescope to search more in that size range.
“While there is currently no known asteroid that is in the process of colliding with Earth, we do know that there are a large number of near-Earth asteroids out there,” Johnson said.
