They artificially change the motion of an asteroid

For the first time, humanity has managed to change the movement of a celestial body in space using a space probe used as a projectile.

Analysis of data obtained over the past two weeks by NASA’s DART mission research team demonstrates that the deliberate impact of the DART spacecraft against its target asteroid, Dimorphos, successfully altered the orbit of the asteroid. The experiment is the first large-scale demonstration of this asteroid deflection technology.

The usefulness of this technology is to protect the Earth from the impact of asteroids, diverting the trajectories of all those that have a collision course with our planet or that are going to pass dangerously close.

Before the DART impact, Dimorphos took 11 hours and 55 minutes to orbit the larger asteroid Didymos. Since DART’s collision with Dimorphos on September 26, astronomers have been using ground-based telescopes to measure how much that time spent making one complete revolution around Didymos has changed. Now, the research team has confirmed that the spacecraft impact altered Dimorphos’s orbit around Didymos by 32 minutes, shortening the orbit from 11 hours and 55 minutes to 11 hours and 23 minutes. This measurement has a margin of error of approximately 2 minutes.

Before the impact, NASA had defined a minimal successful change in Dimorphos’s orbit period as a change of 73 seconds or more. This early data shows that DART exceeded this minimum benchmark by more than 25 times.

“This result is an important step in understanding the full effect of DART’s impact on its target asteroid,” explained Lori Glaze, director of NASA’s Planetary Science Division. “As new data comes in daily, astronomers will be able to better assess whether a mission like DART could be used in the future to help protect Earth from a collision with an asteroid, if we ever find one headed our way, and How could we do it?”

This image, taken by NASA’s Hubble Space Telescope on October 8, 2022, shows debris dislodged from the surface of Dimorphos 285 hours after the DART impact on September 26. The shape of the rest wake has changed over time. This material and how it moves in space is still being studied. (Photo: NASA / ESA / STScI / Hubble)

The research team is still acquiring data from ground-based observatories around the world, as well as from radar facilities such as NASA’s Jet Propulsion Laboratory (JPL) in Goldstone, California, and Green Bank Observatory in the US National Science Foundation in West Virginia. Scientists are updating the period measurement with frequent observations to improve its accuracy.

An analysis of the “ejection” of the many tons of rock from the asteroid that was displaced and hurled into space by the impact is also underway. The recoil produced by this debris explosion substantially enhanced DART’s thrust against Dimorphos, a bit like the way a jet of air coming out of a balloon sends the balloon in the opposite direction.

To fully understand the effect of ejection recoil, more information is needed about the physical properties of the asteroid, such as its surface features and how strong or weak it is. These issues are still under investigation.

For the analyses, astronomers will continue to study the images of Dimorphos obtained by DART itself moments before the impact, and the images obtained by the Italian CubeSat LICIACube, provided by the Italian Space Agency and which traveled with DART until it separated from it upon arrival. in the vicinity of the binary asteroid system. Analysis of all these photos is expected to help obtain a reasonably accurate estimate of the asteroid’s mass and shape.

In about four years, the ESA (European Space Agency) Hera project will also carry out detailed studies of both Dimorphos and Didymos, paying particular attention to the crater left by the DART collision and making much more precise measurements of Dimorphos’ mass. .

Neither Dimorphos nor Didymos pose any danger to Earth, before or after DART’s controlled collision with Dimorphos. (Source: NASA)