NASA announced on August 23 that the agency is preparing to crash a spacecraft into an asteroid in the world’s first mission to test technology to protect the Earth from threats from asteroids or comets. They also invite the world to watch this one-of-a-kind event.
Simulation of NASA’s DART spacecraft before crashing into the asteroid Dimorphos in binary. Photo: NASA
Viewers can watch the live broadcast of the DART spacecraft collision on NASA TV and the NASA website. The public can also view the event on NASA’s social media accounts, including Facebook, Twitter, and YouTube. Ahead of the September 27 collision, NASA will hold a briefing from the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, which builds and manages the DART spacecraft.
DART was the world’s first planetary defense test mission, conducting a deliberate collision with the asteroid Dimorphos to alter its motion through the universe. Although the asteroid poses no danger to Earth, the DART mission will demonstrate that spacecraft can autonomously find their way to collide with a relatively small target asteroid, and this is a viable technique to redirect an asteroid. celestial bodies that are likely to collide with the Earth. DART will come close to its target on September 26. “DART will provide important data that will help us be better prepared if we detect an asteroid that threatens to hit Earth,” NASA said.
According to NASA, the target of DART is the binary near-Earth asteroid system Didymos. This system includes the asteroid Didymos with a diameter of 780 m, and the smaller object Dimorphos with a diameter of 162 m. DART will crash into Dimorphos.
Using some of the world’s most powerful telescopes, in August 2022, the DART team completed a six-night observations to confirm initial calculations of Dimorphos’ orbit around the larger parent asteroid. was Didymos, confirming the object was at the impact site.
This is the world’s first attempt to alter the velocity and trajectory of an asteroid moving through space, testing a method of navigation that could be useful if Earth’s defenses are needed in the future.
“The measurements the team has taken since early 2021 are critical to ensuring that DART arrives at the right place and time for the Dimorphos collision,” said Andy Rivkin, co-leader of the DART research team at APL. shall. “Confirming the measurement results through new observations shows that we did not need to change the flight path and were close to the target.”
If DART succeeds in altering Dimorphos’ flight path, the object will move closer to Didymos, shortening its orbit. But scientists need to confirm nothing else is affecting the asteroid’s orbit, including radiation from the asteroid’s surface that can push and cause its orbit to change.
From late September to early October, around the time of the collision with DART, Didymos and Dimorphos will come closest to Earth in recent years at a distance of 10.8 million km. As of March 2021, the Didymos binary system is out of range of most ground-based telescopes due to its distance from Earth.
But in early July, the DART team used powerful telescopes in Arizona and Chile – including the Lowell Discovery telescope at the Lowell Observatory, the Magellan telescope at the Las Campanas Observatory and the Southern Astrophysical telescope Research (SOAR) – to monitor the asteroid system and look for changes in the system’s luminosity. These changes occurred when one of the asteroids passed in front of the other because Dimorphos’ orbit blocked part of their light.
Studying the change in brightness allows scientists to determine exactly how long it takes Dimorphos to orbit the larger asteroid, thereby predicting Dimorphos’ position at several points in time, including the spacecraft moment DART turret crashes. The results are consistent with previous calculations. Through the latest round of observations, the team was able to make adjustments to determine whether and to what extent DART successfully altered the trajectory of Dimorphos after the collision.
In October this year, the team will once again use ground-based telescopes around the world to calculate the new orbit of Dimorphos. They expect the smaller asteroid’s time to orbit Didymos to shift by a few minutes.
