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Can you change the trajectory of an asteroid to prevent it from falling to Earth? 2:34
(CNN) - In two years, NASA will demonstrate its asteroid deflection technology on the recently named Dimorphos, a moon that orbits the near-Earth asteroid Didymos. This will be the agency's first large-scale demonstration of this type of technology in the name of planetary defense.
Dimorphos got its name last week, just in time to reflect on the importance of understanding the threat from near-Earth asteroids. The objects close to our planet are asteroids and comets whose orbits place them 50 million kilometers from Earth.
This Tuesday is International Asteroid Day, commemorating the largest recorded asteroid impact while focusing on the real danger from asteroids that could collide with Earth.
In 1908, a powerful asteroid hit the Podkamennaya Tunguska River in a remote Russian Siberian forest. The event razed trees and destroyed forests over 1,200 square km, equivalent to the size of three-quarters of the US state of Rhode Island. The impact threw people to the ground in a city 65 km away.
In 2013, an asteroid entered Earth's atmosphere above Chelyabinsk, Russia. It exploded in midair, releasing 20 to 30 times more energy than that of the first atomic bombs, generating a higher brightness than that of the Sun, exuding heat, damaging more than 7,000 buildings and injuring more than 1,000 people. The blast wave broke the windows 93 kms away. The asteroid was not detected because it came from the same direction and path as the Sun.
This explains why astronomers and the Asteroid Day group want people to be aware. Detecting the threat of near-Earth objects that could cause serious damage is a primary focus of NASA and other space organizations around the world.
And in 2022, NASA will test its asteroid deflection technology to see how it impacts the motion of a near-Earth asteroid in space.
READ : The asteroid that wiped out the dinosaurs struck at the "deadliest possible" angle
Didymos and Dimorphos
Two decades ago, a binary system involving a near-Earth asteroid was discovered to have an orbiting moon, called Didymos. In Greek, Didymos means "twin," which was used to describe how the largest asteroid, which is nearly 0.8 km in diameter, is orbited by a smaller moon that is 160 meters in diameter. At that time, the moon was known as Didymos b.
But when the binary system became the target of NASA's 2022 Double Asteroid Redirection Test mission, or DART, it was time for the moon to get an official name.
Last week, the International Astronomical Union officially named the moon Dimorphos. Kleomenis Tsiganis, a planetary scientist at Aristotle University of Thessaloniki and a member of the DART team, suggested the name.
"Dimorphos, which means 'two shapes', reflects the status of this object as the first celestial body to have the 'shape' of its orbit significantly changed by humanity, in this case, by the impact of DART," said Tsiganis . As such, it will be the first object known to humans in two very different ways, one seen by DART before impact and another seen by Hera from the European Space Agency a few years later. "
By the end of 2022, Didymos and Dimorphos will be relatively close to Earth and 10 million km from our planet, the perfect time for the DART mission to occur.
The DART will deliberately crash into Dimorphos to change the motion of the asteroid in space, according to NASA. This collision will be recorded by LICIACube, a CubeSat or cube satellite provided by the Italian Space Agency. The CubeSat will travel on the DART and then deploy from it before impact so you can record what happens.
"Astronomers will be able to compare observations of ground-based telescopes before and after the kinetic impact of DART to determine how much Dimorphos's orbital period changed," said Tom Statler, a DART program scientist at NASA headquarters, in a statement. "That is the key measure that will tell us how the asteroid responded to our diversion effort."
LOOK : Can you change the trajectory of an asteroid to prevent it from falling to Earth?
A few years after the impact, the European Space Agency's Hera mission will carry out a follow-up investigation of Didymos and Dimorphos.
While the DART mission was developed for NASA's Planetary Defense Coordination Office, and was administered by the Johns Hopkins University Applied Physics Laboratory, the mission team will work with the Hera mission team under an international collaboration known as Asteroid Deflection and Impact Assessment, or AIDA.
"DART is a first step in testing methods for the diversion of dangerous asteroids," said Andrea Riley, executive of the DART Program at NASA headquarters, in a statement. "Potentially dangerous asteroids are a global concern, and we are excited to work with our Italian and European colleagues to collect the most accurate data possible from this demonstration of kinetic impact deflection."
A first time mission
Dimorphos was chosen for this mission because its size is similar to asteroids that could pose a threat to Earth.
The DART will collide with Dimorphos moving at 237,600 km per hour. A camera on the DART, called DRACO, and autonomous navigation software will help the spacecraft detect and collide with Dimorphos.
This rapid impact will only change Dimorphos speed while orbiting Didymos by 1%, which doesn't sound like much, but it will change the moon's orbital period in several minutes. That change can be observed and measured from ground-based telescopes on Earth. It will also be the first time that humans have altered the dynamics of a body in the solar system in a measurable way, according to the European Space Agency.
The DART launch window opens in July 2021 with the expected impact in 2022.
Three years after the impact, Hera will arrive to study Dimorphos in detail, measure the moon's physical properties, study the impact of DART, and study its orbit.
This may seem like a long time to wait between impact and follow-up, but it builds on lessons learned in the past.
In July 2005, NASA's Deep Impact spacecraft launched a 370-kilogram copper impact at a comet, Tempel 1. But the spacecraft was unable to see the resulting crater because the impact released tons of dust and ice. However, NASA's Stardust mission, in 2011, was able to characterize the impact: a 150-meter wound.
Together, the valuable data collected by DART and Hera will contribute to planetary defense strategies, especially by understanding what kind of force is needed to change the orbit of a near-Earth asteroid that can collide with our planet.
Asteroid