NASA launches mission to deflect asteroid

American Space Agency sends spacecraft to collide with celestial body and deflect it from its course. The Dart mission is just a test of a new defense system, designed to prevent asteroids from reaching Earth. NASA has launched an unusual space mission: for it to be successful, the spacecraft needs to crash and be destroyed, without who has a chance of returning to Earth. In the early hours of this Wednesday (24/11), the American space agency sent a spacecraft to deliberately collide with an asteroid. It is a test of the first planetary defense system, designed to prevent a space rock from reaching Earth. It may sound like science fiction, but the Double Asteroid Redirection Test (Dart) is a true science experiment whose goal is to slightly alter the trajectory of the asteroid Dimorphos. The Dart spacecraft was launched from Vandenberg Space Force Base, in the United States, aboard a Falcon 9 rocket owned by SpaceX, the space company of billionaire businessman Elon Musk. The release was broadcast live on NASA’s television channel. “Asteroid Dimorphos, we’re coming to get you!” the agency wrote on Twitter after the launch. Later, NASA reported that Dart successfully separated from the rocket’s second stage, which in turn safely returned to Earth and landed on an aircraft carrier in the Pacific Ocean. “We have received our first signals from the Dart mission, which will continue to target its solar panels for the next few hours and prepare for its ten-month one-way trip to the asteroid,” NASA said. Not counting the extent of the solar panels, the spacecraft is the size of a large refrigerator and will travel about 11 million kilometers to Dimorphos. Impact at 24,000 km/h Dimorphos is a “moonlet” (small natural satellite that orbits a planet or other satellites) about 160 meters in diameter, which surrounds a larger asteroid called Didymos, approximately 760 meters in diameter. Together, they orbit the Sun. The impact between the spacecraft and Dimorphos is expected to occur in the second half of 2022, between September 26 and October 1, when the asteroid is 11 million kilometers away from Earth, almost the furthest point. next to the planet. Dart will hit Dimorphos at a speed of just over 24,000 kilometers per hour. Dimorphos and Didymos pose no risk to the planet. But they belong to a class of celestial bodies known as Near-Earth Objects (NEO), which transit within a radius of 30 million kilometers from Earth. “What we’re trying to learn is how to deflect a threat,” NASA scientist Thomas Zuburchen said of the $330 million project — the first of its kind. NASA’s Department of Planetary Defense Coordination is interested in asteroids over 140 meters in diameter, which can destroy cities or regions with a destructive power several times that of ordinary nuclear bombs. “Ideal natural laboratory” Scientists explain that the asteroid duo Didymos and Dimorphos is an “ideal natural laboratory” because Earth-based telescopes are able to gauge how long it takes Dimorphos to orbit its larger partner. As the period of the current orbit is known, any orbital changes will reveal the effect of the Dart spacecraft impact. Also, the pair’s orbit never crosses Earth’s orbit, so these asteroids are considered safer to study. The leader of the Dart mission investigation team, Andy Rivkin, said the asteroid Dimorphos’ current orbital period is 11 hours and 55 minutes, and the spacecraft impact will cut that time by about ten minutes. There are still uncertainties about how much energy will be transferred by the collision, as the asteroid’s internal composition and porosity are unknown. But the fact is, the more debris is generated, the more boost will be given to the Dimorphos. Other techniques There are other known methods for asteroid deflection, but the “kinetic impact” technique is the only one that can be implemented with current technology. One of the possibilities is to fly a spacecraft close to the celestial body to transmit a small gravitational force. Another is to perform a nuclear explosion near the asteroid (but not on the object itself, as staged in the Armageddon and Deep Impact movies), which would likely create many more dangerous objects. There are about 10,000 asteroids considered close to Earth to be at least 140 meters in size, but none have a significant chance of hitting the planet in the next 100 years. But an important caveat: Scientists estimate that there are still more than 15,000 of these celestial objects to be discovered. Asteroids at least 140 meters in size are estimated to strike Earth once every 20,000 years. By contrast, impacts from asteroids ten kilometers or more in diameter — like the one that collided 66 million years ago and led to the extinction of most life on Earth, including dinosaurs — occur every 100 to 200 million years. pv/ek (Reuters, AFP)

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