If an asteroid were indeed on a collision course with Earth, would we end up like the dinosaurs or would we be able to deflect it? Second movie like Armageddon e Deep Impact our heroes will save the planet, which would suffer only minor damage. Scientists, however, prefer something more concrete than a Hollywood blockbuster and want to do a field test. That is to try to deflect an asteroid from its orbit, even slightly but sufficiently to avoid a devastating impact against our planet. This is the meaning of the Dart (Double Asteroid Redirection Test) mission which starts Wednesday from the Vandenberg base, in California, with a Falcon 9 rocket from Elon Musk’s SpaceX company, in which Italy participates with an important technical-scientific contribution. After a journey of more than 10 months, towards the end of next September Dart will reach the asteroid Didymos, at a distance of 11 million kilometers from Earth. Although the asteroid has a diameter of only 780 meters, about two and a half times the Eiffel Tower, it has a small satellite called Dimorphos, which orbits around it in 11 hours and 55 minutes.
The aim is to impact the Dart probe, with its mass of 550 kilos, at a speed of 24,000 kilometers per hour against the surface of Dimorphos. This will cause a small explosion, a crater and raise several tons of dust and debris. The impact, however, will give Dimorphos a little “nudge” by changing its orbit. How much? Not by much: the technicians expect a change of about 10 minutes of the period of revolution of Dimorphos around Didymos. A variation of 73 seconds would be the minimum limit to consider the mission a success: a result sufficient to demonstrate that the orbit of a “dangerous” asteroid could change with a high-speed impact with a high-mass object launched from Earth. “For the first time, humanity will change the motion of a natural celestial body in space,” commented NASA scientist Tom Statler.
Ten days before the collision, Dart will release the LiciaCube mini-probe of the Italian Space Agency (ASI), built with the participation of Argotec, Ifac-Cnr, Politecnico di Milano, University of Bologna and Parthenope of Naples and five observers from the National Institute of astrophysics (Inaf). The mini-probe will have to document the impact, fly over Dimorphos three minutes later and send the data to Earth that will also be used to study the nature of the small orbiting body of only 180 meters, but with an age that should go back to the early stages of the Solar System 4 , 6 billion years ago. “The role of LiciaCube is important for the success of the mission and many challenges have been faced, also because the microsatellite will have to independently manage the operational phases”, said Giorgio Saccoccia, president of ASI. LiciaCube will be the Italian satellite to operate farthest from Earth and will be managed by an all-Italian team coordinated by Elisabetta Dotto of INAF. In 2026 the Didymos system will be reached by the European Hera mission which will accurately measure the results obtained
November 24, 2021 – Updated November 24, 2021, 09:17 am