Why NASA plans to slam a spacecraft into an asteroidThe DART mission will intentionally crash into a space rock to test the technologies we may need to save the world.
BY NADIA DRAKE PUBLISHED APRIL 28, 2020
(...) The bigger asteroids, including 1998 OR2 and 1990 MU, could devastate life across the planet if they hit. “It is estimated that asteroids of one kilometer or more would result in continent-wide devastation, and the dust injected into the atmosphere would cause drastic cooling and the possibility of global crop failures for at least a few years,” says Jay Melosh, a geophysicist at Purdue University.
We’ve found roughly 900 of these larger objects, or 95 percent of the estimated total population. None are even remotely likely to hit the planet in the next several centuries. But of the smaller group, which could still destroy cities, we’ve only detected roughly 30 percent of the estimated 25,000 objects, according to a report from the National Science and Technology Council. (...)
Shortly before DART smashes into Didymoon at roughly 14,700 miles an hour, the spacecraft will release a shoebox-size camera made by the Italian Space Agency. The camera will watch as the spacecraft smashes into Didymoon, taking pictures of the spray of debris and perhaps even of the resulting crater. Johnson says he expects the collision could decrease the moon’s 12-hour orbit by as much as seven minutes, although the team will consider the mission a success if that change is at least 70 seconds. (...)
https://www.nationalgeographic.com/science/2020/04/giant-asteroid-nasa-dart-deflection/