SpaceX has launched a mission that will intentionaly slam into an asteroid. The mission, called the Double Asteroid Redirection Test (DART), will test a proposed method for redirecting asteroids that routinely cross Earth’s orbit and may eventually slam into Earth with catastrophic consequences.
To pose a threat, asteroids have to be big enough to survive a trip through Earth’s atmosphere. Most burn up as “shooting stars.” However, as the below Discovery Channel documentary shows, there are several potential “planet-killers” floating around out there.
A prevailing theory is that the extinction of the dinosaurs was caused by a gigantic asteroid that slammed into Earth 65 million years ago. More recently, the Tunguska event of June 30, 1908, generated the equivalent of a 12-megaton explosion, flattening 80 million trees and killing animals, including hundreds of the reindeer that were critical to the way of life of many Siberians, over a 2,150 km2 zone. The explosion was so intense that at least one person 40 miles away from the blast reported feeling like he was on fire and some locals believed that it was the action of an angry god.
One theory has it that, if the Tunguska asteroid had entered the atmosphere just a couple of hours earlier, it could have flattened the city now called St. Petersberg and killed tens of thousands of people.
NASA has also detected several enormous asteroids that have whizzed past Earth at distances that are less than the distance between the Moon and Earth. If they had been just a little closer to Earth, the results could have been catastrophic.
Individuals who have expressed concern about similar asteroids include Carl Sagan, Stephen Hawking and Elon Musk. Noted theoretical physicist Michio Kaku has also endorsed Elon Musk’s plans to settle Mars.
Musk especially is putting considerable effort into making humanity a multi-planet species as a way to “hedge our bets” and make sure we aren’t complete sitting ducks in case of an eventual asteroid strike on Earth. SpaceX president Gwynn Shotwell has even admitted that one goal for the Starlink satellite Internet service is to help fund crewed missions to Mars once it comes out of beta and starts generating a revenue stream by tapping the untapped markets for high-speed Internet in low-income or sparsely populated areas.
DART will target asteroids that do not pose a threat, but can be easily seen by Earth-based telescopes. This will make it easier for NASA’s scientists to analyze the results. NASA said in a statement:
“DART will show that a spacecraft can autonomously navigate to a target asteroid and intentionally collide with it – a method of deflection called kinetic impact. The test will provide important data to help better prepare for an asteroid that might pose an impact hazard to Earth, should one ever be discovered.”
Europe’s ESA is planning a follow-up mission called Hera, which will land a probe in the crater created by DART’s impact on one of the target asteroids. The ESA is targeting a launch date in about four years.
The twin asteroids are named Didymos and Dimorphos. DART aims to crash the spacecraft into the smaller Dimorphus, which orbits Didymos, at four miles per second when it arrives between September 26 and October 1, 2022.