NASA just successfully completed its first practice run of a technique that might just save the world from an asteroid impact.
The mission began on Nov. 24, 2021, when the Double Asteroid Redirection Test (DART) probe lifted off from Vandenburg Air Force Base onboard a SpaceX Falcon 9 rocket. On Sept. 26, 2022, DART reached the end of its journey when it smashed into an asteroid called Dimorphos, which orbits a larger asteroid named Didymos, at a speed of 14,000 miles per hour. The very last image returned from DART before impact was of Dimorphos’ rubble-strewn landscape.
The mission’s goal was to change Dimorphos’ orbit (between 73 seconds and 10 minutes). Scientists will not know for weeks how great an effect the impact had. While this was not a danger to us, if a similar impact were to be achieved against an asteroid that were headed for a collision with Earth, the smallest change in direction and speed might be enough to spare our home planet from devastation. All would depend on how far away the potential killer asteroid was. The farther away it was, the easier it would be to deflect in time.
When we can deflect an asteroid that is still years away from hitting the Earth, we avoid riskier methods. Scenarios in which heroic astronauts travel to the approaching space rock to blow it up may make for great cinema. However, setting off an explosive on or inside an asteroid or comet would make a lot of little rocks out of one big one and perhaps make the problem worse.
Thus, NASA wants to detect killer asteroids in time to ward them off. In 2021, NASA authorized funding for a space telescope called the Near-Earth Object or NEO Surveyor that would be dedicated to detecting and characterizing Earth-approaching asteroids that may be a threat. Currently, NEO Surveyor is scheduled to launch in 2026 for a mission lasting at least five years.
NEO Surveyor will be 20 inches in diameter and will search the heavens for Earth-approaching objects in the infrared range. The project’s goal is to locate at least two-thirds of the near-Earth objects that are 460 feet in diameter or wider.
The telescope will be able to gather data about the objects’ composition, shapes, rotational states and orbits. If any of these objects constitute even a remote threat to Earth, scientists can develop a strategy to deflect them, perhaps by colliding a spacecraft into them or perhaps by some other method.
The NEO Surveyor will go a long way toward meeting Congress’ mandate to discover at least 90 percent of near-Earth objects that might threaten the home planet.
The DART test and the NEO Surveyor will be the most important missions that NASA has ever undertaken. The Apollo moon landings brought great knowledge and political prestige. The International Space Station continues to operate as a symbol of international cooperation in pursuit of science. The various planetary probes NASA has launched have unlocked some of the secrets of the solar system. The Artemis Program will restore the lost promise of Apollo and open the moon to scientific exploration and economic development.
However, by locating near-Earth objects and developing strategies to divert them from a collision with the home planet, if necessary, NASA may well save the world. Every school child has studied how an asteroid ended the reign of the dinosaurs 66 million years ago. A similar object, if left unimpeded, would end the human species. An old joke states that the dinosaurs went extinct because they did not have a space program.
NEO Surveyor will have a second beneficial result. By locating near-Earth objects and gathering data on their composition, it will be able to uncover what mineral wealth awaits in the sky for space miners to prospect and extract. Perhaps decades hence, robots can be dispatched to mine the asteroids and bring back valuable minerals to space-based manufacturing facilities to make useful products. The economic sphere of human civilization will have expanded beyond Earth.
Two of the strongest human emotions are fear and greed. The former will motivate us to develop a planetary defense against asteroids and comets. The latter will spur us on to tap the riches these space rocks contain for the betterment of humankind.
Mark R. Whittington is the author of space exploration studies “Why is It So Hard to Go Back to the Moon?” as well as “The Moon, Mars and Beyond,” and “Why is America Going Back to the Moon?” He blogs at Curmudgeons Corner.