We’ve long said that humans generally worry about the wrong asteroids. Tabloids love to publish headlines about “potentially hazardous asteroids,” a category created by NASA that can be a bit misleading. The truly worrisome rocks are the smaller ones that we aren’t tracking.
The US National Science and Technology Council knows about this problem—and thankfully, it plans to do something about it, according to a report the council released in late June.
A 2005 US Congress mandate stated that NASA would try to keep track of 90 per cent of the near-Earth objects larger than 460 feet (140 metres). America is sonly a third of the way there, reports Quartz, and even then, its existing catalogue might be flawed, according to a recent paper. But before something can be tracked, it must be documented, and even that effort is behind scheduled, according to the new report:
Since 2005, the number of NEOs catalogued in this range has almost tripled, while the total number of catalogued NEOs has increased by almost five times. Nevertheless, according to a 2017 report from NASA’s NEO Science Definition Team, current observational capabilities are suited to only finding less than half of all 140 metre objects by 2033, and planned improvements will still fall short of the timeline that Congress directed.
But smaller asteroids can also be a problem, like the 60-foot-wide Chelyabinsk meteor that went undetected until it exploded over Russia and injured a thousand people. A slightly larger rock over a more populated area could be catastrophic.
America's National Near-Earth Object Preparedness Strategy and Action Plan lays forth a long list of activities that would better prepare the US for a strike. Its goals include improving capabilities for detecting and tracking these objects, including the ones between 50 and 140 metres in size that could be catastrophic on a local level. This means improving the ability of telescopes and computers to understand asteroids’ size and composition.
It also seeks better simulations to assess risk, which would be used by groups such as the US Federal Emergency Management Agency (FEMA), the US Department of Defense, the US Defense Threat Reduction Agency, and others. It calls for the creation of a group charged with disseminating the results of these new models. It would also develop quick-response missions for deflecting or disrupting threatening asteroids, and figure out how to cooperate with foreign governments on this issue. Finally, it would strengthen and set up practice protocols for what to do in the event of an impending impact, in order to improve on the existing plan.
The report recognises that near-Earth objects have the potential to be really, really bad, and aims to make the US more prepared for such a strike. “Implementing the NEO Action Plan will increase the United States’ ability and readiness, together with domestic and international partners, to mitigate the impact hazard posed by NEOs,” the report says.
There are already some relevant missions in the works, like NASA’s Asteroid Redirect Mission, the OSIRIS-REx spacecraft, which is on its way to study potentially hazardous asteroid Bennu, and the Double Asteroid Redirection Test (DART) mission, “the first demonstration of the kinetic impact technique to change the motion of an asteroid in space.”