NASA on asteroid defense: If it’s coming in three weeks, pray
On February 15, a small asteroid exploded over Chelyabinsk, Russia, generating shock waves that shattered windows and injured some 1,500 people. On that same day, asteroid 2012 DA14 made a close pass by Earth, at a scant 17,200 miles (27,700 km) from our world’s surface, closer than some communication satellites. In response to these events, the U.S. House Science, Space, and Technology Committee met in a hearing on March 19, 2013. The hearing was titled Threats from Space: A Review of U.S. Government Efforts to Track and Mitigate Asteroids and Meteors. Scientists and lawmakers discussed the risk of, and defense strategy for, an unforeseen asteroid or meteor on collision course with Earth. While trying to emphasize the need for adequate funding for detecting and characterizing near-Earth objects, and diverting them if necessary, NASA Administrator Charles Bolden said:
From the information we have, we don’t know of an asteroid that will threaten the population of the United States. But if it’s coming in three weeks…pray.
In other words, unless we know in advance that an asteroid is coming – and therefore have time to divert it – there is little we could do about an asteroid on a collision course with Earth. Bolden added:
The reason I can’t do anything in the next three weeks is because for decades we have put it off.
NASA is currently tracking about 95 percent of Near Earth Objects (NEOs) that are .62 miles (nearly 1,000 meters) or larger in diameter. White House Science Advisor John Holdren told legislators that:
… an asteroid of that size, a kilometer or bigger, could plausibly end civilization.
So far, none of the objects NASA is tracking appear to be an immediate threat. However, as Chairman Smith pointed out:
The meteor that struck Russia was estimated to be 17 meters and wasn’t tracked at all. The smaller they are, the harder they are to spot, and yet they can be life-threatening. Some space challenges require innovation, commitment and diligence. This is one of them.
A small asteroid – like the one that exploded over Russia on February 15 – would not be world destroying. But clearly objects smaller than .62 miles (1,000 meters) have the potential to cause damage.
Representative Eddie Bernice Johnson (D-TX) said the events on February 15:
… serve as evidence that we live in an active solar system with potentially hazardous objects passing through our neighborhood with surprising frequency.
John Holdren said the best way to detect objects that might be on a collision course with Earth would be to put an infrared-sensing telescope in a Venus-like orbit. Holdren estimated the cost of such a telescope to be between $500 million and $750 million. Another costly and time-intensive undertaking would be mounting a mission to divert a threatening object after detection. NASA’s hunt for threatening asteroids will be affected by federal sequestration cuts, and at present funding levels NASA estimates it will take nearly 20 years to identify all potentially threatening Near Earth Objects.
One solution that all lawmakers seemed amenable to was crowdsourcing, that is, working with other countries and amateur astronomers to crowdsource the hunt for threatening asteroids. Holdren said:
The odds of a Near-Earth Object strike causing massive casualties and destruction of infrastructure are very small, but the potential consequences of such an event are so large it makes sense to take the risk seriously.
Bottom line: On March 19, 2013, the House Science, Space, and Technology Committee met in a hearing titled Threats from Space: A Review of U.S. Government Efforts to Track and Mitigate Asteroids and Meteors. Legislators, NASA administrators and others discussed the need for adequate funding for detecting and characterizing near-Earth objects, and diverting them if necessary.