On December 30, the White House quietly released its Near-Earth Object Preparedness Strategy, a 25-page document outlining the United States' plans in the event that a giant asteroid is found to be on a collision course with Earth. Among the priorities outlined by the strategy are improving Near-Earth Object (NEO) detection, developing methods for deflecting asteroids, and developing interagency emergency procedures in the event of an NEO impact.
"If we were to be faced with a serious asteroid impact hazard, it's going to take more than just NASA to try to do something about it in space," Lindley Johnson, NASA's Planetary Defense Officer, told Motherboard in a phone call. "If there's not enough time to do something about the asteroid in space, it's going to take efforts by a lot of agencies to prepare to take the hit. This is really the first time we've tried to pull together an all-government preparedness strategy for dealing with this very serious natural disaster."
Near-Earth Objects are asteroids or comets whose orbits around the Sun un intersect with or come near Earth's orbit. Several thousand NEOs have been discovered, ranging in size from a few dozen meters to several kilometers in diameter. Every day the Earth gets hit with dozens of these space rocks, but most are so small that they burn up in the atmosphere before ever reaching the surface. Inevitably, however, one of the larger asteroids will hit Earth and the results could be catastrophic.
"This is really the first time we've tried to pull together an all-government preparedness strategy for dealing with this very serious natural disaster."
To get an idea of scale, the asteroid that is thought to have wiped out the dinosaurs was about 10 kilometers (about 6.5 miles) in diameter. An asteroid of this size would vaporize anything within about 100 miles of the impact site, inducing continent wide fire-storms and launching so much dust into the air that the skies would be black for months. After the acid rain storms and freezing temperatures of the impact winter subsided as the dust settled, the Earth would experience a ramped up greenhouse effect, with temperatures rising up to 10C (50 Fahrenheit) above their pre-impact levels.
On a long enough time frame, one of these massive asteroids will strike Earth, but for now, the more pressing concern are the millions of asteroids under 1 kilometer in size that are still large enough to cause regional or even continent-wide damage. Take the Chelyabinsk meteor that burst over Russia in 2013, for instance. Although only about 20 meters in diameter, the meteor burst released about 500 kilotons of energy, equivalent to about 25 of the atomic bombs dropped on Hiroshima, shattering glass in nearby buildings in the city of Chelyabinsk, and causing dozens of minor injuries from the fallout.
Fortunately, that one broke up in the atmosphere and didn't strike the Earth as a single mass, which would have made its impact even more devastating. According to the White House report, some 10 million objects larger than the Chelyabinsk meteor are thought to exist, but have not yet been detected.
"On average we do get an impact once a century or so that does do very severe harm," Johnson said, citing Chelyabinsk and the 1908 Tunguska impact. "It's a very rare event with very high consequences, but this will happen someday. There's no doubt about that."
Given the stakes, it's clear why NASA and the leading US defense and research agencies came together in January 2016 to form the Detecting and Mitigating the Impact of Earth-bound Near-Earth Objects (DAMIEN) working group to address the issues associated with killer asteroids. The DAMIEN group is behind the White House's new NEO strategy, and will be responsible for hashing out the specifics of the plan to save Earthlings from killer asteroids going forward.
"While it is highly unlikely that there will be a civilization-ending NEO impact over the next two centuries, the risk of smaller but still catastrophic NEO impacts is real," the report's authors write. "There is currently no whole-of government or international strategy to respond to such an even through all phases of a NEO impact scenario."
As I've previously reported for Motherboard, NASA's current plan for saving earth from killer asteroids is incredibly disorganized and underfunded. Indeed, until recently Johnson was the only person manning the entire Planetary Defense office at NASA.
Yet this is not to say that work hasn't been done. In 2005, Congress commissioned Spaceguard, an alliance of universities and observatories formally known as the Near-Earth Object Observation program, to find 90 percent of the estimated 500,000 NEOs larger than 140 meters by 2020. Although Spaceguard has found almost all of the NEOs in our solar system larger than 1 kilometer, overall it's only found about one-quarter of all the asteroids over 140 meters.
To assist in the search, the DAMIEN report calls for a space-based observatory dedicated to finding NEOs, which will work in cooperation with ground-based observatories. Since a telescope in space isn't limited by terrestrial weather conditions, it would greatly enhance Spaceguard's search capacity.
The only plans currently underway for a space-based NEO telescope are being carried out by the non-profit B612 foundation whose Sentinel telescope was supposed to launch last December, but has been delayed due to difficulties securing the requisite $450 million in funding required for the project. That $450 million may sound like a lot up front, but it pales in comparison to the cost of other space missions, and would be far less costly than the economic devastation resulting from a large asteroid impact.
NASA has also been considering the NEOCam, a space-based telescope that has received provisional funding for "detailed refinement." Unfortunately, during the latest round of budgeting for NASA's Discovery program, two other satellites were greenlit instead of NEOCam, but NASA said it would continue the asteroid-hunter's provisional funding, so there is still hope that NASA may go forward with a space-based NEO observatory in the future, especially in light of the recent White House strategy.
In tandem, the report also recommends updating the capabilities of ground-based NEO observatories by endowing them with more powerful planetary radars and improved spectroscopy instruments (this would allow for more accurate determinations of the composition of an asteroid).
But detection is only half the battle. In the event that an asteroid is found to be on an impact trajectory with Earth, NASA is also thinking about ways to deflect the killer asteroid. Some pretty far-out ideas have been proposed on this front, ranging from nukes in space to giant sun-powered lasers, but the most likely method is simply ramming into the asteroid to change its course.
This method will get its first proof of concept with NASA's Asteroid Impact and Deflection Assessment mission, which will involve ramming a satellite into an asteroid in 2020. AIDA was to be a joint mission with ESA, but at the latest ESA ministerial meeting, ESA's half of the mission couldn't find funding. This means that while NASA will still crash a satellite into an asteroid, there won't be a second satellite there to observe the impact and collect data about its effectiveness. Perhaps in light of this, the DAMIEN report recommends that, in addition to testing new deflection technologies, "deploying an instrumented means to measure deflection over time can provide assurance of mission success."
"Realistically, you'd need about 8-10 years advance warning to do something about an asteroid in space."
Finally, should all else fail, the report also considers what to do in an impact scenario. Although asteroid deflection is definitely possible given enough time, this requires a lot of advance warning. A recent joint exercise between NASA and FEMA ran a simulation in which there was only a four year advance warning of an impending asteroid impact. This might seem like a lot of time, but the simulation found that it wasn't enough time to launch a deflection mission—at best, NASA would be able to send a satellite to take pictures of the asteroid as it approached Earth. In many cases though, giant asteroids have passed uncomfortably close to Earth and astronomers weren't even aware of them until a few days in advance.
"There's the time needed to get the mission ready to go and launch it, the time it takes to get to the asteroid, and then the time needed for your deflection mechanism to have effect," said Johnson. "The amount of time needed to mount a robotic planetary mission is typically 5-6 years, so I'd say realistically, you'd need about 8-10 years advance warning to do something about an asteroid in space."
In light of this, the report recommends "a collaborative national approach" to NEO impact events, which would require improved information exchange among dozens of federal agencies. Additionally, this will require establishing NEO impact response and recovery procedures, which have yet to be determined, but would likely involve mass evacuations. Although FEMA and the Department of Homeland Security have catchall documents for responses to general catastrophes, the report recommends identifying the unique challenges that would be posed by an NEO impact rather than simply relying on these "all-hazards" documents.
"The next step is for there to be an action plan developed by DAMIEN as to what needs to be done to address this strategy," said Johnson. "It will get down into specifics of which agency will be doing what to address this strategy. This is just one in a series of these types of documents that have been put together for overall preparedness."
With newly-elected President Donald J. Trump set to take office on January 20, the fate of DAMIEN and the overall White House asteroid preparedness effort remains up in the air for now. But the latest report will serve as a starting point for any future efforts in asteroid impact preparedness.
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