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Astronomy and space

Astronomy and space

US calls for asteroid-impact plan

22 Jun 2018
while asteroid impacts have a very low likelihood of happening, they could cause a lot of damage if they were to occur
Danger from above: while asteroid impacts have a very low likelihood of happening, they could cause a lot of damage if they were to occur. (Courtesy: iStock/PaulPaladin)

International cooperation must be improved to prepare for potential strikes by near-Earth objects (NEOs). That is one recommendation of a new report by a group of US government agencies that outlines methods to deal with asteroids and comets that pass within 50 million kilometres of Earth.

The report – National Near-Earth Object Preparedness Strategy and Action Plan – provides an approach to develop technologies, policies, practices, and procedures for US and global vulnerability to NEO impacts. It sets out five specific goals, which include NASA improving its ability to detect, track and characterize NEOs. Those actions, say the 20-page report, should reduce the current levels of uncertainty about potential strikes on Earth and help the development of more accurate modelling and more effective decision-making.

An asteroid impact scenario is a low-probability but a high-consequence event

Leviticus Lewis

Another goal involves NASA and other agencies developing simulation tools to improve the modelling and prediction of NEOs. The report also calls on NASA to develop fast-response reconnaissance missions and technologies for deflecting or disrupting potentially hazardous NEOs. The final two recommendations are for increased international cooperation and a strengthening and routine practice of emergency procedures for dealing with NEO impacts.

NASA officials and other agencies emphasise that, while such impacts have a very low likelihood, they could cause a lot of damage if they were to occur. “We recognize that an asteroid impact scenario is a low-probability but a high-consequence event,” says Leviticus Lewis of the Federal Emergency Management Agency. “An asteroid impact scenario is a unique emergency and may be just different enough that some degree of preparedness specific to this threat is necessary.”

Lindley Johnson from NASA’s planetary defence office says that implementing the plan will “greatly increase our nation’s readiness and work with international partners to effectively respond should a new potential asteroid impact be detected”.

The report, however, does not provide any specific funding for the actions it recommends. “Most of the actions we’re calling for are things that can be done within existing resources that are already allocated,” says Aaron Miles of the White House Office of Science and Technology Policy. “This is more about figuring out how to use those resources smartly and do so in a coordinated and cooperative way across the US government.”

Peter Gwynne is Physics World’s North America correspondent

Analysis: More needs to be done to study possible impact scenarios

Monitoring near-Earth objects (NEOs) is hardly a new pursuit. NASA has studied them for almost five decades and in the late 1990s the agency expanded its effort by creating a project called Spaceguard to specifically search for them. Since then, several dozen have passed between Earth and the Moon.

The importance of planning for such events was evident on 15 February 2013 when the Chelyabinsk meteor – a 20 m-wide asteroid – exploded over Russia. Its shock wave damaged more than 7000 buildings and indirectly caused about 1500 people to seek medical care. Indeed, the event created the largest explosion on the planet since the one that occurred over the Tunguska river in Siberia in 1908, entering the atmosphere with a mass of 13,000 tonnes.

US congressional hearings following the event led to NASA and other agencies speeding up their plans for effective asteroid detection. Later that year, the space agency rebooted its then dormant Wide-Field Infrared Survey Explorer to begin a three-year mission to search for NEOs and in 2016 NASA created its Planetary Defense Coordination Office to detect, monitor, and characterize all NEOs.

While much work has been focused on characterizing NEOs, more needs to be done to understand how to deal with potentially threatening bodies. In 2015, NASA and the European Space Agency came together to work on the Asteroid Impact and Deflection Assessment (AIDA) mission. This involved two craft travelling to a binary asteroid system called Didymos. One probe, built by ESA and called AIM, would study the composition of the asteroids, while the other – dubbed the Double Asteroid Redirection Test (DART) – would impact into it. Once DART fired into the asteroid, AIM would have studied how the body was affected.

Yet following budget issues, ESA cancelled AIM leaving NASA to go it alone. That means that the asteroid impact of DART, once it arrives at the asteroid in 2022, will be monitored from ground-based telescopes and radar rather than a dedicated mission. ESA is, however, planning to send a mission to Didymos that will arrive three years after DART has impacted.

The report is a timely reminder that dealing with NEOs should be an international endeavour and not just the responsibility of NASA.

Michael Banks is news editor of Physics World magazine

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