Tabletop Exercise Illuminates Gaps in Responding to Theoretical Asteroid Threats

NASA and other U.S. and international agencies participated in a tabletop exercise in April to work through how they might effectively respond to a potential asteroid threat. This fifth planetary defense tabletop exercise, or TTX-5, postulated a threat 14 years from now and discovered quite a few gaps. International participation was a key aspect of TTX-5 and figuring out the process for making decisions both domestically and internationally is one of them.

Planetary defense refers to defending Earth from asteroids and comets that might impact the planet and cause local, regional or global damage. NASA’s Planetary Defense Coordination Office (PDCO) in the Science Mission Directorate is in charge of U.S. efforts to locate and track Near Earth Objects (NEOs) to provide as much warning as possible and develop technologies to divert them like the 2022 DART mission.

NASA is part of an interagency team that looks at emergency response options if an impact with Earth can’t be avoided. The tabletop exercises are an opportunity to bring everyone together to practice hypothetical scenarios. For TTX-5, a particular focus was incorporating the international community. In addition to U.S. agencies like the Federal Emergency Management Agency (FEMA), the National Space Council, and U.S. Space Command, the European Space Agency and the space agencies of Canada, Germany, Japan and the United Kingdom participated as well as the United Nations Office of Outer Space Affairs (UNOOSA).

Today NASA published a “Quick Look” summary of the April 2-3, 2024 TTX-5 exercise held at the Johns Hopkins Applied Physics Laboratory in Laurel, MD. A more comprehensive “after-action report” will be released later this summer.

The summary lists 10 “high-level gaps” including that the process for making decisions has “not been adequately defined in the U.S. or internationally” and “mechanisms for timely international coordination of public messaging about asteroid impact threats have yet to be fully developed.”

During a media telecon this afternoon, NASA Planetary Defense Officer Emeritus Lindley Johnson said, however, that the “largest gap” is not knowing the whole population of asteroids that could pose threats.

Congress charged NASA with locating and tracking NEOs as far back as the 1990s starting with the largest — 1 kilometer or more in diameter — that could cause a global catastrophe. Scientists believe an asteroid that size impacted the Earth 65 million years aso and led to the extinction of the dinosaurs when debris billowed up into the atmosphere, blocking the Sun and changing the climate.

As directed, NASA located 90 percent of those big asteroids within 10 years. Congress’s next charge, in the 2005 George E. Brown Near-Earth Object Survey Act, was to find 90 percent of asteroids 140 meters or more in diameter. That poses a much greater challenge. Not only are they smaller, but their surfaces are dark. NASA is currently building a specialized space-based infrared telescope, NEO Surveyor, to accelerate the search. NASA hopes to launch it in 2027, although the agency’s official commitment is 2028.

Options for responding to an asteroid threat depend in large part on how much advance notice there is. TTX-5 postulated a 14-year warning period that could allow for sending one or more spacecraft to gain information about the asteroid’s composition before it gets here and aid in decision-making.

The group acknowledged that getting funding to launch probes could be a problem if the risk isn’t perceived as imminent, however, and FEMA’s Leviticus “L.A.” Lewis, who is on detail to PDCO, pointed out that FEMA deals with natural disasters on a daily basis. Something that wouldn’t happen for more than a decade might not get much attention. “For emergency management disaster responders, 14 years is a long time” and “figuring out where to put your resources to start working on this specific problem while still dealing with tornadoes and hurricanes etc. etc. is going to be a particular challenge.”

Another key element, Lewis stressed, is deciding who would be in charge. “Maybe the U.N. is the right place, but it may not necessarily be under the Office of Outer Space Affairs. That’s the biggest challenge for us right now, figuring out where that starts.”

These tabletop exercises are one step in that direction.