The Fifth Planetary Defense Interagency Tabletop Exercise focused on an asteroid impact scenario designed by NASA JPL’s Center for Near Earth Object Studies.
It is highly unlikely that a large asteroid will hit Earth in the near future. But because the damage from such an event could be extensive, NASA conducts hypothetical asteroid impact “tabletop” exercises every two years with experts and decision makers from federal and international agencies to address the many uncertainties of an impact scenario. The most recent exercise took place this past April, with a preliminary report released on June 20.
Making such a scenario realistic and actionable for all involved is no easy task. Scientists at the Center for Near Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Southern California, which specializes in tracking and determining the path of asteroids and comets and determining whether they pose a threat to Earth, have played a key role in designing these exercises since the first one 11 years ago.
“These hypothetical scenarios are complex and require a lot of effort to design. Our goal is to make them useful and challenging for exercise participants and decision makers so they can hone their processes and procedures to quickly arrive at a plan of action while addressing gaps in knowledge across the planetary defense community,” said JPL’s Paul Chodas, director of CNEOS.
This year’s scenario: A hypothetical asteroid is discovered, possibly several hundred meters in diameter, with an estimated 72% chance of hitting Earth within 14 years. Possible impact sites include densely populated areas of North America, southern Europe, and northern Africa, but there is still a 28% chance the asteroid will miss Earth. After several months of tracking, the asteroid moves too close to the sun, making further observations impossible for the next seven months. Decision makers must figure out what to do.
The exercise was led by NASA’s Planetary Defense Coordination Office (PDCO), the Federal Emergency Management Agency Response Directorate, and the Department of State’s Office of Space Affairs. For two days in April, participants gathered at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, where the event took place, to consider possible national and global responses to the scenario.
“This was a very successful tabletop exercise, with nearly 100 participants from U.S. government agencies and, for the first time, international experts in planetary defense,” said Terik Daly of APL, who coordinated the exercise. “An asteroid impact would have serious national and international consequences, so if this scenario were to happen, we would need international cooperation.”
In real life, CNEOS calculates the orbit of every known near-Earth object to provide assessments of future potential impact hazards in support of NASA’s planetary defense program. To make this scenario realistic, the CNEOS team simulated all observations in the months leading up to the exercise and used orbital calculations to simulate the probability of impact.
“At this point, the impact was likely but not certain, and there were significant uncertainties about the size of the object and the impact location,” said Davide Farnocchia, a navigation engineer at JPL and CNEOS who led the design of the asteroid’s orbit. “It was interesting to see how this influenced the decisions of decision makers and how the international community might respond to a real threat 14 years from now.”
Preparation, planning and decision-making were key focuses of all five exercises that have taken place over the past 11 years. For example, could a reconnaissance spacecraft be sent to the asteroid to gather additional data about its orbit and better determine its size and mass? Would it also be feasible to attempt to deflect the asteroid so that it would miss Earth? The feasibility of this method was recently demonstrated by NASA’s Double Asteroid Redirection Test (DART), which struck the asteroid moon Dimorphos on September 26, 2022, slightly altering its orbit. Other deflection methods have also been considered during the exercises.
But any deflection or reconnaissance mission would take years of preparation, requiring sophisticated observatories that can find dangerous asteroids as early as possible. NASA’s Near-Earth Object Surveyor, or NEO Surveyor, is one such observatory. The infrared space telescope, operated by JPL and scheduled for launch in late 2027, will detect bright and dark asteroids, including those orbiting near the sun. In doing so, NEO Surveyor will support PDCO’s goal of discovering dangerous asteroids as early as possible, allowing more time to launch a deflection mission toward potential threats.
For the outcome of the exercise, please read NASA’s preliminary summary.
For more information about CNEOS, visit:
https://cneos.jpl.nasa.gov/
Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, California.
818-354-2649
ian.j.oneill@jpl.nasa.gov
Karen Vos / Charles Blauw
NASA Headquarters
202-358-1600 / 202-802-5345
karen.c.fox@nasa.gov / charles.e.blue@nasa.gov
2024-095