This artist’s concept depicts an asteroid drifting
through space. Many such objects frequently pass Earth. To help prepare for the
discovery of one with a chance of impacting our planet, NASA leads regular
exercises to figure out how the international community could respond to such a
threat.
NASA/JPL-Caltech
The fifth Planetary Defense Interagency Tabletop Exercise focused on an asteroid impact scenario
designed by NASA JPL’s Center for Near Earth Object Studies.
A large asteroid impacting Earth is
highly unlikely for the foreseeable future. But because the damage from such an
event could be great, NASA leads 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 being issued on
June 20.
Making such a scenario realistic
and useful for all involved is no small task. Scientists from the Center for
Near Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Southern
California, which specializes in the tracking and orbital determination of
asteroids and comets and finding out if any are hazards to Earth, have played a
major role in designing these exercises since the first 11 years ago.
“These hypothetical scenarios are
complex and take significant effort to design, so our purpose is to make them
useful and challenging for exercise participants and decision-makers to hone
their processes and procedures to quickly come to a plan of action while
addressing gaps in the planetary defense community’s knowledge,” said JPL’s
Paul Chodas, the director of CNEOS.
The Impact
Scenario
This year’s scenario: A
hypothetical asteroid, possibly several hundred yards across, has been
discovered, with an estimated 72% chance of impacting Earth in 14 years.
Potential impact locations include heavily populated areas in North America,
Southern Europe, and North Africa, but there is still a 28% chance the asteroid
will miss Earth. After several months of being tracked, the asteroid moves too
close to the Sun, making further observations impossible for another seven
months. Decision-makers must figure out what to do.
Explore
asteroids and near-Earth objects in real-time 3D
Leading the exercise was NASA’s Planetary Defense Coordination Office (PDCO), the Federal Emergency Management Agency Response
Directorate, and the Department of State Office of Space Affairs. Over the
course of two days in April, participants gathered at the Johns Hopkins Applied
Physics Laboratory in Laurel, Maryland, which hosted the event, to consider the
potential 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 planetary defense experts,” said Terik
Daly from APL, who coordinated the exercise. “An asteroid impact would have
severe national and international ramifications, so should this scenario play
out for real, we’d need international collaboration.”
Reality
Informs Fiction
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 the observations in
the months leading up to the exercise and used orbital determination
calculations to simulate the probability of impact.
“At this point in time, the impact
was likely but not yet certain, and there were significant uncertainties in the
object’s size 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 affected the decision-makers’ choices and how the
international community might respond to a real-world threat 14 years out.”
Options to
Deflect
Preparation, planning, and
decision-making have been key focal points of all five exercises that have
taken place over the past 11 years. For instance, could a reconnaissance
spacecraft be sent to the asteroid to gather additional data on its orbit and better
determine its size and mass? Would it also be feasible to attempt deflecting
the asteroid so that it would miss Earth? The viability of this method
was recently demonstrated by NASA’s Double Asteroid Redirection Test (DART), which impacted the asteroid moonlet Dimorphos on
Sept. 26, 2022, slightly changing its trajectory. Other methods of deflection
have also been considered during the exercises.
But any deflection or
reconnaissance mission would need many years of preparation, requiring the use
of advanced observatories capable of finding hazardous asteroids as early as
possible. NASA’s Near-Earth Object Surveyor, or NEO
Surveyor, is one such
observatory. Managed by JPL and planned for launch in late 2027, the infrared
space telescope will detect light and dark asteroids, including those that
orbit near the Sun. In doing so, NEO Surveyor will support PDCO’s objectives to
discover any hazardous asteroids as early as possible so that there would be
more time to launch a deflection mission to potential threats.
To find out the outcome of the
exercise, read NASA’s preliminary summary.
For more information about CNEOS, visit: https://cneos.jpl.nasa.gov/
Source: NASA Asteroid Experts Create Hypothetical Impact Scenario for Exercise - NASA
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