Finding Asteroids Before They Find Us
NASA’s Planetary Defense Program
Kelly Fast
Acting Planetary Defense Officer
NASA Planetary Defense Coordination Office
About the Lecture
NASA’s planetary defense program addresses one of the few natural hazards that can, in principle, be predicted years in advance and prevented: the impact of a dangerous near-Earth asteroid or comet. At the center of that effort is NASA’s Planetary Defense Coordination Office, established in 2016 to manage the agency’s work to find, track, characterize, and, when necessary, help develop options to mitigate hazardous near-Earth objects. Through its Near-Earth Object Observations Program, the office helps turn astronomical observations into practical risk assessment and response planning.
This lecture will describe how planetary defense has become an international enterprise as well as a national one. NASA’s coordination role extends beyond U.S. agencies to the International Asteroid Warning Network, which shares observations and threat information worldwide, and the Space Mission Planning Advisory Group, which brings together space agencies to examine possible reconnaissance and deflection responses. Both entities are endorsed by the United Nations. In that sense, planetary defense is not only a scientific and engineering challenge, but also a problem in global communication, informed decision-making, and preparedness.
The talk will also examine how these systems perform when a real object draws attention. The recent case of asteroid 2024 YR4 briefly raised concern because early calculations showed a small chance of Earth impact, before additional observations ruled out any significant Earth risk. NASA has described this episode as an example of how the planetary defense community refines risk as additional data arrive. It illustrated the importance of rapid orbit determination, transparent public communication, and it established channels for notifying governments and international bodies when a credible threat must be assessed.
Finally, the lecture will show that planetary defense is no longer limited to watching the sky. It now includes tested methods for changing an asteroid’s motion. NASA’s Double Asteroid Redirection Test was the first mission to demonstrate asteroid deflection by kinetic impact, and NASA’s planned NEO Surveyor mission is the first space telescope specifically designed to discover and characterize asteroids and comets that may pose a hazard to Earth. Together, these efforts contribute toward a strategy with two essential goals: discover hazardous objects as early as possible, and ensure that humanity has credible response options before an impact threat is discovered.
NASA Planetary Defense Coordination Office: https://science.nasa.gov/planetary-defense/
NASA Center for Near-Earth Object Studies: https://cneos.jpl.nasa.gov/
NASA page on asteroid 2024 YR4: https://science.nasa.gov/solar-system/asteroids/2024-yr4/
NASA DART mission: https://science.nasa.gov/mission/dart/
NASA NEO Surveyor mission: https://science.nasa.gov/mission/neo-surveyor/
International Asteroid Warning Network: https://iawn.net/
Space Mission Planning Advisory Group: https://www.cosmos.esa.int/web/smpag
United Nations Office for Outer Space Affairs, near-Earth objects: https://www.unoosa.org/oosa/en/ourwork/topics/neos/index.html
About the Speaker
Kelly E. Fast is Acting Planetary Defense Officer in NASA’s Planetary Defense Coordination Office at NASA Headquarters, where she also oversees the Near-Earth Object Observations Program, and NASA’s role in the International Asteroid Warning Network. Previously, she managed NASA’s Near-Earth Object Observations Program, as well as leading several research programs in NASA’s Planetary Science Division, and serving as Program Scientist for the MAVEN mission to Mars. Kelly has also been a visiting astronomer at NASA’s Infrared Telescope Facility on Maunakea and contributed to management activities involving both the IRTF and NASA’s participation in the Keck Observatory.
Kelly’s research has centered on planetary atmospheres, planetary defense, and the observational study of small bodies in the solar system. She worked with very high spectral resolution infrared instrumentation, including HIPWAC, to investigate ozone and atmospheric chemistry on Mars, atmospheric dynamics on Titan, and the atmospheric consequences of impact events on Jupiter.
Among notable aspects of her work, Kelly helped lead NASA’s programs for finding, tracking, and characterizing near-Earth objects, coordinated US and international planetary defense activity through NASA and the International Asteroid Warning Network, and played key programmatic roles connected to a variety of NASA missions and observing campaigns. She also contributed to important work on Martian ozone, Titan’s winds and composition, and Jupiter’s stratospheric response to impact events.
Among other honors and awards Kelly received NASA Headquarters Honor Awards for exceptional performance in management, operations, and the success of the Planetary Defense Coordination Office in detecting and warning of natural impact hazards to Earth. She has also been honored by the naming of main-belt asteroid 115434 Kellyfast in recognition of her contributions to planetary science.
Kelly earned a BS degree in Astrophysics at the University of California, Los Angeles, and an MS and PhD in Astronomy at the University of Maryland, College Park.