Good morning. We have an exciting hearing today on NASA’s efforts to save the world—literally.
NASA’s Planetary Defense Coordination Office, or PDCO, leads the United States’ mission to safeguard the Earth from near-Earth objects, or NEOs—asteroids and comets that approach our planet. While most NEOs are harmless, those exceeding a certain size could cause catastrophic, even extinction-level impacts.
U.S. efforts to detect NEOs began in the 1990s, but a major initiative was passed as part of the 2005 NASA Authorization.
The George E. Brown Jr. Near-Earth Object Survey Act directed NASA to detect, track, and catalogue 90 percent of NEOs larger than 140 meters in diameter within 15 years. At that size, a NEO-Earth impact could cause significant regional destruction.
Nearly 20 years after the Act’s passage, only 44 percent of the estimated NEOs larger than 140 meters have been identified. Despite being five years past the original deadline, many potentially hazardous asteroids have yet to be found.
The world was starkly reminded of the importance of planetary defense in 2013, when a house-sized asteroid exploded over Russia. The blast released energy equivalent to about 440 kilotons of TNT—more than 30 times the force of the Hiroshima bomb—shattering windows, injuring thousands, and causing millions of dollars in property damage.
Because the asteroid approached from the direction of the Sun, it was undetectable by ground-based telescopes and went untracked. The resulting explosion caught the world entirely by surprise. In the aftermath, this Committee held a series of hearings to examine the risks posed by NEOs and assess NASA’s progress under the George E. Brown Jr. Act. Given recent events, we believe it is timely to continue those efforts today.
At the end of last year, NASA detected a new NEO that, at one point, had a 3.1 percent chance of impacting Earth in 2032. Subsequent observations have since lowered that risk well below one percent. Nevertheless, NASA’s ability to detect the asteroid with seven years of advance warning highlights important progress in NEO monitoring.
NASA has also made significant advances in testing mitigation technologies. In 2022, the agency’s Double Asteroid Redirection Test (DART) mission successfully collided with a small asteroid named Dimorphos, providing valuable data and proving that kinetic impact mitigation—or crashing a spacecraft into an asteroid—can effectively alter a NEO’s trajectory.
Finally, one of the most critical missions for planetary defense is NASA’s upcoming NEO Surveyor mission—the first space telescope dedicated solely to planetary defense. Scheduled to launch in the fall of 2027, NEO Surveyor will enhance detection of asteroids regardless of their darkness or proximity to the Sun, helping to close current detection gaps and meet the goals set by the Brown Act.
Today, we’ll revisit NASA’s approach to planetary defense—from discovering new NEOs to planning for potential interventions. We’ll also hear about the process for maintaining the NEO catalog, developing models and simulations, and calculating the likely impact consequences. Finally, we’ll discuss strategies for deflecting or disrupting a hazardous asteroid and the anticipated outcomes of such actions.
Protecting our planet from threatening asteroids and comets must be a top priority for NASA, and I look forward to hearing from our witnesses.