Asteroid Redirection: Current Abilities and Crucial Aims to Prevent Catastrophic Collision and Human Extinction
In the ongoing quest to protect our planet from potential asteroid impacts, various space agencies and organisations are working together to develop and implement defence strategies.
The NASA's Double Asteroid Redirection Test (DART) mission, launched in 2022, marked a significant milestone in this endeavour. The mission intentionally collided with a 160-meter-wide asteroid moonlet named Dimorphos, altering its orbit by 33 minutes. This breakthrough demonstrates the feasibility of asteroid deflection techniques.
More than 2,300 potentially hazardous asteroids (PHAs) larger than 140 meters have been identified through NASA's efforts. However, there are still many undiscovered threats, and the agency aims to achieve 90% completeness in NEO catalogs for objects larger than 140 meters by 2030, as outlined in NASA's 2023 Planetary Defense Strategy.
One of the key strategies for asteroid defence is focusing on non-fragmenting standoff blasts for nuclear options to minimise fallout risks. Other methods under development include gravity tractors, laser ablation, and ion beam shepherds, while nuclear options remain controversial but could potentially disrupt or deflect large threats.
The European Space Agency (ESA) is also involved in the development of asteroid defence strategies. The ESA's Ramses mission, set for launch in 2028, will rendezvous with Apophis during its 2029 Earth flyby, gathering data on this 370-meter PHA. The European Space Agency's Hera mission, launched in 2024, will conduct a detailed survey of the impact site in 2026, measuring Dimorphos's mass, composition, and subsurface structure.
China plans a kinetic deflection test on the 30-meter asteroid 2019 VL5 no earlier than 2025. The upcoming NEO Surveyor, an infrared space telescope set to launch in 2027, aims to detect 90% of NEOs larger than 140 meters within a decade.
Governments are encouraged to ratify international treaties for shared data and joint missions, involving NASA, ESA, JAXA, and CNSA to pool resources. Regular deflection tests are planned as part of NASA's strategy, but specific timelines or missions are not mentioned in this paragraph.
Integrating machine learning to predict orbits with 99% accuracy is proposed as a means to enhance detection networks. The Large Synoptic Survey Telescope (LSST), operational since 2025, scans the sky nightly, detecting NEOs down to 100 meters. However, only about 30% of PHAs larger than 140 meters are currently known.
CubeSats like those in Ramses offer low-cost, agile platforms for close-up reconnaissance, deploying instruments to map surface regolith and internal voids. Allocating at least 10% of global space budgets (~$5-10 billion annually) to planetary defence is proposed as a means to elevate planetary defence from experimental to operational.
Integration of AI for real-time threat assessment is a goal outlined in NASA's 2023 Planetary Defense Strategy. Ground-based telescopes funded by The Planetary Society's 2025 Shoemaker NEO Grants enhance detection accuracy, contributing to the global effort to safeguard Earth from asteroid impacts.
