Scientists believe a spacecraft could potentially catch up to the renowned interstellar comet 3I/ATLAS, which is rapidly moving away from Earth. By launching in 2035, a mission could reach this comet by 2085, approximately 732 astronomical units from the sun, which equals about 68 billion miles. For context, the farthest human-made object, Voyager 1, is currently about 170 AU away.
This ambitious mission would leverage the Oberth effect, a concept first introduced by rocket scientist Hermann Oberth in 1929. The principle is simple: a spacecraft gains speed as it approaches a massive body, like the sun. By firing its engines at its closest point, or periapsis, the spacecraft can achieve a significant increase in speed. T. Marshall Eubanks, a former NASA scientist, affirms, “Every launch benefits from the Oberth effect.” However, this mission proposes using the effect in a novel way, making a powerful engine burn during a flyby.
To achieve the needed speed of at least 5.1 miles per second, the spacecraft would have to come within 3.2 solar radii of the sun, or about 0.015 AU, risking exposure to extreme temperatures, potentially over 2,500°F. NASA’s Parker Solar Probe, which recently ventured within 0.04 AU of the sun, faced similar challenges but emerged successfully thanks to its advanced heat shield. Adam Hibberd, an engineer involved in the project, suggests that a comparable heat shield could safeguard a mission to 3I/ATLAS.
The mission path might involve a swing by Jupiter to slow down the spacecraft before heading back towards the sun. This method is essential because a spacecraft launched directly toward the sun would be too fast to get close. Instead of relying on multiple Venus flybys, which Parker Solar Probe used, this mission would make a single journey to Jupiter, cutting down the travel time significantly.
Hibberd and his team estimate the spacecraft would weigh about 1,100 pounds, comparable to NASA’s New Horizons mission. To support the ambitious maneuvers, they propose using several solid rockets to provide the necessary thrust at perihelion.
The speed at which the spacecraft reaches 3I/ATLAS depends on its delta-V during the solar Oberth maneuver. For instance, achieving a delta-V of 5.19 miles per second could allow a flyby in about 50 years. However, if the delta-V could rise to 6.43 miles per second, that timeframe shrinks to just 30 years—similar to the achievements of NASA’s Dawn spacecraft.
This raises an interesting question: Is pursuing 3I/ATLAS worth it? With the expected increase in discovered interstellar objects—thanks to advancements like the Rubin Observatory, which aims to identify about one new comet each year—there may soon be easier targets.
Despite this, there’s a fascination to explore 3I/ATLAS. In fact, Hibberd has expressed a preference for chasing 1I/’Oumuamua for its enigmatic properties, already drafting a mission plan called Project Lyra. Yet, timing is critical with interstellar objects moving faster than current vehicles can keep up with. Some experts, like Hibberd, argue that future missions could focus on capturing objects before they hurtle past us, eliminating the need for complex solar strategies.
Upcoming missions, like the European Space Agency’s Comet Interceptor set for 2028 or 2029, will wait for promising targets, allowing for direct exploration without chasing objects that are already speeding away.
While 3I/ATLAS moves further into space, the advancements in spacecraft trajectory planning signal exciting possibilities for exploring both familiar and distant celestial bodies in our solar system.
For more on this potential mission and the research behind it, you can find the pre-print on arXiv.
