Artist’s concept of the new spacecraft headed towards comet 3I/ATLAS (Image Credit: ESA).
In late 2025, astronomers discovered 3I/ATLAS, which turned out to be only the third rare visitor from beyond our Solar System ever discovered. It captured global attention, making its closest approach to Earth in December 2025. Now, scientists are exploring the idea of sending a spacecraft to chase the object into deep space, allowing us to study materials that originated from an entirely different star system.
A breathtaking view of comet 3I/ATLAS as it left the Solar System in late 2025 (Image Credit: Dan Bartlett).
This proposed concept would rely on a physics trick named the “Oberth effect”, which was first created in 1929 by Austro-Hungarian rocket scientist Hermann Oberth. His idea was to give a spacecraft an enormous boost in velocity by swinging it close to a massive gravitational well, like a planet or star. In the case of 3I/ATLAS, the probe would swing very close to the Sun before starting its booster rockets, which if launched in 2035, would allow it to gain enough energy to catch up to the comet by 2085.
A diagram showing the orbit of the comet, with its minimum distance to Earth having happened at 170 million miles (Image Credit: NASA/JPL-Caltech).
Even in this case, the meeting would happen very far from home. In total, scientists are predicting the meetup would happen over 730 AU (1 AU being the distance from Earth to the Sun), away, or roughly 68 billion miles. For reference, the farthest spacecraft ever launched, nearly half a century ago, was Voyager 1. It is currently only about 170 AU from the Sun. Reaching 3I/ATLAS would require the spacecraft to travel both faster and farther than any mission ever before it.
Artist’s concept of a spacecraft passing close to the radiating Sun, a necessary maneuver for the probe in order to catch 3I/ATLAS (Image Credit: NASA).
With the scientific excitement over 3I/ATLAS’s discovery came a wave of speculation in the general public. Because it was discovered months before its closest approach to Earth and the Sun, astronomers had much more time to analyze it than they did with the two previous interstellar comets. However, during that same period, a U.S. government shutdown temporarily limited NASA’s communications, which caused social media to flood with claims that the comet was actually alien technology.
As scientists collect more data, it’s as clear as ever that 3I/ATLAS is a normal comet from another star system. Astronomical observations of its icy surface indicate gases escaping, and measurements of its motion as it approached the Sun matched the expected behavior of previously observed comets. While 3I/ATLAS may not be extraterrestrial technology, it certainly offers invaluable clues about the chemistry, physics, and formation of planets beyond our familiar eight worlds. For that reason, chasing down this comet remains a tantalizing possibility.