The interstellar comet 3I/ATLAS, discovered in 2025, is already leaving the Solar System at a speed of 61 km/s. Catching up with it by conventional means is almost impossible — it is too far away and too fast. However, astronomers and engineers from the Initiative for Interstellar Studies believe there is still a chance. It would require using an extremely risky technique — the Solar Oberth Maneuver (SOM) — and launching a spacecraft in 2035. In that case, by 2085 it could fly past the comet at a distance of 732 AU from the Sun (68 billion kilometers).

What the Oberth Maneuver Is and Why It Is Needed

The idea was proposed by Hermann Oberth in 1929. The principle is simple: the higher the spacecraft’s velocity at the moment its engines fire, the greater the increase in speed (delta-V). The maximum effect is achieved at perihelion — the point in the orbit closest to the Sun.

“Virtually every launch uses the Oberth maneuver. That is why, for example, Artemis 2 performs its trans-lunar injection burn at perigee rather than apogee. That is the Oberth maneuver. However, I have not found a single documented case of a pure Oberth maneuver of the type we are proposing — a powerful engine burn at the moment of closest approach to the Sun,” explained T. Marshall Eubanks, former NASA employee, now Chief Scientist at Space Initiatives Inc., and one of the authors of the study.

The Sun is the most massive body in the Solar System, so the maneuver provides the greatest velocity gain there. But to achieve the required delta-V (at least 8.4 km/s), the spacecraft must approach to just 3.2 solar radii from the center (0.015 AU). That is deep within the solar corona, where temperatures reach 1370–1400 degrees Celsius.

How to Reach Perihelion

A direct flight to the Sun is impossible — Earth already moves in orbit at 30 km/s, and the spacecraft would simply overshoot. It must first shed orbital velocity.

Parker Solar Probe accomplished this through seven Venus flybys over seven years. There is not enough time for that here — 3I/ATLAS is departing too quickly. The proposed plan is as follows:

Launch in 2035.
Fly to Jupiter (about one year).
Perform a gravity assist at Jupiter to reduce orbital speed.
Fall toward the Sun.
At perihelion, execute a powerful engine burn (Oberth maneuver).

For propulsion, the proposal includes several solid rocket boosters or even multiple Starship Block 3 vehicles with Raptor 3 engines, docked together in low Earth orbit.

What Kind of Protection Is Required

The spacecraft must withstand temperatures of 1400 degrees Celsius. The authors refer to a 2015 Keck Institute concept for an interstellar mission: a multilayer carbon composite heat shield with aerogel insulation. A similar shield was used by Parker Solar Probe — it survived 1370 degrees Celsius.

The spacecraft mass would be about 500 kg (similar to New Horizons), with a significant portion allocated to thermal protection. After the maneuver, it would become the fastest spacecraft in history — according to Eubanks, “by a wide margin.”

How Long the Flight Would Take

Everything depends on the delta-V achieved at perihelion:

8.36 km/s → flyby of 3I/ATLAS in 50 years (2085, at 732 AU from the Sun).
10.36 km/s → about 30 years.

For comparison, Voyager 1 has traveled only about 170 AU in nearly 50 years.

Is It Worth Chasing 3I/ATLAS?

The Vera Rubin Observatory is already operational and is expected to discover about one interstellar comet per year. Those would be easier to intercept — a spacecraft could be launched in advance and meet them near perihelion. ESA’s Comet Interceptor mission (launch planned for 2028–2029) is already waiting for a suitable target at the L2 point.

“For future interstellar objects, the Oberth maneuver is best avoided if possible. It is intended for chasing a specific object ‘after the bird has flown’ and is heading away from the Sun,” said Adam Hibberd, lead author of the study and developer of Optimum Interplanetary Trajectory Software.

Hibberd himself would prefer to fly to 1I/‘Oumuamua — it was far more mysterious. He has already developed a plan called Project Lyra, but the opportunity has passed.

Other Applications of the Maneuver

Even if 3I/ATLAS does not become the target, the Solar Oberth maneuver could be useful:

for missions to trans-Neptunian objects beyond Neptune;
to search for the hypothetical Planet Nine (290–800 AU);
to send a telescope to 550 AU, where the Sun’s gravitational lens would create an extremely powerful observing instrument.

In Brief

Scientists propose catching the departing interstellar comet 3I/ATLAS using a Solar Oberth maneuver: launch in 2035 → gravity assist at Jupiter → fall toward the Sun → powerful engine burn at perihelion at a distance of 3.2 solar radii. This would provide the required velocity boost. The flight would take 30–50 years. The maneuver is extremely risky (1400 degrees Celsius temperatures) but technically feasible — with protection similar to Parker Solar Probe. If not for 3I/ATLAS, this approach could be used for distant Solar System objects or future interstellar comets.