Intercepting 3I/ATLAS at Closest Approach to Jupiter with the Juno spacecraft

Abstract

The interstellar object 3I/ATLAS is expected to arrive at a distance of $53.56(\pm 0.45)$ million ${\rm km}$ ($0.358\pm 0.003$~au) from Jupiter on March 16, 2026. We show that applying a total thrust $Δ$V of $2.6755 {\rm km~s^{-1}}$ to lower perijove on September 9, 2025 and then execute a Jupiter Oberth Maneuver, can bring the Juno spacecraft from its orbit around Jupiter to intercept the path of 3I/ATLAS on March 14, 2026. We further show that it is possible for Juno to come much closer to 3I/ATLAS ($\sim{27}$ million km) with 110 kg of remaining propellant, merely 5.4% of the initial fuel reservoir. We find that for low available $Δ$V there is no particular benefit in application of a double impulse (for example to reach $\sim{27}$ million km from 3I/ATLAS), however if Juno has a higher $Δ$V capability there is significant advantage to a second impulse with typically a saving of propellant by a factor of a half. A close fly-by might be able to probe the nature of 3I/ATLAS far better than telescopes on Earth.