[adolph]

> odds of everything being aligned in such a way that we can take several years to do gravity assists are incredibly low.

Project Lyra develops concepts for reaching interstellar objects such as 1I / 'Oumuamua and 2I / Borisov with a spacecraft, based on near-term technologies. [0]

Several technology options are outlined, ranging from a close solar Oberth Maneuver using chemical propulsion, and the more advanced options of solar and laser sails. [1]

0. https://i4is.org/what-we-do/technical/project-lyra/

1. https://arxiv.org/abs/1711.03155

[XorNot]

It occurs to me since survivability isn't a problem for an unmanned probe, that a "cold" nuclear thermal engine vehicle could be used as a loitering interceptor: get it a solar orbit, and leave it till you see a target, then accelerate up to extra-solar escape velocity.

It solves the disposal problem neatly, since the probe and reactor are both leaving the solar system forever afterwards.