Not just identifying them, but also being able to catch them in time. They're coming in at solar escape velocities, and going out with same - and the odds of everything being aligned in such a way that we can take several years to do gravity assists are incredibly low.
> 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]
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.
Oh yeah, I don't think we're anywhere near "sample return" capability for an extra-solar object.
I doubt we're even near "impactor" capability, tbh. I think our best bet might be "catch up with something in the Oort somewhere around 2070, if we see something coming a decade ahead of time".
Never underestimate the ability of humans to throw something really hard ;)
I actually think if the object was on the right trajectory and we had enough time, that you could pretty much park an impactor in its path. You could probably do a lot of science based on the spectra of the resulting cloud.
I agree that gently landing and return a sample with that much delta V is out of our reach at this point. Maybe with enough shielding, you could park a second sample return vehicle in the path of debris.