I was thinking about this earlier - what could we have done better to intercept this one? Because that's the only way we'll catch the next one...
Maybe wide-field Hubble-equivalents in the LaGrange points of the outer planets to help spot them on the way in? Ideally larger satellites with 25/50/100 years of cryogens available for long-duration missions? Although past a certain point your cryogen consumption would be constant - you're not getting heat from Sol, you're getting heat from your detectors/equipment... so a sunshield is useless.
Maybe wide-field Hubble-equivalents in the LaGrange points of the outer planets to help spot them on the way in? Ideally larger satellites with 25/50/100 years of cryogens available for long-duration missions? Although past a certain point your cryogen consumption would be constant - you're not getting heat from Sol, you're getting heat from your detectors/equipment... so a sunshield is useless.