The Rosetta probe had to fly-by several bodies to acquire the necessary velocity to match 67P/Churyumov–Gerasimenko (Chury). Towards this end it was launched almost a decade in advance. Philae will fire a pair of harpoons to anchor itself to the comet.
Thinking aloud - between them, Rosetta and Philae mass around 192 kg. Chury's mass is 3.14×10^12± 0.21×10^12 kg
Call this a thought-experiment ...
Say now Rosetta were to be launched shortly before Chury were at a suitable rendezvous. (As contrasted to 10 years in advance.)
Say further Rosetta were to cold-fire a pair of harpoons to intercept Chury. The harpoons could be attached to a winch aboard Rosetta to reel the craft in towards the comet.
- Could Rosetta have lassoed Chury, and hitched a ride instead of spending 10 years to match velocity, and orbit?
- How much force would such a tether/lasso experience?
- Is any material produced by our contemporary technology capable of withstanding this force whilst being light enough to be launched into deep-space?
PS: The draw-back of the lasso method is it's touch-and-go nature. On the other hand, it may have the potential to afford a relatively
quick study for any target-of-opportunity.