> I'm not sure capture would necessarily be all that likely. Assuming a flyby and not a crash, capturing a probe would require the captor to accelerate to the p

> I'm not sure capture would necessarily be all that likely. Assuming a flyby and not a crash, capturing a probe would require the captor to accelerate to the probe's relative velocity first. If you wanted to bring it back, too, you'd then have to decelerate back into a non-escape velocity with the captive in tow. This is a really good point. If you can make your probe fast enough you reduce warning time and make it very expensive to catch. > Energy from destruction tends not to be very organized. How would you use that energy for sending a coherent directed message that isn't even known in advance (assuming it would actually transmit some of the newly collected data and not just "bye bye")? I was assuming a signal that could not be distinguished from an explosion much like how cryptography can encrypt a message that without the key can not be distinguished from random noise. If one wanted to get really deniable about this you could just design a rock such that its shape and composition would reveal facts about the planets atmosphere based purely on how it explodes, e.g. the wave lengths of the light of an explosion vary based on oxygen content. If the rock doesn't explode on schedule you could conclude with some probability intelligent life intercepted it for study.