You guys should wait until we lose contact with Voyager 1.
I have always found that thinking about the Voyager 1 and 2 and Pioneer 10 and 11 probes triggers powerful emotions in me and I've never been able to fully explain them or properly pin them down in text. The closest I've come is Lonely Photographer which I'll concede is almost as sophomoric as Munroe's effort. Let's cover Voyager 1 in particular.
Voyager 1 has been travelling away from the Earth for longer than most of the people reading this have been alive. It is expected to continue operating until the mid-to-late 2020s. It is the most distant man-made object from Earth. It takes our radio signals more than 15 hours to reach it, and it takes another 15 hours for Voyager's pathetically weak responses to return to us. That number is constantly increasing. But we will listen to those signals, for as long as there is still enough power to send them. This is because Voyager 1 is the only thing we have out that far. It is the human race's third of only five attempts to date to reach interstellar space. It is where no one and nothing has ever gone before. It is a space mission which will last a cumulative total of nearly fifty years.
Spirit is not far away. Spirit is not lonely. Spirit is local. We know precisely where it is. One day, we will visit Spirit in person, pick it up, brush off its dust and bring it home.
Voyager 1 is not coming home. Ever. It will outlive us. Once it stops transmitting, we will lose track of it, and we will never be able to find it again. Then, if we want to send another mission out that far, we will have to wait another half-century. It is the most important and most significant thing that humans have ever done, because it represents the width of the physical footprint that humans have made on the universe.