Dear MESSENGER:

Our robotic space explorers have given us many wonders, and yet people tend to overlook them, being so focused on the drama of humans in space. Of course putting people in space has been amazing, and those courageous and skillful astronauts have done great work.

But our robotic spacecraft have revealed the solar system to us in ways that would have been impossible without them. They have skills and characters, they execute their instructions, they make mistakes their friends have to fix. They persevere against great odds. Like the world’s great cathedrals, they are infused with the spirt of the thousands of people who collaborated to make them. Surely that makes them one of civilization’s greatest achievements.

It’s also