NASA

Today, NASA announced that the Kepler Space Telescope, which had been malfunctioning, will not be able to be repaired. Kepler may be used for other scientific operations, but its life as our country's planet hunter is effectively over, having successfully completed its prime mission.

Kepler, your mission was to find other Earths, places where life like us could exist somewhere beyond our blue world.

And you did. "Kepler has made extraordinary discoveries in finding exoplanets including several super-Earths in the habitable zone," John Grunsfeld, associate administrator for NASA's Science Mission Directorate said in the release announcing the end.

You were a new breed of NASA mission: cheap, targeted, and designed to answer just a few questions that we didn't even know to ask 30 years ago. How many planets are out there? How many planets like ours orbit other stars? How many chances have there been for some organic molecules to join up and start to live?

When the 20th century began, we did not know that we existed in one galaxy among many. As it closed, we had discovered the unfathomable vastness of the universe, but our living world was as unique as it had always been. We had barely begun to detect other planets, and they were huge and hot, places more likely to harbor liquid lead than liquid water.