Farewell to Some Robotic Explorers

This image from Opportunity was the first picture I ever posted on this blog on Jan. 25, 2004.

The Opportunity Mars Rover was officially declared dead by NASA last week, after months of attempts to revive it from the effects of a global Martian dust storm. Fifteen years ago, Opportunity and its sister rover Spirit (lost several years ago) landed on Mars, each having a design life of 90 days, and began their scientific exploration. Over the years, the twin rovers revealed some fascinating information about Mars past and present, including evidence of ancient bodies of water on the surface.

NASA recently said goodbye to two other robotic explorers. The Kepler Space Telescope discovered thousands of exoplanets (planets that circle stars other than our Sun) while staring at just a tiny portion of the sky. The Dawn spacecraft explored two of the largest asteroids in the Solar System, contributing to knowledge of how the Solar System developed and of potential resources available in the asteroids. These three robotic explorers have completed, even exceeded, their missions and have paved the way for new explorers and eventual human expansion into space.