The Kepler space observatory was launched in 2009 to find earth size exoplanets in the habitable zone (where liquid water is possible) of other stars in our galaxy. By 2015, 1,000 exoplanets had been discovered using the transition method, where small drops in a star's output indicate a planet blocking light. When two of its reaction wheels failed, the solar wind was used to stabilize it. Its new mission was designated "K2".
The design shows a small planet transiting a star, as in a multiple exposure. Beneath the name is its COSPAR designation. Kepler's four solar panels are arranged in a partial hexagon shape, when viewed from above, so I chose a hexagon for the patch outline. — Jim Leonardson