Whatever name it sailed under — International Sun-Earth Explorer 3, and International Cometary Explorer, among others — this spacecraft has scored a number of firsts over the years, including the first comet flyby.
NASA Goddard Spaceflight Center
An image shot by NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite on Wednesday. It shows multiple wildfires in Calif. trailing smoke into the Pacific Ocean.
For helping to find asteroids, NASA has set up a contest with cash awards. In 2012, the agency said that "more potentially hazardous asteroids, or PHAs, are closely aligned with the plane of our solar system than previous models suggested."
People view the Northern Lights over Bamburgh Castle Beach Thursday in Northumberland, England. A powerful solar flare caused the aurora borealis to be visible farther south than usual.
Josh Maidwell/Barcroft Media/Landov