Aquanauts Splash Down, Beginning NEEMO 21 Research Mission

The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21, 2016, as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, 62 feet below the surface of the Atlantic Ocean. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. via NASA

Sunset at the Viking Lander 1 Site

On July 20, 1976, at 8:12 a.m. EDT, NASA received the signal that the Viking Lander 1 successfully reached the Martian surface. This major milestone represented the first time the United States successfully landed a vehicle on the surface of Mars, collecting an overwhelming amount of data that would soon be used in future NASA missions. via NASA