The crew of STS-131 returned home to Houston following their fifteen days in space aboard shuttle Discovery. * The first images are in from NASA’s Solar Dynamics Observatory, or SDO, and scientists who study the sun say they are a stunning treasure trove of data about Earth's star. * NASA helped celebrate Earth Day's fortieth anniversary with nine consecutive days of activities and public exhibits on the National Mall in Washington. * Robonaut 2, or R2, as it, or he, is also known, is scheduled to become the first human-like robot to take up permanent residence on the International Space Station. * Hundreds of students from middle schools, high schools, and colleges representing 20 states were in northern Alabama for the annual Space Launch Initiative, or LaunchFest. * The STS-130 crew paid a visit to NASA Headquarters where they played highlights of their February mission to the International Space Station for employees and guests. The six-astronaut crew of space shuttle Endeavour was commanded by George Zamka; Terry Virts was the pilot; Mission Specialists were Nicholas Patrick, Bob Behnken, Steve Robinson and Kay Hire. * On April 24, 1990, the Hubble Space Telescope launched aboard Space Shuttle Discovery from the Kennedy Space Center in Florida. Since then, the observatory orbiting 350 miles above Earth has produced hundreds of thousands of unprecedented images of different corners of the universe.