Q&A with Scott Bolton, principal investigator on NASA’s Juno mission

This photo gallery shows the U.S. Navy’s fourth Mobile User Objective System communications satellite, already encapsulated in the 18-foot-diameter nose cone, being lifted atop the United Launch Alliance Atlas-Centaur rocket last week at the Vertical Integration Facility.

Ground crews finished the initial build-up of the last “single stick” medium-lift variant of United Launch Alliance’s Delta 4 rocket on its launch pad at Cape Canaveral last week in preparation for liftoff with a GPS navigation satellite July 25.

A review of data captured by NASA’s Galileo spacecraft as it orbited Jupiter in the 1990s indicates it likely flew through a plume of water vapor spewing from cracks in the surface of the moon Europa, providing independent evidence water is being released from a vast sub-surface ocean beneath its frozen crust, scientists said Monday.