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

A senior NASA official said Monday the agency could select two new robotic planetary science missions next year for launch in the early 2020s, and the five finalists favor Venus and asteroid research.

NASA’s Cassini orbiter sailed through the tenuous outermost reaches of Saturn’s atmosphere without trouble Monday, performing the first of five close swings nearer to the planet than any previous spacecraft before a final dive Sept. 15 to end the probe’s nearly 20-year mission.

Two U.S. Air Force cargo planes delivered the Mars 2020 rover, cruise stage, descent module and the Mars Helicopter to the Kennedy Space Center in Florida this week for final assembly, fueling and mounting atop a United Launch Alliance Atlas 5 rocket in preparation for liftoff in July.