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

A Chinese spacecraft successfully touched down on the moon Tuesday, beginning what engineers have described as the most challenging phase of the mission to drill, scoop, and seal rocks for launch back into orbit later this week and return to Earth in mid-December.

Set to fly in its most powerful configuration with five solid rocket boosters, a United Launch Alliance Atlas 5 rocket rolled out to Cape Canaveral’s Complex 41 launch pad Tuesday in preparation for a planned blastoff two days later with a U.S. military communications satellite.

The U.S. Air Force has been unable to send commands to the service’s newest weather satellite for nearly a month, and engineers are trying to determine if the spacecraft can be salvaged, officials said last week.