Q&A with Marc Rayman, chief engineer on NASA’s Dawn mission (members only)

NASA has narrowed its choices for a new billion-dollar robotic space mission: A plutonium-powered quadcopter to explore the hazy landscape of Saturn’s largest moon Titan, or a probe to scoop up a piece of a comet and return it to Earth.

In the first official weather outlook the planned launch this week of NASA’s Mars 2020 Perseverance rover, meteorologists predict an 80 percent chance of favorable conditions to allow liftoff of an Atlas 5 rocket from Cape Canaveral Thursday.

NASA’s senior manager in charge of the development of the James Webb Space Telescope, Eric Smith, recently spoke with Spaceflight Now about the decision to reschedule its launch from October 2018 to the spring of 2019.