Q&A with Jamie Bock, principal investigator of NASA’s SPHEREx mission (members only)

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.

A week after two space probes from China and United Arab Emirates slipped into orbit around Mars, NASA’s $2.4 billion Perseverance rover, by far the most complex and ambitious of the three, will plunge into the red planet’s atmosphere Thursday for an automated white-knuckle descent.

In the final hours of its pioneering mission, NASA’s Cassini spacecraft opened its cameras to gaze down on Saturn, recording views of a nighttime cloudscape illuminated by sunlight reflected off countless tiny ice particles in the planet’s rings.