Company founder Elon Musk says the Falcon 9 upper stage exploded when a high-pressure helium bottle broke loose and overpressurized the structure.

The large, heart-shaped feature on Pluto is a frozen plain rich in carbon monoxide.

A new image shows a strange formation on the surface of Pluto's moon Charon.

A roundup of this week's top aerospace and defense stories you may have missed.

Pluto has previously unsuspected mountains of water ice as high as the Rockies, while its moon Charon features spectacular canyons as much as 6 mi. deep.

LAUREL, Maryland — Pluto’s nitrogen-rich atmosphere appears to be leaking across open space to collect on at least one of the poles of the dwarf planet’s large moon Charon, according to scientists processing data the New Horizons probe sent to Earth shortly before its closest approach to the two bodies.

Mission managers now have settled in to wait for a brief signal Tuesday night that will let them know how the spacecraft fared in its intricately choreographed flyby.

Glen Fountain, New Horizons project manager at the Johns Hopkins University Applied Physics Laboratory, said Monday the spacecraft will hit its 60 x 90-mi. box “almost at the center of it” and right on time.