SpaceX's next Dragon cargo ship launch for NASA will lift off on April 21

NASA's next special delivery to the International Space Station has a launch date, but it's going to be one for early-birds.

A SpaceX Falcon 9 rocket will launch an uncrewed Dragon cargo ship packed with tons of supplies on Monday, April 21, from the historic Pad 39A of NASA's Kennedy Space Center in Cape Canaveral, Florida. Liftoff is set for 4:15 a.m. EDT (0815 GMT), making it a predawn launch.

"Along with food and essential equipment for the crew, Dragon is delivering a variety of experiments, including a demonstration of refined maneuvers for free-floating robots," NASA officials wrote in an announcement for the mission, called CRS-32. "Dragon also carries an enhanced air quality monitoring system that could protect crew members on exploration missions to the Moon and Mars, and two atomic clocks to examine fundamental physics concepts, such as relativity, and test worldwide synchronization of precision timepieces."

While NASA did not detail how much cargo will launch aboard the Dragon spacecraft, SpaceX resupply missions to the International Space Station (ISS) typically carry well over 2 tons of gear aboard. That includes experiment hardware, tools and spare parts, as well as food, water and other vital supplies.

SpaceX's resuable Dragon spacecraft and Falcon 9 rockets regularly fly cargo and crew rotation missions to the ISS for NASA. The Dragon capsules stay docked to the station for several months, then return to Earth to make an ocean splashdown, where they are recovered for future reflight.

SpaceX isn't the only U.S. company to fly cargo missions to the space station. Northrop Grumman's Cygnus spacecraft also hauls NASA supplies to the ISS, but that company had to cancel its next planned launch after the spacecraft was damaged during delivery to its Florida launch site. The next Cygnus launch is set for later this year in the fall. Russia's uncrewed Progress spacecraft also fly regular cargo trips to the station.