SpaceX launched an unpiloted Dragon cargo ship Friday loaded with 6,500 pounds of supplies and equipment bound for the International Space Station, including nearly a ton of research gear, samples and other material for some 50 different science investigations.

Running three days late because of bad weather, the Dragon's Falcon 9 booster roared to life at 6:05 p.m. ET, blasting off from pad 40 at the Cape Canaveral Space Force Station and arcing away to the northeast in line with the station's orbit.

Two and a half minutes after liftoff, the rocket's first stage, making its sixth flight, fell away and flew itself back to an on-target touchdown on a landing pad near the launch gantry. The second stage continued the climb to orbit, releasing the Cargo Dragon to fly on its own nine minutes and 20 seconds after launch. 

It was SpaceX's 638th Falcon 9 launch since the rocket's debut in 2010, the company's 56th such flight so far this year and its 611th successful booster recovery.

"This will be the first Cargo Dragon spacecraft to head to the station for a sixth time, so a great milestone there," said Bill Spetch, ISS operations integration manager at the Johnson Space Center. "We're sending over 6,000 pounds of hardware, supplies, science experiments and more to our Expedition 74 crew.

"This mission includes everything from water purification hardware to research that helps us better understand space weather," Spetch said. 

If all goes well, the Cargo Dragon will complete an automated rendezvous with the station early Sunday, moving in for docking at the front end of the forward Harmony module around 7 a.m.

Once hatches are opened, the spacecraft will be unloaded by Crew 12 commander Jessica Meir and her three crewmates, pilot Jack Hathaway, European Space Agency astronaut Sophie Adenot and cosmonaut Andrey Fedyaev.

Also on board the station as part of the seven-member Expedition 74 crew: Soyuz MS-28/74S commander Sergey Kud-Sverchkov, fellow cosmonaut Sergey Mikaev and NASA astronaut Chris Williams.

The Cargo Dragon is delivering more than 3 tons of equipment and supplies, including 1,363 pounds of crew clothing, food and other essentials; more than 1,000 pounds of vehicle hardware, 282 pounds of spacewalk components, 186 pounds of computer gear and 1,834 pounds of research equipment and samples.

"The ISS has enabled more than 4,000 different science experiments and technology demonstrations in its 25 years on orbit," said Liz Warren, deputy chief scientist for the space station program. "And that represents the work of over 5,000 researchers from 110 countries around the world.

"The International Space Station is a truly global endeavor. It serves both as a proving ground for scientific breakthroughs and as a critical stepping stone to help enable the Artemis program, lunar exploration and future Mars missions," Warren said.

The next major milestone for the space station program comes in July. Soyuz MS-29 commander Pyotr Dubrov, fellow cosmonaut Anna Kikina and NASA astronaut Anil Menon are scheduled to blast off from the Baikonur Cosmodrome in Kazakhstan on July 14. They will replace Kud-Sverchkov and his two Soyuz MS-28 crewmates.

Launch of a Russian Progress cargo ship is expected in early September, followed by the launch of NASA's Crew 13 — Jessica Watkins, Luke Delaney, Canadian astronaut Joshua Kutryk and cosmonaut Sergey Teteryatnikov — aboard a SpaceX Crew Dragon capsule on Sept. 12. They will replace Crew 12.

Three more cargo flights are expected before the end of the year, with crew rotation flights resuming in early 2027.