A Russian cargo spacecraft has begun its brief journey to the International Space Station (ISS).
The robotic Progress 75 freighter, which is packed with nearly 3 tons (2.7 metric tons) of propellant, food and other supplies, launched atop a Russian Soyuz rocket from Baikonur Cosmodrome in Kazakhstan today (April 24) at 9:51 p.m. EDT (0151 GMT and 6:51 a.m. local Baikonur time on April 25).
If all goes according to plan, the Progress will reach the orbiting lab just a few hours from now, at 1:12 a.m. EDT (0512 GMT) on April 25. You can watch coverage of the Progress' arrival and docking operations live here at Space.com, courtesy of NASA TV, beginning at 12:30 a.m. EDT (0430 GMT).
The arrival will mark the start of a long-term stay for the Progress; it's expected to depart the ISS in December, NASA officials said. The freighter will therefore be on hand to help welcome SpaceX's Crew Dragon capsule on its first-ever crewed flight, the Demo-2 test mission.
Demo-2, which will carry NASA astronauts Bob Behnken and Doug Hurley to and from the orbiting lab, is scheduled to launch on May 27. It will be the first orbital human spaceflight to launch from U.S. soil since NASA's space shuttle fleet was retired in July 2011.
Progress is one of four robotic freighters that currently resupply the ISS, along with Japan's H-II Transfer Vehicle and two private American spacecraft, Northrop Grumman's Cygnus and SpaceX's cargo Dragon. (SpaceX holds both cargo and crew deals with NASA.)
Three of these four vehicles are disposable, burning up in Earth's atmosphere after they leave the orbiting lab. The exception is the reusable Dragon, which makes parachute-aided ocean splashdowns.
Three astronauts are living aboard the ISS at the moment: NASA astronaut Chris Cassidy, who commands the station's current Expedition 63, and cosmonauts Anatoly Ivanishin and Ivan Vagner.
- Space station's robotic cargo ship fleet (a photo guide)
- The top 10 Soviet and Russian space missions
- How SpaceX's Crew Dragon space capsule works (infographic)
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.