Russia's 30 Soyuz mission spacecraft is poised to lift off late Monday for the International Space Station with NASA astronaut Joe Acaba and cosmonauts Gennady Padalka and Sergei Revin.
Their Soyuz TMA-04M capsule is scheduled for launching from the Baikonur Cosmodrome on Monday at 11:01 p.m., EDT, or Tuesday at 9:01 a.m., local time.
The Russian State Commission that oversees Soyuz operations met early Monday to approve final preparations, a day after the booster was rolled to its launch pad by rail.
A successful launch will start the crew on a two day transit to the orbiting science laboratory. Their docking with the Russian segment Poisk module on Thursday at 12:39 a.m., EDT, will occur a little more than 48 hours ahead of the scheduled SpaceX launching of the first U.S. commercial re-supply mission to the ISS.
The newcomers will be greeted by Russia's Oleg Kononenko, the Expedition 31 commander, NASA's Don Pettit and Andre Kuipers of the European Space Agency.
Thursday's linkup will restore the station to six person operations for the first time since April 27, when American Dan Burbank and Russians Anton Shkaplerov and Anatoly Ivanishin returned to Earth in their Soyuz capsule, ending a 5 1/2 month mission.
Acaba, one of NASA's educator-astronauts, is a former Florida high and middle school science and math teacher, Marine Corps reservist, and U. S. Peace Corps volunteer. He is a veteran of a 2009 space shuttle station assembly mission.
Padalka, a Russian Air Force colonel, returns to command the space station for a third time, a first. Revin, a flight test engineer from NPO-Energia, is flying for the first time.
The 18-day, SpaceX Falcon9/Dragon mission is scheduled for launch from Cape Canaveral Air Force Station, Fla., on Saturday at 4:55 a.m, EDT.