(CNN) -- Space shuttle Discovery launched early Monday to deliver spare parts and science experiments to the international space station.
Discovery launched at 6:21 a.m. ET from the Kennedy Space Center in Florida
Discovery, with its crew of seven astronauts, is carrying supplies and science equipment for the international space station's laboratories. The 13-day mission includes three planned spacewalks, replacing an ammonia tank assembly and retrieving a Japanese experiment from the station's exterior.
Discovery is scheduled to arrive at the space station on Wednesday, and return to Earth on April 18 at 8:35 a.m. ET.
After this mission, there are only three shuttle missions remaining before the space shuttle fleet is retired.
NASA said Discovery's mission will mark the first time four women have been in space at one time: Three women -- mission specialists Stephanie Wilson, Dorothy Metcalf-Lindenburger and Naoko Yamazaki -- comprise part of the Discovery's crew, while NASA astronaut Tracy Caldwell Dyson is already at the space station.
The launch comes three days after Russian spacecraft Soyuz TMA-18, carrying Dyson and Russian cosmonauts Alexander Skvortsov and Mikhail Kornienko, blasted off to the International Space Station from a Kazakhstan facility.
The space station, which orbits the Earth at a height of some 250 miles, is due to be finished next year and is about 90 percent complete.