Four astronauts are on their way to the International Space Station aboard a rocket that's been there before.
Americans Shane Kimbrough and Megan McArthur are on their way to a six-month space station mission, along with astronauts from France and Japan. Their Falcon rocket carried a crew to the space station in November. This morning's launch was delayed on Thursday because of poor weather offshore from the Kennedy Space Center.
A prime focus of the astronauts' mission will be to study "tissue chips," or "small models of human organs containing multiple cell types that behave much the same as they do in the body" and that NASA hopes will advance the development of drugs and vaccines, according to the space agency, CNN reports.