Russian cosmonaut Anton Shkaplerov, (bottom); Japanese astronaut Norishige Kanai, middle; and U.S. astronaut Scott Tingle, above; wave prior to the launch of the Soyuz-FG rocket at the Russian-leased Baikonur cosmodrome in Kazakhstan on Sunday. Shamil Zhumatov/AP hide caption
The unmanned Antares rocket launched from Wallops Island, Va., on Sunday, carrying with it a Cygnus capsule containing some 7,400 pounds of supplies for astronauts at the International Space Station. Bill Ingalls/NASA/NASA via Getty Images hide caption
In this photo taken by Russian cosmonaut Sergey Ryazanskiy, the SpaceX Dragon capsule arrives at the International Space Station on Wednesday, stocked with scientific equipment, supplies — and ice cream. NASA via AP hide caption
"It's not just about making one German astronaut happy with fresh bread," Marcu explains. "There's really a deeper meaning to bread in space." Above, a photo illustration of bread in space. NASA/ Bake in Space GmbH hide caption
Flight engineer Kate Rubins checks out the Bigelow Expandable Activity Module, which is attached to the International Space Station. NASA hide caption
Astronaut Peggy Whitson became NASA's astronaut with the most time in orbit Monday. She is seen here earlier this year, along with fellow astronauts, in the Quest airlock of the International Space Station. AP hide caption
A Soyuz spacecraft carrying a new crew to the International Space Station, ISS, blasted off Thursday from the Baikonur cosmodrome in Kazakhstan. Dmitri Lovetsky/AP hide caption
NASA astronaut Kate Rubins floats in the International Space Station in September 2016, wearing a spacesuit decorated by patients recovering at the MD Anderson Cancer Center. NASA Johnson/Flickr hide caption
Trent Barton, a volunteer for the study looking at pressure inside the brain during space flights. Courtesy of David Ham hide caption
SpaceX's Dragon cargo ship is captured by astronauts aboard the International Space Station early Thursday, one day after its initial docking attempt was aborted. AP hide caption
This is what failed to happen on Wednesday morning. In this image from April 17, 2015, a robotic arm on the International Space Station grasps a SpaceX Dragon cargo ship during docking. NASA/AP hide caption
SpaceX's Falcon 9 rocket sits on the launch pad Saturday at Kennedy Space Center in Florida. SpaceX scrubbed the Saturday launch due to a technical issue. The company is tried again — and succeeded — on Sunday. Bruce Weaver/AFP/Getty Images hide caption
SpaceX's Falcon 9 rocket is prepared Friday for a launch at the Kennedy Space Center in Florida. Launch Pad 39A, one of the renovated space shuttle launch pads that SpaceX leases from NASA, has been the site of many of NASA's most famous liftoffs. Bruce Weaver/AFP/Getty Images hide caption
A Russian resupply rocket launched Thursday morning from Kazakhstan. The flight initially went as planned, but the rocket broke up in the atmosphere about six minutes after it took off. NASA TV hide caption