In this image provided by NASA, SpaceX astronauts are greeted by those already aboard the International Space Station after the Dragon capsule successfully docked on Saturday. Their arrival brings the total number of astronauts on the station to a recent high of 11. NASA via AP hide caption
The International Space Station is larger than a football field. But with 11 people soon to be aboard, there aren't enough places for them all to sleep. Courtesy NASA hide caption
Astronauts (from left) Victor Glover, Michael Hopkins, Shannon Walker and Japan's Soichi Noguchi wave to family and friends as they leave for the launch site on Sunday. John Raoux/AP hide caption
From left, astronaut Soichi Noguchi of Japan and NASA astronauts Shannon Walker, Victor Glover and Michael Hopkins walk after arriving at Kennedy Space Center in Cape Canaveral, Fla. The four astronauts will fly on the SpaceX Crew-1 mission to the International Space Station scheduled for launch on Saturday. Terry Renna/AP hide caption
Northrup Grumman's Antares rocket lifts off from the NASA Wallops test flight facility in Virginia on Oct. 2. The rocket was scheduled to deliver supplies to the International Space Station. Thom Baur/Northrup Grumman/AP hide caption
NASA astronaut Kate Rubins participates in Soyuz qualification exams on Wednesday at the Gagarin Cosmonaut Training Center just outside Moscow. Andrey Shelepin/AP hide caption
The mouse on the right has been engineered to have four times the muscle mass of a normal lab mouse. A drug to achieve the same effect was recently tested in space. Se-Jin Lee/PLOS One hide caption
The SpaceX capsule sits aboard a recovery ship in the Gulf of Mexico. NASA/Screenshot by NPR hide caption
NASA astronauts (from left) Bob Behnken, Doug Hurley and Chris Cassidy are the U.S. members of the Expedition 63 crew aboard the International Space Station. Behnken and Hurley are scheduled to return to Earth on Aug. 2. NASA hide caption
SpaceX's Crew Dragon capsule approaches the International Space Station ahead of docking Sunday. NASA / NASA TV hide caption
NASA astronaut Doug Hurley rehearses putting on his SpaceX spacesuit last week at the Neil A. Armstrong Operations and Checkout Building at Kennedy Space Center in Florida. Kim Shiflett/NASA hide caption
A SpaceX Falcon 9 rocket carrying more than 4,300 pounds of science and research, crew supplies and vehicle hardware to the International Space Station launches from pad 40 at Cape Canaveral Air Force Station in Florida. This is the final flight of SpaceX's first-generation Dragon cargo capsule. SOPA Images/SOPA Images/LightRocket via Gett hide caption
This photo provided by NASA shows the view from NASA's Andrew Morgan's helmet cam as Italian astronaut Luca Parmitano works outside the International Space Station during a spacewalk Saturday. AP hide caption