Nineteen hours after launching, two NASA astronauts will arrive at the International Space Station.
On Saturday, two NASA astronauts, Robert L. Behnken and Douglas G. Hurley, were launched into orbit atop a SpaceX rocket. It was the first time the private company, founded by the billionaire Elon Musk, had ever launched humans into space. It was also the first time since 2011, when NASA retired its space shuttles, that astronauts had lifted off for the International Space Station from American soil.
Mr. Behnken and Mr. Hurley’s trip required a 19-hour trip around the planet as the spacecraft they were traveling in steadily caught up with the orbital outpost. Their capsule, the SpaceX Crew Dragon, is scheduled to dock at the space station at 10:29 a.m. Eastern time on Sunday. NASA Television is providing ongoing coverage of the trip to the space station.
The space station, at an altitude of about 250 miles, zips around Earth at more than 17,000 miles per hour. The fundamental principle of orbital dynamics is that objects in lower orbits move faster, and those in higher orbits move slower.
At launch, the Crew Dragon started out trailing the space station. But traveling in an orbit below the space station, it was moving faster and catching up. Through a series of maneuvers, the capsule raised its orbit, allowing the capsule to approach the station at a lower speed.
While the astronauts could dock with the station manually in an emergency, the Crew Dragon’s computers will automatically begin the capsule’s close approach to the space station at about 8:27 a.m., when it is about 4.5 miles away.
