For eight years, the only way NASA’s astronauts could get to the ISS has been via the Russian Soyuz rocket.
There are several different supply vessels (the Japanese Kounotori, the SpaceX CRS, Northrop Grumman Cygnus, the Russian Progress craft) but there’s only been one human-mover.
This year, NASA will obtain access to two manned craft, the SpaceX Crew Dragon and the Boeing Starliner, as part of its Commercial Crew Development program.
The Starliner will have a run without crew in March 2019, followed by a manned run in August. The Crew Dragon will have its unmanned run in February, with a manned launch softly scheduled in June.
Each craft can carry seven people, and is reusable. The Dragon is somewhat lighter and it is surprising how different the designs are, with the Dragon looking rather like an old torpedo and the Starliner more like the Apollo Command module. Starliner will land on dry ground, Dragon uses a splashdown. Dragon also has side-mounted launch escape rocketry.
The crew for the first Boeing Starliner launch has already been named, and it includes two NASA astronauts and one retired NASA astronaut who is now a Boeing employee. The inaugural Crew Dragon flight will have two crew, both of them current NASA astronauts.
Although the ISS ferry run will be the bread and butter for both of these craft, there have also been plans for their use in space tourism.
