"We are on the brink of launching American astronauts on American rockets from American soil", said NASA Administrator Jim Bridenstine during the "Launch America" announcement. One is to keep US astronauts aboard ISS longer than the typical 4-6 month missions.
NASA has worked closely with the companies throughout design, development and testing to ensure the systems meet its safety and performance requirements.
For SpaceX's first flight to the ISS, the NASA crew will be Victor Glover on his first space flight and Mike Hopkins, who spent 166 days in space as part of Expedition 37/38. Once the spacecraft is attached to the space station, it's created to stay there for 210 days.
Earlier this year, NASA unveiled a commercial crew schedule that called for the first uncrewed test flights by SpaceX and Boeing this month.
Nicole Mann: Mann was chosen as an astronaut in 2013, coming to NASA from the Marine Corps, where she was a Lieutenant Colonel and a test pilot.
Since 2010, that program has inched along, moving ever-closer to crewed and uncrewed test flights.
The first Starliner post-certification mission, yet to be formally scheduled, will fly NASA astronauts Josh Cassada and Sunita Williams.
A recent mission abort by Boeing resulted from leaking engine fuel, and USA astronauts have until now taken Russian Federation capsules to the space station - at a cost of up to $82m for a seat.
Since then, they have been in a race to see which company would fly first in what's become a sort of modern-day space race. The company also uses launchpads at the nearby Cape Canaveral Air Force Station (CCAFS) and Vandenberg Air Force Station in California. The unmanned test flight is scheduled for late 2018 or early 2019.
The SpaceX Dragon capsule, on current timelines, is set to make its maiden crewed flight in April.
Maintaining the International Space Station costs the federal government up to $4 billion a year, and NASA is working on plans to privatize it. And the moon has re-emerged as the pre-eminent space destination under the Trump administration.
But NASA's options may be limited by the global agreements that established the station in 1998.
NASA started the Commercial Crew Program in 2010, just before it retired the last space shuttle in July 2011. "We are committed to our partnership with Russian Federation on the International Space Station even after we have crew". Boeing's contract is for $4.2 billion; SpaceX's for $2.6 billion.