Update (August 3, 2018): NASA announced nine astronauts (including a former one) to crew the first four spaceship missions by Boeing and SpaceX. Read about each person here.

NASA is about to name eight or more of the first astronauts ever to fly Boeing and SpaceX's brand-new spaceships.

The Commercial Crew Program, as it's called, is a spaceflight competition that NASA started about two years before retiring its space shuttles in July 2011. The goal: ensure NASA astronauts can access the International Space Station and end US reliance on Russia's increasingly expensive Soyuz spaceships to get there.

Boeing and SpaceX came out on top with their CST-100 Starliner and Crew Dragon space capsule designs, respectively. Boeing has earned about $4.8 billion in government contracts and awards for its work on the program since 2010, while SpaceX has earned about $3.1 billion. Each company's new ship could be test-launched (without any astronauts inside) by the end of the year.

If those uncrewed missions go well, Boeing and SpaceX will each follow with two crewed flights in 2019. After that, the companies will become eligible for many years' and billions of dollars' worth of future NASA missions.

Although NASA has not yet said which astronauts will be assigned to these historic first flights, four astronauts have already been working closely with Boeing and SpaceX in the testing and development of their capsules.

By the end of this week, however, at least eight names will be revealed.

"NASA will announce on Friday, Aug. 3 the astronauts assigned to crew the first flight tests and missions of the Boeing CST-100 Starliner and SpaceX Crew Dragon, and begin a new era in American spaceflight," the agency said.

Who might get to fly these historic private space missions?

More than 50 people are in NASA's astronaut corps, though 12 in the agency's 2017 astronaut class are still training. Anyone currently assigned to a space mission also won't be picked for the Boeing and SpaceX flights, NASA told Business Insider.

This leaves about 34 "active" and eligible astronauts. Here's what we know about the candidates and which ones are most likely to make history in the new space race.

Correction: This story has been updated to clarify that NASA could name more than eight of its own astronauts to crews, as well as some from Russia and Europe.