NASA estimates it will save as much as $30 billion by using third-party companies like Boeing and SpaceX to build spacecraft to shuttle astronauts to and from the International Space Station.

In a new report released Wednesday, May 13, the space agency says the Commercial Crew program, which has been criticized for substantial delays, will result in taxpayer savings over the life of the program that exceed the entire 2020 NASA budget.

“While not done yet, [Commercial Crew] is poised to save the Agency approximately $20B-$30B, and provide two, independent crew transportation systems,” NASA said.

NASA’s 2020 budget currently stands at $21 billion.

The Commercial Crew program has seen two contracts awarded to third-party spacecraft companies.

Boeing has taken in roughly $4.8 billion over the past 10 years, while SpaceX has earned $3.1 billion. NASA’s estimate of the savings from those contracts reflects a comparison to previously estimated costs to build its own ships, a program that was known as Constellation.

The first Commercial Crew flight is set to occur at 1:33 p.m. PT on Wednesday May 27. NASA astronauts Robert Behnken and Douglas Hurley entered quarantine Wednesday to prepare for the flight. They’ll travel to the ISS on a SpaceX Crew Dragon spacecraft.

They will be the first American astronauts to fly to the station on a spacecraft launched from American soil since the last Space Shuttle flight in 2011.

The quarantine has nothing to do with the recent COVID-19 coronavirus pandemic. Pre-flight two-week quarantines have been standard operating procedure for NASA for decades.