Why is the U.S. government building a space rocket? In particular, why is it building a space rocket that has cost nearly $20 billion and counting, is years behind schedule, relies on outdated technology, and suffers by comparison to private-sector alternatives?

The Space Launch System is the two-stage, heavy-lift rocket that aims to bring American astronauts back to the lunar surface and then — sometime in the distant, hazy, not-too-specific future — to Mars.

Initiated in 2011, it was built using technology and components that dated to the early space-shuttle era.

A report last year from NASA’s inspector general warned of “rising costs and delays,” “shortcomings in quality control,” “challenges with program management,” “technical issues,” “development issues,” “infrastructure issues,” “performance issues” and more. A watchdog report in December found “uncertain plans, unproven cost assumptions and limited oversight.”

In January, a critical test fire of the rocket’s engines was aborted when computers detected an anomaly. Although the issue turned out to be minor, the failed test created a major problem: The core stage of the rocket, which is supposed to eventually launch a spacecraft to the moon, can only be loaded with super-cooled fuel nine times in its usable life. With three of those chances now expended in dress rehearsals, NASA must consider whether to forgo another test to preserve some margin for error for the actual launch (whenever that may be).

Plus, the SLS is being assembled just as the private rocketry business has started to boom. Elon Musk’s SpaceX has created rockets that are not only dependable but reusable, drastically reducing the cost of spaceflight. It has also disrupted an unconscionable contractor monopoly on national security launches, spurring competitors to invest in reusable heavy-lift rockets of their own, including Blue Origin’s New Glenn launch vehicle.

A few years down the road, such competition is likely to result in more choices, lower costs and more innovation. Musk estimates that, in due course, each launch of SpaceX’s reusable super-heavy rocket will cost about $2 million, or about 0.1% of the cost of a comparable flight of the single-use SLS. Even if that prediction turns out to be highly optimistic, there’s simply no contest.

One could make the debatable case that returning to the moon will be a useful (albeit expensive) precursor to deeper-space missions in the years to come. But no such mission is realistically on the horizon. And relying on a hugely expensive single-use rocket to establish “a sustainable human lunar presence,” as NASA intends, when cheap and reusable commercial options will soon be available, makes no sense.

No doubt, the era of government spacefaring had its glories. But space is now a $424 billion business, with U.S. companies at its forefront. The new administration should embrace this revolution, and bring the power of private enterprise to bear in crossing the next cosmic frontier.