The U.S. Space Force is not concerned about relying on mercurial billionaires to provide space capabilities, according to top service leaders.

The service's ability to put large satellites in space rests primarily on the shoulders of Elon Musk, whose SpaceX test-flew a new heavy-lift rocket for the first time on Thursday, and Jeff Bezos, whose Blue Origin is slated to deliver engines to United Launch Alliance. 

A potential problem is illustrated by Musk's behavior toward Ukraine. In the months that followed Russia's invasion, SpaceX donated some 20,000 of its satellite internet terminals and millions of dollars' worth of service to the Ukrainian military. But in October, SpaceX wrote the Pentagon that it would cease its subsidy. Three months after that, Starlink officials said they had taken steps to hinder Ukraine's use of the terminals on the battlefield; Musk declared, in apparent contradiction of Starlink's work for the Pentagon, that the service was "never intended to be weaponized." Ukrainian and Pentagon officials have said they would seek alternatives to Starlink.

But despite Musk's hot-and-cold attitude, the U.S. Space Force is not concerned about heavily relying on these companies, Chief of Space Operations Gen. Chance Saltzman said Wednesday at the Space Symposium. 

Air Force Secretary Frank Kendall echoed Saltzman's comments, saying, "The Pentagon relies on executable and enforceable contracts with industry."