Weapons in space. Fighter jets powered by artificial intelligence.

As the Biden administration comes to a close, one of its legacies will be kicking off the transformation of the nearly 80-year-old U.S. Air Force under the orchestration of its secretary, Frank Kendall.

When he leaves office in January — after more than five decades at the Defense Department and as a military contractor, including nearly four years as Air Force secretary — Mr. Kendall, 75, will have set the stage for a transition that is not only changing how the Air Force is organized but how global wars will be fought.

One of the biggest elements of this shift is the move by the United States to prepare for potential space conflict with Russia, China or some other nation.

In a way, space has been a military zone since the Germans first reached it in 1944 with their V2 rockets that left the earth’s atmosphere before they rained down on London, causing hundreds of deaths. Now, at Mr. Kendall’s direction, the United States is preparing to take that concept to a new level by deploying space-based weapons that can disable or disrupt the growing fleet of Chinese or Russian military satellites.

To Mr. Kendall, there is no other choice for the Air Force.

“If there were one thing I could accomplish as secretary, it would be to give the enterprise — the institution — a sense of urgency about responding to the threat and being more prepared,” he said during an hourlong interview at the Pentagon this month with The New York Times. “Conflict can happen. It’s not inevitable. It may not even be likely. But it can happen at any time. And we need to be ready.”

Perhaps of equal significance is the Air Force’s shift under Mr. Kendall to rapidly acquire a new type of fighter jet: a missile-carrying robot that in some cases could make kill decisions without human approval of each individual strike.