U.S. space exploration inspired a generation of students and innovators, but NASA’s role has diminished, and the number of global space competitors is growing.

With President Donald J. Trump advocating for deep cuts to U.S. foreign aid, debate has renewed over the role of foreign assistance funds in boosting growth, promoting democracy, and saving lives.

By withdrawing from the Paris accord, the United States—the second-largest global emitter—could undercut collective efforts to reduce emissions, transition to renewable energy sources, and lock in fu…