The president could tighten federal oversight of the tech titan’s businesses, even if heavy reliance by the Pentagon and NASA on them makes terminating Mr. Musk’s contracts less feasible.

© Joe Skipper/Reuters

President Trump’s decision to pull a close associate of Elon Musk’s out of the running to lead NASA helped doom an extraordinary partnership.

© Haiyun Jiang for The New York Times

Research breakthroughs are often sagas of passion, curiosity and sacrifice. If Trump’s proposed budget cuts for 2026 are enacted, many such journeys may never get started.

© Caitlin O'Hara for The New York Times