The aerospace company, which is the primary contractor for the rocket's large core stage, issued the notifications as part of the Worker Adjustment and Retraining Notification (or WARN) Act, which requires US employers with 100 or more full-time employees to provide a 60-day notice in advance of mass layoffs or plant closings.

Boeing Co. expects to lay off hundreds of workers on its SLS moon rocket program, fueling speculation that NASA’s marquee space exploration initiative is poised for a shake-up under a second Donald Trump administration.