The United States’ National Aeronautics and Space Administration (Nasa) has dismissed its chief scientist and other officials as part of a federal workforce reduction order issued by President Donald Trump.

NASA is eliminating its chief scientist role and closing down an office that studies policy matters on space and technology, in a round of layoffs affecting 23 employees, the agency said on Monday.

NASA's acting administrator signed a memo that was sent to the employees, encouraging employees to “embrace the challenge” when the cuts go into effect.