The House appeared ready on Thursday to push ahead with legislation ordering the Pentagon to create a new Space Corps service despite opposition by Defense Secretary Jim Mattis.

Rep. Mike Turner, R-Ohio, had hoped to win a floor vote on his amendment stripping the service from the National Defense Authorization Act but the House decided not to allow it, according to his staff.

The annual policy bill was heading toward a final floor vote and seemed almost certain to pass with its language creating the Space Corps under the Air Force to take the lead on space operations, which has become an increasingly important military frontier in recent years.

House Armed Services approved the measure last month and Rep. Mike Rogers, R-Ala., the lead sponsor, said it must be forced on the military to solve deep problems with the structure and management of space operations in the face of growing Russian and Chinese threats.

Mattis wrote an usual letter to Turner on Tuesday saying he is opposed to the creation of the new service because the Pentagon is still studying how to best manage space operations, and would prefer a more integrated approach that includes other service branches.

"I strongly urge Congress to reconsider the proposal of a separate service Space Corps," Mattis wrote.

The secretary and chief of staff of the Air Force have also strongly opposed the idea, saying it would create unneeded bureaucracy and hobble ongoing efforts to reorganize space operations.