Washington (CNN) Congressional negotiators have rejected the House's plan to create a new "Space Corps" -- omitting the proposal for a new military branch under the umbrella of the Air Force from the final version of a nearly $700 billion bipartisan defense policy bill called the National Defense Authorization Act.

Despite support from House Armed Services Committee leaders -- including chairman Mac Thornberry -- the Space Corps proposal will not be included in the final NDAA for fiscal year 2018. Though the bill does contain language directing further long-term study of the issue, according to senior staff for both armed service committees, who briefed reporters on the contents of the bill Wednesday.

The proposal, which was included in the House's National Defense Authorization Act, would have set up a Space Corps in the mold of the Marine Corps, which is a separate military branch that's housed within the Navy.

The authors of the idea argued that a separate and dedicated force devoted to space is needed to keep the US ahead of adversaries like Russia and China in the still-emerging domain of space war, arguing the Air Force is primarily devoted to fighting in the air, rather than space.

Rep. Mike Rogers, the Strategic Forces Subcommittee chairman who proposed the idea, has argued that the Air Force was prioritizing its fighter jets over space, and a dedicated service was needed to stay ahead of China and Russia in what many see as the next frontier of warfare.

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