A Senate defense panel wants to create a separate fund to underwrite the nation's new nuclear-armed submarine fleet, a step the House also supports.

The Senate Armed Services Committee's mark-up of its annual defense authorization legislation calls for the establishment of a "National Sea-based Deterrence Fund" to finance the construction of new submarines to replace today's Ohio-class ballistic missile vessels, according to a detailed panel summary of the bill released on Friday.

The Democratic-controlled committee approved the legislation on Thursday by a near-unanimous vote. On the same day, the Republican-controlled House passed its own version of the fiscal 2015 policy-setting bill that also included language ordering the creation of a special fund to pay for the new "SSBN(X)" fleet.

The House legislation authorizes the Defense Department to transfer up to $3.5 billion to the Ohio-class replacement account from "unobligated funds" authorized for fiscal years 2014 to 2016. Meanwhile, the Senate bill would authorize an initial $100 million to get the fund going.

Congressional support for creating a separate fund for the Ohio-class successor stems from concerns that the submarine-building effort could eat up too much of the Navy's overall shipbuilding budget. The project currently is in the design and development stage, with construction of the planned 12 new strategic submarines expected to start in fiscal 2021. The vessels are to be armed initially with the Navy's nuclear-tipped Trident D-5 ballistic missile.

The latest moves in the two chambers come on the heels of skepticism by a key supporter of the separate-funding idea for new submarines, Representative Randy Forbes (R-Va.), who said recently that the approach would be unlikely to gain full congressional approval this year.

Meanwhile, the Senate Armed Services Committee also approved boosting funds for the Ground-based Midcourse Defense system to the tune of $30 million above the Obama administration's request. The additional money is to be used "for improvements in reliability and maintenance" of the antimissile program, according to the summary report.

The GMD program – comprising 30 Ground Based Interceptors deployed in California and Alaska, plus a network of sensors – is the country's principal line of defense against a limited long-range ballistic missile attack. However, it has had a number of recent testing problems that have been so troubling that the Pentagon's Missile Defense Agency in March announced it would redesign the interceptor's front-end kill vehicle.

This comes as the military is planning to procure another 14 interceptors for fielding in Alaska, in response to a possible missile threat posed by North Korea.

The draft Senate legislation would order the Pentagon to "develop a robust acquisition plan" for the redesign of the kill vehicle, which uses kinetic energy to destroy incoming ballistic missiles, in order "to provide confidence that it will work in an operationally effective manner," the summary states.

The bill also would mandate that the Department adhere to the "fly-before-you-buy" approach for affirming through testing the soundness of ballistic missile defense technologies before they are purchased or deployed. The Missile Defense Agency has come under repeated criticism from independent experts and by Congress' internal watchdog for not sufficiently following this acquisition strategy in its development and expansion of the Ground-based Midcourse Defense program.