As Congress begins its review of the president's fiscal 2016 budget, I recently witnessed a welcome sign of interest from congressional staffers who attended a standing room-only, roundtable discussion on missile defense. The questions and discussion were insightful, and brought clarity to the Missile Defense Agency's (MDA's) sound strategy to defend against a rapidly evolving missile threat.

During recent congressional testimony, both the Army chief of staff and the commander of US Northern Command cited ballistic missile defense as a key area for investment. Testimony by the director of the Defense Intelligence Agency 's director's testimony to the House Armed Services Committee clearly states that our adversaries and competitors continue to develop air and missile systems to challenge the United States and its partners. The president's budget reflects these points and fully funds MDA's request for approximately $8.13 billion, dollars, after years of underfunding.

In 2014, North Korea launched more than 100 ballistic missiles and they continue launching them, as well as testing new cruise missiles. They appear to be developing a ballistic missile submarine and state that their KN08 road mobile missile launcher is operational. Meanwhile, Russia's and China's development of hypersonic Hyper-glide vehicles seems to be moving forward too.

Iran recently declared itself the fourth greatest missile power in the world; put a satellite into space; unveiled a new , long-range cruise missile that can range across Europe; and says they are about to launch a second satellite.

Iran's space program is making headway, so one has to wonder if the Director for National Intelligence's 2014 Statement for the Record to the Senate's Select Intelligence Committee will come to fruition soon: "...Iran's progress on space launch vehicles…provides Tehran with the means and motivation to develop longer range missiles, including an ICBM.'

The threat is real and is becoming more challenging so we must sustain our investments in missile defense to deter and defeat it. MDA's budget request applies $1.8 billion to the Ground-based Midcourse Defense (GMD) system, the US homeland's sole defense against defensive capability from a long-range missile attack. That level of funding is critical to executing MDA's well-thought-out set of GMD system priorities: increasing the interceptor inventory to 44 by 2017, improving sensor performance and reliability, developing and testing advanced kill vehicles, and developing a long-range discrimination radar.

Last June's successful GMD flight test validated a modification and the lethality of the CE-II kill vehicle, as well as MDA's system engineering model. The next step to further improvements to the kill vehicle should be a prudent, evolutionary path to a redesigned kill vehicle. MDA's intent to pursue an open architecture approach in the redesign will simplify the integration of future enhancements and provides a low-risk approach for improvements. This focus should be a priority effort and not one clouded by competing PowerPoint-based better ideas.

The concept of developing a common kill vehicle or a multiple-object kill vehicle is technically high-risk and a significant engineering challenge. Moving forward with a near-term redesign of the proven, but first-generation kill vehicle is the low-risk, cost effective, and operationally sound approach. The threat and fiscal realities demand this and neither MDA, nor the nation, can afford to have funding diverted to mythically revolutionary approaches at this time.

The other kill vehicle concepts have merit, but if pursued in lieu of the redesigned kill vehicle, they deny the warfighter necessary near-term capabilities for virtual promises that rarely deliver on schedule or in budget. This nation cannot afford to gap our missile defense capability.

With this clear focus on the redesigned kill vehicle, MDA will then be able to tackle its their next priority: the development of a long-range discrimination radar by 2020. This new radar is a key improvement to the ballistic missile defense system's architecture, adding persistence and enhancements. to the systems overall performance.

GMD's battlespace is the most challenging of all the missile defense systems in the field today. Its current sensors tell us, "a launch has occurred, the object of interest is on this flight-path, it is approximately here." That approximation is usually a volume of space and inside that volume can be all sorts of other objects besides the threat missile's warhead — the true object of interest.

A discrimination radar, with its precision, will determine which object is the warhead and generate precise information to improve the probability of intercept. This is another, well-thought-out and low-risk, technically achievable enhancement; it to the architecture; that requires full support and funding.

In the realm of air and missile defense, our adversaries and competitors never really take a "development holiday" or accept a "peace dividend." They always seem to be advancing their capabilities. It is critical to our national defense, as well as that of our allies and partners, that we continue to advance our capabilities to ensure we outpace and retain over-match of the threat.

The MDA's Missile Defense Agency's wise approach to one of the most complex and technically difficult defense challenges in the space age requires full support. MDA has a well-balanced program to enhance defense of the homeland and provide for the defense of deployed forces and our partners. The Armed Services and Appropriations committees needs to fund both the redesigned kill vehicle and the long-range discrimination radar, and fully fund MDA's FY16 request.

The safety of American citizens from coast to coast and around the globe depends on it.

Retired US Army Maj. Gen. Francis Mahon is an independent defense consultant. He is a former head of the Army's Air and Missile Defense Command and former director of test at the Missile Defense Agency. former air defense commander and a former director of strategy, policy & plans at NORAD-US Northern Command.and am not in the employment of any of the major defense contractors