Lockheed Martin is working to extend the range of key U.S. missile interceptors designed to shoot down weapons launched by North Korea and Iran so that it could target super fast Russian and Chinese missiles of the future.

The U.S. defense giant has been quietly working on modifications to its Terminal High Altitude Area Defense interceptors, know as THAAD, that would allow the system to protect a wider areas, company officials revealed Wednesday. The upgrade would allow the interceptor to launch earlier giving it more time to take out an enemy missile.

“We see a growing interest from the [Missile Defense Agency] in this capability,” said Doug Graham, vice president of advanced programs for Lockheed’s strategic and missile defense systems. “We’re working them to try to define what specifically that system would look like.”

Unlike the current THAAD interceptor, which uses a single-stage rocket, the longer-range version would have two stages, similar to rockets that launch satellites into orbit. The first rocket would launch the interceptor to a high altitude in or above the Earth’s atmosphere while a second “kick stage” would propel the rocket toward the enemy missile.

“The first stage gets you out longer and higher against modern threats and the kick stage is responsible for narrowing the distance between the target and the interceptor so you could turn over to the kill vehicle,” Mike Trotsky, vice president of Lockheed’s air and missile defense business development, said.

According to Trotsky, Missile Defense Agency Director Adm. James Syring introduced the extended range concept for THAAD last year during a missile defense conference in Bucharest.

Missile Defense Agency spokesman Rick Lehner stressed the THAAD extended range is not an official “program of record” ordered up by the Pentagon. He said he could not confirm Syring’s comments in Bucharest because there is no transcript of the admiral’s speech and the conference was classified.

The Missile Defense Agency awarded Lockheed a $2 million contract for a “concept of operations supporting study for THAAD within an overall advanced technologies study program,” Lehner said in an email. These types of “concept studies take place on a regular basis for the entire Ballistic Missile Defense System to identify new technologies.”

“The study completed by Lockheed Martin is an industry concept and nothing more,” he said.

(Related: Your Pocket Guide to How U.S. Missile Defense Works)

A missile defense system works like this: A missile is launched. Ground and space sensors detect that launch and calculate the speed and path of the missile as it makes its way into space. A rocket-powered interceptor is then launched and put on a collision course with the missile, destroying it before it hits the target.

THAAD is designed to intercept an enemy missile as it re-enters the Earth’s atmosphere.

“By going to the [THAAD extended range] version, where you have a bigger booster and a kick stage, you can launch much earlier and you can attack that threat before he might try to do some evasive maneuvers,” Trotsky said.

Lockheed has invested more than $30 million over in recent years on engineering design and demonstration work for the extended range THAAD, Graham said. “It’s been a fairly high priority for us over the last five years.”

“I think what you’ll see from [the Missile Defense Agency] is an acceleration of that engineering work in the next few years because of the kinds of threats that we’re seeing being developed by our adversaries,” Trotsky said.

That threat includes hypersonic missiles traveling at more than five times the speed of sound in the high altitudes of the Earth’s atmosphere. Lockheed engineers have been “studying seriously” the hypersonic threat over the last 12 to 18 months, Trotsky said.

Russia has said it wants to develop a hypersonic missile before 2020 and China conducted its third test of a new hypersonic missile last month, according to reports.

“We’re definitely seeing adversaries developing and demonstrating capabilities that they believe can help to reduce the effectiveness of our systems,” Graham said. “We’re constantly having to stay ahead of the curve there.”

THAAD can already intercept missiles inside and out of Earth’s atmosphere, but an extended range version would improve that capability, Lockheed officials said.

“With an additional stage and an ability to loiter, THAAD [extended range] has been reported to have nine to 12 times existing THAAD coverage, and its increased velocity could potentially both counter hypersonic threats and have homeland missile defense applications, supplementing [Ground-Based Midcourse Defense],” said Thomas Karako, an analyst with the Center for Strategic and International Studies.

The U.S. Army has been using THAAD to defend Guam against possible North Korea medium and intermediate-range ballistic missiles. In January 2011, then-Defense Secretary Robert Gates said he believed North Korea was about five years away from fielding a long-range intercontinental ballistic missile.

The Pentagon has bought six THAAD batteries from Lockheed. Work will begin on a seventh this year and there have been talks about an eight and ninth for the Pentagon, Trotsky said. Four batteries are active and the fifth will be activated this year, Trotsky said.

And international interest in the THAAD system is growing. The United Arab Emirates is the first foreign buyer of the American-made system and will start receiving interceptors in 2016, Trotsky said. Qatar is also interested in the system and could move toward signing a contract this year.

Middle Eastern nations have been scooping up U.S.-made missile defense systems in recent years to defend against a potential missile attacks by Iran.

Just last month, Qatar signed a $2.4 billion deal with Raytheon for a new Patriot Air and Missile Defense System. In the Middle East, Israel, Kuwait, Saudi Arabia and UAE also operate the Patriot system.

CLARIFICATION: This story has been updated to reflect comments by the Missile Defense Agency that the extended-range THAAD project is a Lockheed concept, funded in part by the Defense Department, but not a new “program of record” weapon ordered by the Pentagon.