ORLANDO, Fla.–Lockheed Martin [LMT] is designing a very long-range cruise missile that can reach deep into enemy territory with a large warhead to destroy hardened underground facilities and cave and bunker complexes, according to company officials.

Known as the Cruise Missile Extended Range (XR), the company-funded concept entails a stealthy, 5,000 pound-class weapon that can fly out to 1,000 nautical miles to deliver a lethal payload up to 2,000 pounds precisely on target, said Ed Whalen, director of Strike Weapons Business Development for Lockheed Martin Missiles and Fire Control.

“Cruise Missile Extended Range is something we are looking at internally based on what the warfighter has told us,” Whalen told sister publication Defense Daily recently during an interview at the company’s facility here. “If you look at the problem out there, the adversary is putting their targets deeper range-wise and deeper penetration- wise.”

Accordingly, the company has been refining the design of a GPS-guidance-aided cruise missile that could be launched by aircraft that are safely beyond the kill zones of sophisticated air defenses, or fired from ships outside of the reach of anti-access threats, yet still have the range to hit difficult-to-access sites and strike them with a powerful punch. Such targets include production or storage facilities for weapons of mass destruction, command-and-control centers, air defense nodes, and ballistic missile sites, he said.

The missile could also be used to strike time-critical moving objects, he said.

“We have cruise missiles that go 1,000 miles,” said Whalen of existing weapons in the U.S. inventory. “But we want something more in the 5,000 pound-class that can go that range and carry a lot more payload than what is out there right now in the legacy systems.”

For example, the Navy’s Tomahawk Block III and Block IV cruise missiles, which are built by Raytheon [RTN], have a range up to 1,000 nautical miles, thus equal to the XR concept, but carry payloads up to 1,000 pounds, or about half of the XR’s capacity, according to Raytheon’s Tomahawk fact sheet.

Further, while the Air Force’s Boeing [BA]-built AGM-86 Conventional Air Launched Cruise Missile (CALCM) can carry a comparable payload in terms of weight, the missile’s range is, at 600 nautical miles, comparatively less than that of the XR, according to the Air Force’s CALCM fact sheet. Additionally, CALCM is not considered as survivable as newer, stealthy strike weapons such as Lockheed Martin’s AGM-158 Joint Air-to-Surface Standoff Missile (JASSM), which is now in service with the Air Force.

JASSM, which the Royal Australian Air Force is also purchasing, has a range of 250 nautical miles and carries a 1,000 pound-class warhead. An extended-range variant in development for the U.S. Air Force called JASSM ER can fly more than 500 nautical miles.

“A regular, baseline JASSM is a truck [for delivering a warhead],” said Whalen. Cruise Missile XR, he said, “is a Mack truck, a lot bigger truck.”

Whalen said Cruise Missile XR leverages technologies used in the air-launched JASSM, such as the latter’s stealthy materials and manufacturing processes. Its notional features include precision delivery accuracy without the need for a seeker, potentially via an external means of bolstering the accuracy of the GPS signal. It also has a two-way datalink for line-of-sight communications and connecting to battlefield information-sharing networks that are beyond line of sight, and a modular front end to accommodate various warheads.

Whalen said the warhead, which would range between 1,500 pounds and 2,000 pounds, could include a dual-mode system like on the JASSM that allows both for penetration or blast fragmentation effects, or a front-end dispenser for delivering precision-guided submunitions.

“You could have a cruise missile, even one this big, dispense submunitions as you went through the battlefield, and then it would seal up and keep its stealth characteristics,” he said.

Lockheed Martin is already developing such submunitions for the Air Force under a low-cost cruise missile initiative.

The Cruise Missile XR design would also minimize the potential for collateral damage and, depending on the configuration, be able to pass battle damage information back to command centers, said Whalen.

Whalen said Lockheed Martin continues its internally financed design work on Cruise Missile XR in the hopes that the Air Force or Navy will decide to pursue the weapon at some point and fund its maturation. The company has already conducted wind tunnel testing of several variations of the missile, he said.

“The Air Force is going toward next-generation long-range strike with a bomber,” said Whalen of the service’s intent to field a new strike capability by 2018. “What a missile like this would do is give a capability until that is fielded. A legacy airplane with a very long range cruise missile could standoff and be effective, versus having to drive all the way in across the target and put that crew at risk.”

Notionally, Air Force F-15E multirole fighter aircraft could carry up to four Cruise Missile XRs and Air Force bomber aircraft like the B-52H up to 12 of them, according to Whalen. Variants of the missile could also be operated from vertical launch tubes on Navy surface combatants. Conventionally armed missile submarines could carry up to 88 of them, or four per launch tube on the sub, he said. Other delivery modes include cargo aircraft that have been converted to roles as “arsenal planes,” he said.

For missions involving less distance, the missile’s inherent range could be translated into extended loiter time, Whalen said. Cruise Missile XRs could be launched and placed in a holding pattern in friendly airspace in some scenarios until the enemy forces emerge from their protected areas, he said.

In 2004, Lockheed Martin divulged work on an internal project called JASSM XR that envisioned a variant of the JASSM with attributes similar to what the company is now discussing under Cruise Missile XR. However, company officials caution that the two concepts are not synonymous.

Cruise Missile XR, they said, is not tied to any delivery mode such as JASSM XR, which was originally seen as a weapon for carriage exclusively on Air Force bomber aircraft.