Lockheed Martin is claiming a technical breakthrough with a solid propellant rocket motor propulsion system in the competition for the prized joint air-to-ground missile (JAGM) contract.

Lockheed's propulsion supplier Aerojet, in partnership with UK-based Roxel, has demonstrated a propulsion system designed to address a uniquely challenging requirement for the JAGM programme, team officials say.

To launch from both helicopters and fast-moving jets at high-altitude, the JAGM rocket motor must be capable of firing at maximum thrust despite soaking in temperatures as low as -53.9°C (-65°F). For long-range shots, the rocket motor then must "turn down" thrust from maximum to "sustain" levels.

The Lockheed team's competitor - a Raytheon/Boeing combination - also claims to have addressed this requirement, relying on Boeing's contributions to the MBDA Brimstone missile used by the UK Royal Air Force.

Lockheed's approach, however, depends on propellant technology offered by Roxel.

"They bring a set of propellant characteristics that offer very low sensitivity to temperatures across an extremely wide operating range," says John Myers, vice-president of tactical programmes at Aerojet.

The Roxel propellant means Lockheed's JAGM design is compatible with the existing rail launchers for both its AGM-114 Hellfire and Raytheon's AGM-65 Maverick air-to-surface missile, reducing lifecycle logistics costs. At the same time, the new weapon will provide twice the range of a Hellfire launched by a helicopter and match the range of a jet-fired Maverick.

"You've got the toughest requirement of both types of platforms," Myers says. The programme also includes introducing a tri-mode seeker, allowing the JAGM to strike moving targets in all weather conditions.

Both teams are competing to replace thousands of Hellfires and Mavericks. The US Army and US Navy are conducting a technology development phase that will be complete by the end of the year.

One contractor should be selected to enter an engineering and manufacturing development phase in early fiscal year 2011, which starts on 1 October.

Source: Flight International