The advanced solid rocket motor has emerged as a key area of concern as the US Army weighs two teams vying for the joint air-to-ground missile (JAGM) contract.
Much of the spotlight in the competition for JAGM between Lockheed Martin and a Raytheon/Boeing team has focused on the tri-mode seeker.
Both companies last month completed a technology demonstration that included three test flights to check each mode of the advanced sensor. Raytheon/Boeing scored three direct hits, but Lockheed missed the target twice.
But army officials now appear concerned about the technical maturity of the advanced motor that must power the missile at both high and low altitudes and across a variety of vibration and pressure levels.
"That was always the physics PhD project for JAGM," says Mike Riley, Raytheon business development lead for JAGM.
A new draft of a tentative request for proposals released on 15 October inserts a new requirement. The army will require the team that ultimately wins the contract to submit a risk-reduction plan for the solid rocket motor.
The new requirement is unusual because both companies have focused on developing a single solid rocket motor that can operate at all extremes of the JAGM flight envelope.
Because the weapon must be fired from fast jets and helicopters, the propellant must survive in freezing temperatures at high altitudes. In addition to absorbing the Boeing F/A-18's g-loads, the propellant also cannot leave a telltale trail of visible smoke.
Lockheed teamed with Roxel/Aerojet to develop a propellant and motor, while Raytheon/Boeing is partnered with ATK. Lockheed demonstrated its version during the technology demonstration phase. The Raytheon/Boeing team used a different motor during the three flight tests, but has recently completed a flight test using the ATK system.
Both teams are now waiting for the army to release a final copy of the request for proposals to launch the final phase of the competitive process.