F-35 to miss key interoperability target as initial mission software will lack ability to interface with Navy constellation

Lockheed Martin's F-35 Joint Strike Fighter will enter service without its planned satellite-communications capability, which has been delayed to a later software block. The issue is more timing than technical, and is the result of US Department of Defense plans to transition to a new satellite constellation.

The F-35 is planned to use the US Navy's Mobile User Objective System under development by Lockheed, with the first satellite scheduled for on-orbit handover in 2010. MUOS will replace the navy's UHF Follow-On constellation. Lockheed has just completed the critical design review on MUOS.

"[MUOS] did not have the interface documents ready, but we decided to stick with it and become interoperable with Block 4 or 5," says F-35 joint programme office air-vehicle director Capt Wade Knudsen. The F-35 is to become operational with Block 3 mission software, with development of Block 4 scheduled to begin in 2010, he says.

The timing mismatch is the cause of the F-35 missing one of its key performance parameters - interoperability - which encompasses "over 120 information exchange requirements", says Knudsen. The JSF programme is changing to a "net ready" KPP later this year, which will not include MUOS in Block 3.

The third and final JSF critical design review, for the US Navy's F-35C carrier variant, is planned for later this year, with the first aircraft scheduled to fly in May 2009 and initial operational capability now set for 2015 because of procurement cuts. Currently the F-35C is within its carrier recovery speed target of 145kt (268km/h) at 142.6kt and exceeding its range requirement at 1,190km (642nm), Knudsen says.

Source: Flight International