On the heels of statements of dissatisfaction by senior U.S. Air Force officials about the current delay of more than two years in producing the critical Mission Data Unit (MDU) of the DOD’s future GPS III satellite program, the USAF issued a Sources Sought ultimatum to GPS III contractor Lockheed Martin and its subcontractor Excelis. Such a declaration–essentially advising the contractor to improve performance and indicating that the agency is investigating other sources for the work–was a bombshell event for the aerospace community.

The MDU has been described as “the beating heart of the payload of each GPS III’s satellite” without which the $2.4 billion GPS III program could not operate, or even be launched. And for Excelis, which has successfully produced MDUs for several of the earlier GPS satellite series, the GPS III version has turned out to be a much more complex device. (As it happens, Excelis is the sole-source supplier of the FAA’s nationwide ADS-B ground station network, which it has delivered on time and within budget.)

But the USAF’s hard-nosed approach might not be unique to GPS III and could well reflect a growing DOD concern that, with few exceptions, industry’s cost and delivery promises on major programs have rarely been met. Indeed, the Sources Sought solicitation to industry–which notably excluded Lockheed Martin and Excelis–stated that a successful production-ready substitute MDU would compete with the incumbents (who already have firm contracts for the first eight shipsets) for the follow on, multimillion-dollar contract for the balance of 22 MDUs that otherwise would have been uncontested.

Boeing, Raytheon, General Dynamics and Northrop Grumman are expected to be strong competitors for that prize, but other challengers, such as Elon Musk’s Space X enterprise–already space qualified with an unmanned supply rocket to the International Space Station–and the UK’s Surrey Satellite Technology, a partner in Europe’s GPS-like Galileo satnav system, are also said to be keenly interested.

In full operation GPS III promises improved accuracy, higher-powered signals, greater jamming resistance and, with 30 satellites, more reliable performance in mountainous terrain and in city “canyons.” But a current DOD concern might be that GPS III’s currently unknown first launch date–unknown because of the MDU issue–and the follow-on launch timing might not keep up with progressive satellite failures in the current constellation. Typically, GPS satellite replacements follow in-orbit satellite failures, with an average failure rate of around one satellite per year. So far this year, however, four replacements were launched, suggesting that the number of in-orbit satellites is diminishing from a desirable 30 to a critical 24, below which coverage gaps could appear.