WASHINGTON — As the U.S. Air Force grapples with a growing mismatch between the military’s need for protected satellite communications capacity and its ability to provide it, the service is exploring a range of potentially money-saving alternatives from new transmission waveforms to hosted payload arrangements.

What is becoming clear in the process is that in the context of satellite communications, the term ‘‘protected” can mean different things to different people.

Industry officials agree that the current Advanced Extremely High Frequency constellation is the gold standard of protection for military satellite communications. The satellites, built by Lockheed Martin Space Systems of Sunnyvale, California, with Northrop Grumman Aerospace Systems of Redondo Beach, California, supplying the payloads, are designed to provide assured and highly secure communications links under all conditions, including a nuclear war.

The Air Force has six AEHF satellites, which today cost more than $1 billion each, under contract, with three of those on orbit. The service does not have any money in its latest five-year budget projections for additional AEHF satellites, and while several industry officials believe the service ultimately will end up ordering more, Air Force officials have hinted that the funding pause is an opportunity to explore alternatives.

One much-discussed option is flying the strategic and tactical AEHF payloads on separate satellites. This option appears attractive because the demand growth for secure communications is driven primarily by tactical users, and these payloads do not need the same protection against nuclear radiation effects such as electromagnetic pulse that the strategic payloads require.

But on the tactical side, what constitutes protection might range from being resistant to incidental or unintentional interference to deliberate jamming by a well-equipped and determined adversary.

“There are shades of gray here,” said Chuck Cynamon, vice president of U.S. government business development for Space Systems/Loral (SSL) of Palo Alto, California. “It’s not, ‘You’re protected or you’re not.’”

The Air Force has funded a series of tests in an effort to evaluate protected satellite communications alternatives and demonstrate the potential for dramatically lowering the cost of delivering highly secure services via both commercial and military satellites.

In early March, for example, engineers conducted tests of anti-jam modems and waveform technology developed by L-3 Communications Systems-West on a Ku-band satellite simulator and over an SSL-built commercial telecom satellite. L-3  officials said they demonstrated voice, video and IP data transmission via the Air Force’s new Protected Tactical Waveform. Air Force officials observed the test, the companies said in an April 7 news release.

In another test, in December 2013, Boeing Space & Intelligence Systems of El Segundo, California, transmitted protected signals via the Air Force’s Wideband Global Satcom X- and Ka-band communications satellites, according to a press release from the company.

Mark Daniels, vice president of engineering and operations at Intelsat General, said industry is eager to show the Air Force that commercial satellites can help meet the service’s protected communications needs through technologies such as steerable satellite spot beams and anti-jam modems. Intelsat General of Bethesda, Maryland, is the government services arm of Intelsat, the world’s largest commercial satellite operator by revenue.

Daniels also said Intelsat could fly an AEHF payload on one of its satellites under the Air Force’s Hosted Payload Solutions contracting vehicle. The Air Force’s space contracting arm, Space and Missile Systems Center in Los Angeles, plans to award multiple indefinite-delivery, indefinite-quantity contracts this summer to a mix of satellite operators and space hardware manufacturers who would then be qualified to provide hosted payload services to the military.

According to Northrop Grumman, what many refer to as protection in the tactical communications realm falls well short of the ability to thwart a determined and technically advanced adversary. That capability, which includes anti-jamming as well as low probably of detection and interception, can be a big cost driver on satellite programs, briefing charts produced by the company suggest.

But Tim Frei, vice president of communication systems for Northrop Grumman Aerospace Systems, said the company has developed options that would provide AEHF-level protection with significantly increased resilience and tactical capability at a lower cost than the current AEHF spacecraft.

Frei said Northrop Grumman sees a demand for greater levels of protection that “are at least on par with the capabilities of today’s AEHF tactical services.”

Protected communications “need to be resilient to adversaries’ determined attempts to deny service through electronic, physical (ground or space), or cyber attacks,” Frei said in an April 25 email. “Wideband Global SatCom (WGS) and commercial systems are simply not designed with the capabilities required for operating in those environments or for countering those kinds of threats.”

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.