There is a saying in Washington defense circles: The threat always gets a vote. It means that a valid strategic threat can influence decision-makers to derail or accelerate a weapons program. In the case of the most expensive aircraft program in history, the Joint Strike Fighter (JSF), seniorPentagon officials have begun considering what might happen if the still-developmental F-35 were compromised by the proliferation of ever-more-capable air defenses.
It is not news that the single-engine F-35, developed by Lockheed Martin, is being introduced into service about eight years late. The Pentagon has managed to stem the program’s financial hemorr–haging since a massive restructuring in 2011. JSF, originally estimated to cost $200 billion to develop and buy, is now expected to cost $400 billion, and production for the F-35 is expected to stretch well into the 2030s.
But funding aside, the precious years of delay have not just forced its respective customers to maintain older fleets longer than planned. During this time, the strategic threat has evolved. This is increasingly part of the discussion, as the Obama administration prepares to hand off its Pentagon plans to a successor in two years.
THE THREAT
There is a “growing concern” among senior officials in the Office of the Secretary of Defense about the proliferation of advanced air defense radars and anti-aircraft weapons, says an industry official familiar with these discussions. “We took a long time on this. The threat is taking some turns on us.” Senior officials are loath to cause alarm and jeopardize the coalition behind the F-35 and are thus tight-lipped about it. 
The situation is not at a crisis point yet, one industry source says. Obsolescence is inevitable for any weapon system; the discussion now is about when that could happen for the F-35 and how to address it if it is sooner than hoped. “We are starting to see the emergence of some stressing capabilities to our conventional forces,” Al Shaffer, acting assistant secretary of defense for research and engineering, told Aviation Week during an interview last March. He was referring to the emergence of radars operating in very-high-frequency bands that can detect stealthy aircraft at long range. The concern is that these VHF radars could eventually pass targeting data to fire control elements for air defense systems.
Advocates for the Boeing F/A-18E/F used this argument—that stealth is being compromised—last year in a campaign to steer the Navy away from the F-35C optimized for carrier operations and toward the Boeing Super Hornet. The discussion raised awareness of the F-35’s vulnerabilities. But policymakers are less inclined to invest in more F/A-18E/Fs, developed in the 1990s, and toward a next-generation capability. Perhaps this ultimately serves Boeing’s interests, as the aerospace monolith would likely vie for a part in an F-35 successor program, along with Northrop Grumman and Lockheed. 
Russian “anti-stealth” radar systems on display at the Moscow air show in 2013 justified concerns about stealth, and the Russians are thought to have made advances in integrating their air defenses. Also, a Chinese manufacturer last year showcased a so-called counter-stealth VHF active, electronically scanned array radar at the Zhuhai air show.  
“Stealth is an interesting discussion, because people tend to identify a piece of it and think someone will compromise that piece and [conclude] that therefore stealth is no longer valuable,” said Air Force Chief of Staff Gen. Mark Welsh during a Jan. 15 press conference at the Pentagon. “The reality is, stealth is a combination of things. It is not just [being] low observable. It’s also speed, low observability, different ways of collecting data, different ways of transmitting and protecting transmissions. It is a way of breaking kill chains.”
The reality of an evolving threat is influencing plans for the next-generation Long-Range Strike Bomber, which is more likely to take advantage of broadband stealth technologies. Likewise, planners are considering broadband stealthiness for sixth-generation fighters—the F/A-XX for the Navy and F-X for the Air Force.
THE STUDY
These senior officials are in the preliminary stages of examining options should stealth—one of the F-35’s key attributes—be compromised by new technology. The idea is to be able to hand off to the next presidential administration both a healthy F-35 program—no small feat, after its years of pitfalls and overruns—and other options should the next president find the aircraft’s technology outdated, the industry source says. The hope is the F-35’s technology will be viable for decades to come.
The studies are preliminary and academic at this point, and they do not indicate the Pentagon is backing away from the F-35; its support has been unwavering since the 2011 restructuring. The Pentagon is now planning for a substantial ramp-up in production for the fighter over the next five years.  
Even as the fifth-generation F-35 (bottom) is ushered into the fleet alongside fourth-generation predecessors, such as the F-16 (top), defense planners are eying options in case F-35 stealth technology is compromised. Credit: USAF Senior Airman Cody Griffith
At last year’s Farnborough Air Show, Pentagon procurement chief Frank Kendall proclaimed there is no need to buy more Super Hornets. Last month, Welsh doubled down on the USAF’s plan to declare initial operational capability for the F-35 by December 2016, despite a possible shortage of trained maintainers. “While we may have a new radar developed that allows an acquisition radar to see an airplane, that doesn’t mean [it] can pass the track off to a radar that will then guide a weapon to be able to destroy the airplane. As long as we break the kill chain sometime between when you arrive in the battlespace and when the enemy weapon approaches your airplane, you’re successful at using stealth,” he said.
A follow-on to the F-35 could cannibalize some of these technologies and lessons for a new program but also incorporate more modern techniques and equipment, the industry official suggests. Options might include the use of cyberoffenses during campaign planning to cripple radars that could jeopardize stealthy allied aircraft. Improved thermal management systems could help guard against infrared threats, while advanced electronic countermeasures could protect a future jet at war.
These options are all part of a “what-if” discussion that is part of prudent planning, the official says.
The main strength of the F-35—global backing among Washington’s allies—could become a weakness. Should the aircraft be compromised, perhaps by counterstealth technologies or a cyber hack, its impact would be equally global.
A cyber intrusion into the program, in which terabytes of data were allegedly surveilled or stolen underscored this reality. Allies nervously awaited feedback on whether the so-called crown jewels of the F-35 were compromised in an alleged Chinese cyber intrusion into the program. Classified documents released by the notorious leaker Edward Snowden indicate some data related to the F-35 engine, thermal management system and radar were accessed by the hackers. Program spokesman Joe Dellavedova maintains that no damage was done to the program. Put simply, the F-35 is still a huge target for adversaries.
The JSF consortium includes nine partner nations—the United States, Great Britain, Italy, The Netherlands, Denmark, Turkey, Australia, Norway and Canada. Israel, Japan and South Korea have also selected the F-35.
The question being broached is how the Pentagon could still reap benefits from the $55 billion invested in the development if the aircraft is compromised. Billions of dollars have been invested in the F-35’s stealthy qualities —including radar-absorbing coatings and thermal management systems as well as an unprecedented fusion in its threat warning systems and avionics, which are designed to allow pilots to deftly navigate the battlespace. 
Likewise, billions of dollars have gone into developing the largest fighter engine ever—the Pratt & Whitney F135, which provides 43,000 lb. of thrust and the advanced Northrop Grumman AN/APG-81 active, electronically scanned array radar. Also unique to the F-35 is its use of a new waveform, the Multifunction Datalink, which allows covert transmission of data among the fighters during missions. Each of these elements could be cannibalized into a successor program, should that become necessary, the industry source says.
The review is described as informal, but is likely to continue until the change of administration in 2017. 
A version of this article appears in the February 2-15, 2015 issue of Aviation Week & Space Technology.