Key point: Israel is well-practiced at improving on American military technology.

For fifty years, the United States has provided top-of-the-line fighter aircraft to help defend Israel from attack. Israel’s fielding of the F-35 Joint Strike Fighter, known locally as Adir, continues that tradition even as the country puts its own technological touch on the fifth-generation fighter. Unlike other F-35 customers, Israel is modifying its fighters from the outset to address unique security challenges and the country’s technological capabilities.

The United States began sending first-line fighters to Israel in the late 1960s, when the F-4E Phantom II joined the Israeli Air Force. The F-4s were followed by the F-15A Eagle air superiority fighter in 1976, and by the F-16A Fighting Falcon multirole fighter in 1980. These fighters were eventually followed by the F-15C, F-15I strike fighter, and F-16C and F-16I fighters. With the exception of the F-22 Raptor, the Israeli Air Force’s fighter fleet is as well equipped as the U.S. Air Force’s.

Israel first applied to buy the F-35 in September 2008, when it requested to purchase twenty-five jets with an option for another fifty. The F-35s would fill a void created by retiring early-model F-16s. According to Defense Industry Daily, the Israelis were quoted a sticker-shock-inducing $200 million per jet. While this number came down considerably within a year to a more concerning $100 million plus, it was clear the F-35 would be a very expensive purchase for the tiny Middle Eastern country. By October 2014, Israel agreed to double its F-35 fleet to fifty aircraft.

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Unlike many of the Lockheed Martin’s F-35 customers, Israel pushed for and received permission to integrate a number of local technologies into their aircraft, which was locally named the F-35I, or Adir (“Mighty”). Israel made the case that it lived in a state of near-constant conflict and this required the country’s F-35 fleet to not only stand apart logistically but technologically.

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One key technology is the integration of an Israeli-developed command, control, communications, computer and intelligence (C4I) system into the Adir. The stand-alone system draws sensor data from the aircraft but otherwise does not interact with the F-35’s computer system. From there, the C4I system pushes out the data to other Israeli military assets, particularly nearby fighters, via locally made data links to help detect, prioritize and attack enemy targets.

The C4I technology is particularly necessary in light of the immense rocket threat to Israel—Hezbollah alone is thought to have up to 150,000 tactical rockets it can shower on the small country. In any future war the number of rocket-launch locations could be overwhelming—that is, unless Israel can rapidly draw in launch-location data, process it and quickly churn out a prioritized target list for the Israeli Air Force to hunt down.

The F-35I will also carry Israeli-designed missiles. The jet will carry defense contractor Rafael’s SPICE 1000 precision-guided bomb instead of the GPS-guided JDAM bomb. SPICE (“Smart Precise Impact Cost Effective”) 1000 is an add-on package that bolts both satellite and an electro-optical guidance systems on an unguided Mk. 83 thousand-pound bomb. This allows SPICE 1000 to not only attack targets based on GPS coordinates, but to also insert a “man in the loop” who can manually place the bomb on target—or abort the strike if necessary. SPICE 1000 can glide up to sixty-two miles to target and is so accurate it can place half of all bombs within nine feet of their target.

The F-35 will also carry the Python-5 infrared air-to-air missile instead of the American AIM-9X Sidewinder. The missile’s ability to lock on after launch means the missile can be launched from the F-35’s internal weapons bay and lock onto enemy aircraft under its own power. Another IAF requirement was also to add a pair of 425-gallon fuel tanks to the Adir that extend the plane’s total fuel—and range—by approximately 36 percent. While the addition of an external fuel tank would compromise the F-35’s stealth, a source told Aviation Week & Space Technology the fuel tank could be used during early phases of an air operation where stealth was not necessary, and jettisoned after use.

The first F-35Is arrived in Israel in late 2016, with three more jets arriving in April 2017. According to Israeli Air Force officials quoted by the Times of Israel, the remaining forty-five planes will trickle out out every few months, and the first jets should become fully operational by October 2018. Israel plans to have two squadrons stood up and fully operational by 2021 or 2022. Given that the F-35I will replace literally hundreds of early model F-15s and F-16s, a second and even third order of planes seems likely, particularly when the price comes down to the projected goal of $85 million each for the -A model.

The F-35A might not be the only variant Israel purchases. In 2015, it was revealed the country was considering adding the F-35B, the vertical-takeoff-and-landing version of the jet, to the Israeli Air Force’s inventory. The missile threat posed by Israel’s neighbors, particularly Hezbollah, could temporarily shut down Israeli air bases across the country in wartime. The ability to disperse fighters to secret locations where they could use helicopter landing pads and stretches of freeway to take off and land is an attractive prospect.

The Israeli F-35, the Adir, already stands out from the rest of the international F-35 fleet. Real-world challenges could make it stand out in other ways: given Israel’s security situation the F-35I, like the F-15A forty years earlier, could very well be the first of its kind to enter combat.

Kyle Mizokami is a defense and national-security writer based in San Francisco who has appeared in the Diplomat, Foreign Policy, War is Boring and the Daily Beast. In 2009 he cofounded the defense and security blog Japan Security Watch. You can follow him on Twitter: @KyleMizokami.

Image: Flickr.