With Seoul’s March 24 announcement of its long-held intent to purchase the F-35A, South Korea is likely securing an offset deal that will include a new military communications satellite and technical assistance in the country’s plans to develop an indigenous stealthy KF-X fighter.

Lockheed Martin, the sole producer of stealthy fighters globally, will provide more than 300 man-years worth of engineering expertise in assisting Seoul in designing its KF-X. The F-22 and F-35 builder will also offer more than 500,000 pages of technical documentation derived from the F-16, F-22 and F-35, says Michael Rein, a company spokesman.

South Korea is looking at multiple KF-X designs, but has recently found that a single-engine option may be as effective at an affordable price point as a twin engine. It is slated to become operational around 2025.

Also in the offset proposal is a secure satellite communications satellite; Lockheed is building the newest U.S. Air Force jam-proof satellite called the Advanced Extremely High Frequency spacecraft. It is built on the company’s A2100 bus and includes the latest security measures to avoid interference or jamming. The offset also includes “necessary control equipment and technical training,” Rein says. The deal could cover delivery of the new satellite, launch and turnover of the operational system.

Seoul announced its choice of the F-35A over the Eurofighter Typhoon and Boeing F-15 Silent Eagle, a Strike Eagle modified with stealthy weapons bays and leading edges, in December. Though Boeing’s offer was the only one to comply with South Korea’s budget limitations, the government overrode a recommendation to buy the Super Hornet. To stay in a budget of 8.3 billion won ($7.2 billion), the country is only purchasing 40 F-35As, far less than its intended buy of 60 aircraft in the F-X phase 3 program.

Lockheed Martin also included development of a virtual warfare center to be used for modeling and wargaming in its offer. However, since the deal was cut to 40 aircraft, there could be changes to the plan, one industry official says.

South Korea is the 10th country that has announced its intentions to buy the F-35. Israel and Japan committed in 2010 and 2011, respectively. Seoul’s sale will make use of the Pentagon’s foreign military sales program. It is widely assumed that the country will include an option of the additional 20 fighters in its program for purchase on a later date.

South Korea plans to take delivery of its first F-35As in 2018; they will be included in the Pentagon’s low-rate, initial production buy. Seoul plans to buy as many as 10 per year.

The final agreement on the buy is expected to be signed by year’s end, says Steve O’Bryan, vice president of program integration and business development at Lockheed.