The Airforce has been trying over the years to develop a new technology that could make this type of communication possible. Up until recently, the F-22 couldn't transmit stealthy data to any aircraft besides other F-22s. The F-35s also couldn't communicate with the F-22s except at the voice level. All because each aircraft used different Low Probability of Interception (LPD/LPI) communications.
Project Hydra marked the first time when F-35 sensor data was transmitted to an operational ground system via a Tactical Targeting Network Terminal (TTNT) by using an airborne gateway. Its core is based on an Open Systems Gateway (OSG) payload installed in a U-2 Dragon Lady. This system also helps F-22, F-35, TTNT and Link-16 connections. The F-35 sensor data was used as well to perform a simulated fire exercise.
The U-2 enabled the six aircraft to communicate with each other and with global command and control units even when they were out of the line of sight. Data was shared to command and control (C2) nodes like the Common Mission Control Center using the U-2's line-of-sight (LOS) and beyond-line-of-sight (BLOS) data link capabilities (CMCC).
Project Hydra reached a milestone, making the communication between F-35s and F-22s possible after many attempts. This flight test's success also demonstrates progress in data-sharing across the Air Force, as well as other branches of the U.S. military.