NASA, specifically the Controls and Dynamics branch at GRC, is actively engaged in Active Combustion Instability Control research. NASA is currently focusing on low emission lean-burn combustor design along with the application of ACIC techniques to increase the operating range of said combustors. The proposed harsh environment valves enable the application of the ACIC techniques due to the fact that the actuators, being closed-coupled to the fuel injector, have the required flow modulation control authority to implement the control schemes. Operational gas turbine combustors, including augmentors, are prone to thermoacoustic instabilities. Therefore, companies such as GE, PW and Rolls Royce, are actively investigating ACIC. The valves developed for the lean-burn combustor fuel control can also be used to provide the control authority required to implement ACIC techniques into existing product lines of not only the gas turbine manufactures listed above, but other engine manufacturers as well.