Our Mission: 'To make our industry quieter, safer and greener'
Our client required a solution to enable air‑breathing rocket motor testing at an existing test facility located and operated within an urban environment. The facility is situated approximately 400–600 meters from nearby residential areas, with strict local limits on instantaneous daytime noise levels.
To support future growth of the test programme—including an increased number of tests and higher‑power rocket testing—effective noise mitigation was essential, both to protect the surrounding environment and to maintain a safe and comfortable working environment on site.
Our client commissioned an acoustic concept design to identify a practical, compliant, and flexible noise mitigation solution that would allow their testing programme to expand.
Key Acoustic Challenges
Extremely High Noise Levels from Rocket Testing
Air‑breathing rocket motors generate very high sound power levels, particularly at low frequencies, making effective attenuation technically challenging.
Proximity to Residential Areas
The facility’s location within a populated area meant even short‑duration tests could result in noise complaints even if noise limits were not exceeded.
Tight Site and Structural Constraints
Operational Flexibility Requirements
The acoustic solution needed to be removable and re‑deployable, allowing occasional solid rocket testing and future site reconfiguration without major civil works or specialist lifting equipment.
Limited Measured Data for Higher‑Power Rockets
Measured acoustic data existed only for lower‑power tests, requiring reliable extrapolation to ensure compliance for rockets up to 12 MW.
Acoustic Solution & How Challenges Were Overcome
Advanced Acoustic Modelling & Validation
A validated 3D acoustic model was developed using industry‑leading software. Existing measured data was used as a baseline and conservatively extrapolated to represent higher‑power rocket tests, ensuring robust design margins.
Background Noise Surveys
Detailed background noise measurements were undertaken at multiple site boundaries to accurately assess real‑world community impact and ensure predictions reflected existing ambient noise conditions.
Bespoke Detuner System Design
A purpose‑designed, air‑cooled rocket exhaust detuner system was developed, drawing on proven principles used in military aircraft test facilities. Key features included:
Space‑Efficient & Removable Design
The system was mounted on a skid frame with adjustable wheels, allowing it to be positioned, removed, and stored using existing on‑site forklift equipment—avoiding cranes or specialist installation teams.
Noise reduction
Predicted noise levels demonstrated that the mitigated facility would reduce the noise by approximately 30 dB(A) with overall community impact estimated at only 0.5–4 dB above background noise.
Outcome
This project demonstrates how detailed measurement, advanced modelling, and practical acoustic engineering can successfully resolve highly challenging noise problems, even in sensitive urban environments.
