The Mars Helicopter, developed by the Jet Propulsion Laboratory and attached to the M2020 rover, aims to be the first aircraft to fly on another planet. It is a high-risk, high-reward project with the objective to prove that autonomous, controlled flight can be executed in the extremely thin Martian atmosphere. Testing the Helicopter on Earth required a vacuum chamber both capable of reaching Mars atmosphere conditions and large enough to accommodate the Helicopter’s test flights. The only available option was the JPL solar simulator, a 47’ tall, 25’ diameter vacuum chamber meant to provide environmental testing for JPL’s largest spacecraft. The solar simulator includes a 23’ diameter focusing mirror suspended 4 stories above ground level to direct energy onto spacecraft in the chamber. If this mirror is contaminated, JPL loses its capability to provide solar simulating capability to its largest spacecraft until the mirror is pulled down and carefully cleaned. The sensitivity of the solar simulator at JPL necessitates careful vetting of materials entering into the chamber. For most flight projects, the major assemblies entering the chamber are made of vacuum-compatible materials. The Mars Helicopter project constructed a wind tunnel in the solar simulator to provide airflow over the Helicopter engineering model in a Mars pressure environment. The wind-tunnel assembly was constructed from Commercial Off The Shelf (COTS) components without clear material documentation. The JPL Contamination Control group analyzed all major materials with Direct Analysis Real Time Mass Spectrometer (DART-MS), measured component outgassing after bakeout with a quartz crystal microbalance (QCMs), and estimated contamination impact to the solar simulator from the wind tunnel assembly. Contamination Control also implemented mitigation steps for COTS components, including material substitution, bakeouts, and cleaning. This approach overcame long-standing rules of thumb about the type of components that can enter the solar simulator, and can be used as an example when vetting COTS components for use in a vacuum environment with contamination sensitive surfaces.