Turbulent airflow over and inside SOFIA's telescope cavity impacts the quality of the telescope's performance. To limit airflow interaction with the telescope, engineers used NASA supercomputers and wind tunnel testing to develop a solution that minimizes disturbances inside and above the telescope cavity. This solution also incorporates the upper rigid door and its tracks into the design.
When looking toward SOFIA's tail, one can see that a ramp was installed ahead of the telescope cavity that directs airflow up and over the forward door track, then over the telescope cavity. Another ramp guides airflow back along the fuselage toward the tail.
Some airflow does separate and enter the telescope cavity, however, an airflow ramp was added inside, at the aft end of the cavity, to direct airflow up and out of the cavity. This device is known as the "telescope cavity aperture."