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A National Oceanographic and Atmospheric Administration Lockheed WP-3D made a series of flights off the eastern coast of Florida and from Edwards Air Force Base in a cooperative program with the Ames-Dryden Flight Research Facility (now the Dryden Flight Research Center, Edwards, California) in 1987 to test in-flight rain damage to the Space Shuttle thermal protection system. Dryden performed its tests with an F-104 aircraft over the facilities at Edwards, California. Both sets of tests were done at the behest of NASA’s Johnson Space Center, Houston, Texas. These tests revealed that damage can occur to the Shuttle’s thermal protection system during flight in rain. This is a concern, since such damage could compromise flight safety for the Space Shuttles and would certainly affect costs of operation and schedules.

Sections of the Space Shuttle thermal protection system’s 6- by 6-inch tiles were mounted on a pylon under the right wing of the WP-3D aircraft. The aircraft was equipped with raindropsize-measuring instruments and cloud radars. The WP-3D weather research aircraft obtained rain impact data for airspeeds between 180 and 260 knots indicated airspeed. Test samples were mounted on two movable doors contained within the left and right sides of the test fixture (for a total of four doors). The doors could be opened or closed to the free-stream airflow during flight at angles of 0, 15, 30, 45, and 60 degrees.

The WP-3D tile testing concentrated on observing the effects of larger drops of moisture at lower speeds. The principle investigator for the tile tests was Robert R. Meyer, Jr., NASA engineer, Ames-Dryden Flight Research Facility.

The Department of Commerce WP-3D aircraft was based at the Miami International Airport. It served as an environmental research platform for oceanographic and atmospheric studies by various government agencies and universities. The WP-3D flown in the Shuttle tile tests was specially instrumented for scientific observation with three radars and an onboard data recording capability. The pylon used for the tile tests could be configured so that specialized equipment could be installed for different users in the scientific community.