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The SUMS experiment complements SEADS by enabling measurement of atmospheric density above 300,000 feet. SUMS samples air through a small hole on the lower surface of the vehicle just aft of the nosecap. It uses a mass spectrometer operating as a pressure sensing device to measure atmospheric density in the high altitude, rarefied flow regime where the pressure is too low for the use of ordinary pressure sensors. The mass spectrometer, incorprated in the SUMS experiment, was spare equipment originally developed for the Viking Mars Lander. SUMS was previously flown on STS-61C and STS-35. Robert C. Blanchard and Roy J. Duckett of
Langley Research Center are co-principal investigators. Both SEADS and SUMS provide entry atmospheric environmental (density) information. These data, when combined with vehicle motion data, are used to determine in-flight aerodynamic performance characteristics of the orbiter.

The SEADS nosecap on the orbiter Columbia contains 14 penetration assemblies, each containing a small hole through which the nosecap surface air pressure is sensed. Measurement of the pressure levels and distribution allows post-flight determination of vehicle attitude and atmospheric density during entry. SEADS, which has flown on four previous flights of Columbia, operates in an altitude range of 300,000 feet to landing. Paul M. Siemers III, Langley Research Center, Hampton, Va., is the principal investigator.

The SILTS experiment will obtain high-resolution infrared imagery of the upper (leeward) surface of the orbiter fuselage and left wing during atmospheric entry on the shuttle Columbia (OV-102) Added for STS-61C, used on several missions after. Instrumentation was later removed but pod remained.

The Orbital Acceleration Research Experiment (OARE) under NASA's Microgravity Measurements and Analysis Project
(MMAP) will measure the space shuttle's on-orbit linear acceleration into the submicrogravity regime.