baalke@mars.jpl.nasa.gov (Ron Baalke) (01/19/90)
RELEASE: 90-8 RESEARCH EXPERIMENTS TO MONITOR COLUMBIA RE-ENTRY During Columbia's fiery re-entry through Earth's atmosphere at mission end, two experiments will measure the orbiter's aerodynamic and thermodynamic characteristics to acquire data for future space transportation systems. STS-32 is the third flight of the Shuttle Infrared Leeside Temperature Sensing (SILTS) and the Shuttle Entry Air Data System (SEADS) experiments, developed by Langley Research Center, Hampton, Va., in NASA's Orbiter Experiments (OEX) program. The OEX program conducts atmospheric entry research during the Shuttle orbiter's return from space. OEX experiments are placed within the orbiter structure for data collection, leaving the payload bay free to support the flight's primary payloads. SILTS and SEADS previously flew on STS-61C in January 1986 and on STS-28 in August 1989. On STS-32, SILTS will gather additional data to predict thermal protection requirements for the upper surfaces of advanced entry vehicles. As Columbia slows from orbital speed down to about Mach 8 (eight times the speed of sound), an infrared camera located in a pod at the tip of the orbiter's vertical tail will gather high-resolution infrared imagery of the upper (leeward) left wing. Researchers will use the data to produce detailed thermal maps showing the magnitude and distribution of aerodynamic heating. On STS-28, SILTS images revealed increased temperatures just behind the leading edge of the wing and in an area between the inboard and outboard elevons flight control surfaces which reached around 1,100 degrees Fahrenheit. Prior to the experiment's next flight on the STS-35 mission scheduled for April 1990, the experiment will be reconfigured to monitor Columbia's upper fuselage. The SILTS results are vital to the design of advanced winged spacecraft because each pound of unnecessary thermal protection that can be eliminated allows another pound of payload to be carried for the same launch cost. Moreover, SILTS collects data under flight conditions that can not be duplicated in ground- based facilities. SEADS is housed in Columbia's nosecap. The experiment incorporates 14 penetration assemblies distributed about the nosecap surface, each containing a small port through which local surface air pressure is measured. Measurement of air pressure distribution allows precise post-flight determination of "air data" such as angle of attack, angle of sideslip, free stream dynamic pressure and Mach number. Accurate information on these factors, coupled with vehicle motion information measured by a separate experiment, are required to determine the orbiter's aerodynamic flight characteristics. SEADS provides accurate data during ascent from liftoff to about 56 miles and from that altitude through landing during re-entry. The principal technologists for SILTS are David A. Throckmorton and E. Vincent Zoby of Langley's Space Systems Division. Paul M. Siemers III of the Space Systems Division is the principal technologist for SEADS. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 |