BOUNDARY LAYER TRANSITION, DETAILED TEST OBJECTIVE 854 (BLT, DTO 854)
Research Area: Technology Development and Demonstration: Spacecraft and
Orbital Environments
Expedition(s): 18- 20
Principal Investigator(s): ● Gerald Kinder, The Boeing Company, Huntington Beach,
California
● Charles H. Campbell, NASA’s Johnson Space Center, Houston,
Texas
RESEARCH OBJECTIVES
The Boundary Layer Transition (BLT) involves the use of 10 modified tiles, equipped with
thermocouples (indicate a temperature change based on voltage between a junction of 2
different metals), placed on the bottom of Space Shuttle Discovery’s left wing. One tile is also
equipped with a protuberance (specially modified speed bump) to study the characteristics of
how the airflow is tripped from laminar (smooth) to turbulent (rough) during re-entry. BLT
improves the understanding of the parameters associated with re-entering the atmosphere and
including the significant heat increase caused by turbulent boundary layer flow.
EARTH BENEFITS
BLT provides scientists and engineers with the
incredible opportunity to demonstrate how NASA is
working to understand spaceflight better and an
opportunity to successfully apply what has been
learned to improve space vehicles.
SPACE BENEFITS
The data gathered from BLT will be utilized to
support analytical computer modeling and design
efforts for the space shuttle and NASA’s next
generation spacecraft.
RESULTS
The Boundary Layer Transition (BLT) was successful in obtaining BLT onset data near Mach 16
and turbulent heating data after Mach 16 with a 0.25 inch tile protuberance downstream of the
port landing gear door. Flight hardware performance and thermocouple data was excellent, and
no anomalies were identified.
This investigation is complete; however no publications are expected.
STS-119 Post-flight image of BLT.NASA image.