Star Technology and Research, Inc., is a small business located in the state of
South Carolina and organized to perform Small Business Innovative Research (SBIR) contracts. STAR, Inc. has computer
and analytical capabilities at its Mount Pleasant, SC location, and its remotely located employees are equipped with a variety
of desktop computers and the latest business and technical software. For specialized research and development, STAR,
Inc. subcontracts with educational and industrial organizations for the needed facilities. These include The Ohio State
University (OSU), Tether Applications, Inc. (TAI), and the Georgia Institute of Technology Research Institute (GTRI).
The Ohio State University (OSU)
The Aeronautical and Astronautical Research Laboratory (AARL) at OSU is the major fluid research
facility of the OSU Aerospace Engineering and Aviation Department. Established more than fifty years ago at the Ohio
State University airport, the facility and staff of AARL have a history of experimental aerodynamic facility and instrumentation
developments that include design and operation of the first continuous flow, heated air hypersonic wind tunnel and the first
arc-heated shock tube. Facilities include a blow-down 6”x6” supersonic wind tunnel, a 12”x12”
high Reynolds number wind tunnel, a 6”x22” low-turbulence transonic wind tunnel for airfoil tests, and a 3'x5'
subsonic wind tunnel—all built around a 4000-psi high pressure air compressor, a 12000-cfm vacuum pumping system and
a 2.5 MW electric power station.
The AARL has pioneered on-line data acquisition and
processing of the facility instrumentation systems, which include traditional pressure, force, and heat transfer measuring
equipment. Oil streak, smoke, and laser sheet visualization are also available. Data processing is
conducted with a Harris midi-computer and PC's as appropriate for specific tests. Access to SGI work stations and
the Ohio State Supercomputer from AARL are available for the more complex CFD aerodynamic calculations often necessary in
the AARL research. The subsonic wind tunnel to be used in this program is an open circuit facility with a closed 3'x5'
test section and a speed range from 20 ft/sec to 150 ft/sec. Three screens and a honeycomb in the stilling chamber contribute
to the low turbulence intensity level of the facility—less than 0.1%—providing excellent flow quality for aerodynamic
research. Instrumentation for the tunnel includes multiple PSI electronically scanned pressure transducers, a force
balance, wake survey probe and flow visualization equipment. The tunnel controls and data acquisition are computer driven
for simple, stand-alone, economic operation and on-line data processing. Recent work in this facility has addressed
insect contamination on wind turbine airfoils, unsteady aerodynamics and dynamic stall of airfoils and an on-going project
examining the three dimensional, unsteady stall characteristics of wings.
Tether Applications, Inc. (TAI)
TA has 600 ft2 of offices and lab space in Chula Vista,
just outside San Diego, and access to a separate facility in downtown San Diego. This 1500 ft2 facility has office space
plus a large high-bay area, used for machining, composites fabrication, and testing. Hardware fabrication and testing
is done at the San Diego facility, and space tether wire winding and some deployment tests are done in the Chula Vista facility,
which has the specialized computer-controlled winding and test equipment used to wind and deploy the SEDS, PMG, and TiPS tethers
for NASA and Navy space flights.
TAI has more experience in fabricating space tethers than any other company
in the world. TAI personnel developed the tethers and tether deployer systems (excluding the NASA-provided flight computer)
used in all four of the successful orbital flight tests of long tethers to date:
- SEDS-1 (3/93) Deployed
20 km of tether at low tension to deorbit a payload via tether
- PMG (6/93) Deployed 500 m of 18 gauge
insulated wire for Plasma Motor-Generator
- SEDS-2 (3/94) Stabilized a payload 20 km below the host vehicle,
with 4o residual swing
- TiPS (6/96) Tether Physics & Survivability: 4 km tether 2 mm in dia; intact
after 3 yrs
TAI has worked with NASA and industry to define and begin developing appropriate roles
for tethers on the International Space Station, including the NASA Marshall Tethered Reentry Experiment Vehicle (TREV).
This is a Delta-compatible test version of a Station Tethered Express Payload System (STEPS). As part of this project
TAI designed, built, and tested a smaller version of the SEDS deployer that fits inside the capsule itself. TAI also
developed the Small Intelligent Datalogger (SID) flight computer, and is also leading development of the ProSEDS tether and
a modified version of the SEDS deployer for NASA Marshall.
Georgia Institute of Technology (GIT)
Computational Aerodynamics and Aeroelasticity
GIT has a number of computing resources, including an SGI Origin 2000 machine with two
processors. Visualization is accomplished on SGI O2 graphics workstations. The COBALT code is used with the Gridgen
and FieldView systems to perform Euler and Navier-Stokes predictions of the air vehicle and winglet aerodynamics. A
Beowulf Cluster of 20 computers to form a distributed computing network came on line in 2001.
The John J. Harper 7’ x 9’ wind tunnel at the School of Aerospace Engineering has a vented atmospheric-pressure
test section that enables testing of larger models with minimal wall interference at speeds up to 165 mph. The free-stream
turbulence intensity is on the order of 0.3 to 0.5 percent. The test section offers strong advantages for optical diagnostics
and high-angle-of-attack testing, since the test section blockage problems and signal degradation through windows are minimized.
The facility offers point-wise, multi-component laser velocimetry with fiber-optic access, customized force measurement systems
with digital data acquisition, pressure measurement, and time-series /frequency domain data analysis software based on FFT
routines. Two new double-pulsed Nd-YAG laser systems and digital cameras enable periodic-flow Particle Image Velocimetry,
with GIT's SCV system. Silicon Graphics O2/Octane class workstations offer the ability to perform numerical work
related to high angle of attack aerodynamics and control. MatLab/Simulink™ simulation software is used for developing
Recent and ongoing projects at
the tunnel include studies of the origin of tip vortices at the tips of fixed wings and rotating blade tips, conducted using
optical diagnostic techniques such as single-point, phase-resolved Laser Doppler Velocimetry. Recent experience also
includes force measurements on a low-aspect ratio wing model to measure the effects of certain active-control devices.
Winglet effects on the forces, and the flowfield, were measured at this facility for STAR, Inc., using models and balances
built for their program in aircraft winglets. Strain-instrumented flexure balances were developed for both the high-sensitivity,
low-load regime of low Reynolds number testing, and for the robust environment of wing testing up to a chord Reynolds number
of 500,000. Laser sheet visualization using a pair of Nd-YAG video-rate lasers and wax smoke was used to capture and
quantify the trajectories of the vortices from the winglets.