HANCOCK COUNTY, Miss. -Every Space Shuttle Main Engine (SSME) undergoes
testing at Stennis Space Center. During these tests, engineers record
instrumentation measurements
for engine performance analysis. A NASA Dual-use Technology Development
Program product that
records dynamic data directly to a computer disk instead of to magnetic tape
has reduced system
maintenance and improved delivery of the data product.

"During an engine test, we record both high- and low-speed test data," said
NASA’s Randy
Holland, electrical design and analysis lead engineer with the Propulsion
Test Directorate (PTD) at
Stennis. "Static pressures, for example, change in milliseconds during an
engine test and are
considered low-speed data. High-speed dynamic measurements, such as
acceleration, change
considerably faster, in microseconds, and require specialized acquisition
and recording systems."

To monitor engine test dynamic data, SSME rocket test engineers once
recorded all high-
speed data onto specialized magnetic tapes. The tapes, however, required
high maintenance on the
recorders, and processing the information into usable data was time
consuming. The Taxi-100 Direct
to Disk system, developed by Integrated Systems consultants (ISC) of San
Jose, Calif., and Omni
Technologies of New Orleans, La., is an interface system that uses fiber
optics to transfer high-speed
dynamic data from an engine test directly to a computer disk drive. The new
system eliminates the
need for tape, thus saving the time it takes to transfer the data from tape
to disk, and reduces
maintenance costs, particularly for the high data volume from long duration

The Dual-use Technology Development Program is based on the sharing of
costs, risks and
successes between the government and a commercial partner. In dual-use
projects, NASA contributes
unique facilities and knowledge, engineering resources and funding. In turn,
the commercial partner
contributes its unique resources, facilities, manufacturing and marketing
capabilities, and potential

"The Taxi-100 system is saving the Propulsion Test Directorate time and
money, and helping
them provide a better product," said NASA’s Kirk Sharp, manager of the
Office of Technology
Transfer at Stennis. "In addition, the product has been made commercially
available, making it an
excellent example of a dual-use success." The system may also be applicable
at other rocket test
facilities that could benefit from increased efficiency in repetitive
high-volume data handling

The evaluation of high-speed, or dynamic, data is critical to the evaluation
of engine
performance. "We record dynamic conditions like pressure to evaluate
combustion stability," said
NASA’s Lee Johns, instrumentation engineer at Stennis. "What we’re trying to
avoid are oscillations
that cause disruptions or damage, and, in turn, compromise safety and

Stennis engineer Paul Lagarde of Boeing Rocketdyne directed the systems
integration of the
Taxi-100 in the A-Complex. "What used to take hours now takes minutes," said
Lagarde. "This
system has dramatically improved the quality of the high-speed data
acquisition product and provided
some tools with which the health of the system can be determined in a more
timely manner." The
time and labor saved by the Taxi-100 system also translate into cost

"We enjoyed doing business with NASA," said Bruce Newnan of ISC. "We worked
with very
smart people and produced a new product for NASA which otherwise would have
been shelved. The
dual-use contract mechanism is an effective tool to transfer ideas to

For more information on the NASA Dual-Use Technology Development Program at
call (228) 688-1929, or access the Web site at