National Institute of Standards and Technology
Gaithersburg, Maryland

Media Contact:
Laura Ost, (301) 975-4034

September 9, 2005

NIST Shielding Data Help Launch Shuttle

As the National Aeronautics and Space Administration (NASA) plans for
the next launch of the space shuttle, a critical aspect of the program's
safety is being assured by 5 million pieces of data collected recently
by the National Institute of Standards and Technology (NIST).

To help prevent a repeat of the 2003 accident when launch debris damaged
the shuttle Columbia, causing it to break up on re-entry, NASA has begun
illuminating shuttles with tracking radars during launches and ascent to
detect and quantify potential hazards. Concerns about possible
disruption of onboard electronic guidance and control systems led NASA
to request NIST's help in determining how much radar energy can
penetrate the orbiter in key locations.

During the launch of Discovery in July, radar was used to track debris
during ascent and NASA considered the NIST shielding data vital to the
resumption of shuttle flights.

NIST has been conducting research in this area for several years and has
developed a portable system that efficiently measures the
electromagnetic shielding characteristics of airframes. The system
previously has been used to evaluate both commercial and military
aircraft. NIST engineers visited the Kennedy Space Center in Florida to
evaluate the space shuttle Endeavor and the hanger in which the
measurements were made.

The NIST system incorporates ultra-wideband antennas, a precision
optical link between them, and a computerized data analysis system. The
two-step measurement process consisted of a reference measurement with
the transmitting and receiving antennas outside the shuttle, and a
penetration measurement with the receiving antennas at selected
locations inside the orbiter. A computerized comparison of these two
measurements over specific time periods and frequency bands provided a
measure of shielding characteristics in the frequency range 30 megahertz
to 6 gigahertz. The data enabled NASA to set safe power levels on radar
systems used to detect debris.

IMAGE CAPTION:
[http://www.nist.gov/public_affairs/i...ielding_HR.jpg
(2MB)]
NIST researchers Dennis Camell (left), Chriss Grosvenor (on the ground),
and Nino Canales assemble an antenna tower used in the NIST system for
measuring the space shuttle's electromagnetic shielding.

Image credit: Photo by David Novotny/NIST