Press Release

Scientists’ Innovation Leads to U.S. Patent Award and a Competitive Boost for Boeing Satellite Systems

By SpaceRef Editor
July 30, 2001
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Star-Tracker Breakthrough Helped Company Capture Major NASA Contract

A deceptively simple
innovation has led to a U.S. patent award as well as significant
business benefits for Boeing Satellite Systems (BSS), the world’s
largest satellite manufacturer. The invention — a new method of
positioning optical star trackers on satellites — enables BSS to
achieve extremely precise determination of spacecraft attitude. This
technology helped BSS win a significant U.S. government
weather-satellite contract and meet the demanding design requirements
for the Spaceway broadband satellite system being built at BSS, a unit
of The Boeing Company.

For this invention, BSS scientists Yeong-Wei “Andy” Wu, Douglas H.
Hein and David L. Augenstein, along with Garry Didinsky, a former BSS
employee, received U.S. Patent 6,236,939, “Method and apparatus for
controlling spacecraft attitude with rotational star trackers.”
Spacecraft attitude describes the orientation and position of the
satellite relative to the earth’s surface. Their work advances the
field of stellar inertial technology, which involves the use of star
trackers rather than earth sensors to achieve up to 50 percent greater
pointing accuracy for satellites in orbit. This patent is one of more
than 20 stellar inertial systems patents that BSS scientists have
received or are submitting.

“I am extremely proud of Andy, Doug and David for their role in
this innovation, which has given us an important competitive
advantage,” said Randy H. Brinkley, president of Boeing Satellite
Systems. “Spacecraft attitude must be tightly controlled for the
next-generation GOES weather satellites we’re building for NASA, and
for high-frequency Ka-band spacecraft such as Spaceway, which uses
multiple spot beams to fulfill its mission requirements. What’s more,
Spaceway will mark the first uses of stellar inertial technology for
attitude control aboard a commercial geosynchronous spacecraft.”

Star trackers are on-board telescopes that scan areas in space and
digitally record the position and brightness of stars. Processors
aboard the spacecraft compare those images with star maps in memory to
determine the spacecraft’s exact attitude and position. That
information helps ground controllers to more precisely orient the
satellite for maximum pointing accuracy.

However, distortions in the trackers’ optical components have
traditionally led to a relatively high level of errors that lessened
the accuracy of the star tracker images.

“The innovation covered by the star tracker patent is both simple
and profound. The co-inventors discovered that, by rotating the star
tracker 45 degrees so that imaged stars cross its pixels on a diagonal
path, errors in the images were reduced by approximately 50 percent,”
explained Loren Slafer, a BSS chief technologist. “That reduction in
image errors allows for the precision pointing accuracy called for in
a number of leading-edge satellite systems being built here at BSS.”

Slafer added that their work was part of intensive internal
research and development efforts mounted to give BSS this technical
capability, and it is now being used on a number of programs,
especially GOES, which stands for Geostationary Operational
Environmental Satellites. BSS is currently under contract to build
GOES N through GOES Q in the alphabetical series. Based on the highly
successful Boeing 601 spacecraft, the new GOES satellites will provide
more accurate location of severe storms and other weather phenomena,
resulting in more precise warnings to the public. The next spacecraft,
GOES N, is scheduled for launch in 2003.

The company also built GOES D through GOES H, but NASA later
awarded GOES I through GOES M to another contractor. “This patent
really gave us the edge, and helped us take GOES back from the
incumbent,” Wu said.

BSS’ development of stellar inertial attitude-determination
systems over the last five years has resulted in more than 20 BSS
patent applications, with three patents awarded so far.

“Together these patents represent a gold mine of innovative ideas
that have improved the state of the art in stellar inertial systems,
and we are applying them on five major satellite programs to date,”
Hein said.

Boeing Satellite Systems is the world’s leading manufacturer of
communications satellites and a major provider of space systems,
satellites, and payloads for national defense, science and
environmental applications.

The Boeing Company is the largest aerospace company in the world
and the United States’ leading exporter. It is NASA’s largest
contractor and the largest manufacturer of commercial jetliners and
military aircraft. The company’s capabilities in aerospace also
include rotorcraft, electronic and defense systems, missiles, rocket
engines, launch vehicles, satellites, and advanced information and
communication systems. The company has an extensive global reach with
customers in 145 countries.

SpaceRef staff editor.