Press Release

EMS Technologies Announces Launch of New Star Tracker System On NASA Discovery Mission

By SpaceRef Editor
September 27, 2001
Filed under , ,

First Production Units Now Launched on Genesis To Provide Better Attitude-Tracking Capabilities in Space

EMS Technologies, Inc. is
announcing today the successful launch of the first production units of its
new CALTRAC® Star Tracker system aboard the NASA Discovery mission, Genesis.
The two-year mission will collect samples of the solar wind expelled by the
Sun, to help scientists better understand the make-up of the solar system.

The most significant instruments in the Guidance and Navigation Control
System are the pair of EMS CALTRAC Star Trackers, which perform a critical
role in spacecraft attitude control.
The CALTRAC Star Tracker was developed
by the EMS Space & Technology Optical Products Group in Ottawa, Ontario.
is a small, compact instrument, incorporating optics, detector, signal
processing electronics, power supplies and the tracker structure in a single

“EMS Technologies is pleased to provide a high-speed, fully autonomous
star tracker that can assist NASA’s experimental requirements and assure that
satellites maintain proper attitude continually while in flight,” said Martin
Lihou, director, Commercial Instruments, EMS Space & Technology Group.

The CALTRAC Star Tracker is an innovative spacecraft attitude-sensing
instrument that combines the precise attitude determination capability of a
traditional star sensor with the high-speed response normally associated with
gyros, scanning earth sensors, and sun sensors.
This allows the CALTRAC star
tracker to perform a wider range of roles than traditional star sensors, from
attitude recovery/acquisition through to precision attitude tracking.
With a
wide field of view, the CALTRAC unit provides a low noise celestial attitude.

This performance is the result of implementing a variety of performance-
enhancing technologies.
Chief among these is the use of special hardware-
based image processing techniques that permit stars to be located in real-time
without software assistance.
The unit is fully autonomous, providing
celestial attitude information based upon real-time star images.

“In 2000, the EMS Star Tracker system performed exceptionally well on an
experimental basis during two NASA Space Shuttle Atlantis missions, STS-101
and STS106, providing both a high data rate and extremely accurate tracking
for long periods of time,” commented Martin Lihou.
“The system has
demonstrated that it can meet critical navigational requirements in the rugged
environment of space.”

About EMS Technologies, Inc.

EMS Technologies, Inc. is a leading innovator in the design and
manufacture of wireless and satellite solutions, and focuses its unique range
of advanced technologies on the needs of broadband and mobile information
The Company is headquartered in Atlanta, employs almost 2,000 people
worldwide and has manufacturing facilities in Atlanta, Brazil, Montreal and
For more information, visit EMS on the World Wide Web at .

SpaceRef staff editor.