UW Star Tracker guides another rocket into space

December 19th 2009
Natural & Physical Sciences
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Dr. Percival (2nd from right) standing in front of the rocket that was launched the following evening, carrying the ST5000.
Dr. Percival (2nd from right) standing in front of the rocket that was launched the following evening, carrying the ST5000.

Astronomers sometimes need to use telescopes that are in space because the Earth's atmosphere blocks ultraviolet and X-ray light.

NASA's sounding rocket program sponsors astronomers and graduate students to build telescopes that can be launched into short (15 minute) sub-orbital flights that generate enough data for Ph.D. dissertations.

These rockets need to be pointed at their targets very quickly and very accurately.

Dr. Jeffrey W Percival and the technical staff of the Department of Astronomy's Space Astronomy Laboratory have invented a device called the "Star Tracker 5000," which in seconds calculates the rocket's orientation using whatever stars it first sees and then guides the rocket to its celestial target.

NASA has licensed this invention from UW-Madison for use in the sounding rocket program. The accuracy and speed of the ST5000 represents a generational leap in rocket guidance.

On November 13th, the ST5000 flew again on its 7th mission from the White Sands Missile Range in New Mexico, guiding a University of Colorado experiment.

The flight was a complete success, with the ST5000 capturing an image of the sky, analyzing the initial star pattern, and computing the rocket's position and direction in a record 6.5 seconds, with a precision of about an arcsecond. This was followed by 368 seconds of X-ray observations of gas ejected from a long-ago supernova in the constellation of Cygnus the Swan.