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:: Experience & Expertise :: Khalstar Tracker - High Accuracy Star Tracker ::
Technical Description
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The Khalstar Star Tracker is specifically designed as the precision attitude knowledge reference for the GIFTS/IOMI payload suite. This new generation Star Tracker is the latest design originating from Texas A&M.s Spacecraft Technology Center, and patented by Drs. John Junkins, Thomas Pollock and Daniele Mortari. The Khalstar Star Tracker is now commercialized by Broad Reach Engineering and is available for a variety of space missions requiring attitude knowledge of better than 5 arc-secs in all axes. The Khalstar is a two-headed tracker, which enables precision accuracies in all axes without the need to fly two individual trackers. The Khalstar contains a single telescope and a single detector, though two orthogonal image boresights and two sunshade/baffles. Since a single focal plane, electronic sub-system, power sub-system and processor are required, the two-headed tracker design offers significant advantages in mass, power, and cost in comparison to using two conventional trackers to achieve comparable accuracy.
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Heritage
The Khalstar Star tracker is based on a legacy of advanced attitude determination algorithms developed at Texas A&M University including recursive on-orbit calibration, unique star pattern identification using K-vector tables, and the Lost In Space Algorithm (LISA) recently demonstrated on the STS-107 flight. The optical system employs radiation tolerant glass and a thermally compliant mounting system previously flown in space. The electronic architecture is based on a flight proven designs for command and data handling. All components are Grade 1 parts selected for long life in GEO.
Performance
The following table illustrates the performance parameters of the Khalstar Tracker:
| Characteristic |
Performance |
Description |
| Accuracy with IMU (3 axis) |
2 arc-sec |
Up to 100Hz rate |
| Accuracy without IMU (3 axis) |
5 arc-sec |
Up to 10 Hz rate |
| Power Consumption at 100 Hz |
13 W |
28 V input |
| Power Consumption at 10 Hz |
5 W |
28 V input |
| Mass |
<3.0 Kg |
Including light shade |
| Size (with light shade) |
28.7 x 17.8 x 47.2 cm |
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| Time to acquire quaternion |
1 second |
No a priori knowledge |
| Maximum slew rate to acquire |
TBD |
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| Magnitude of Stars |
5.5 |
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| Meantime Between Failures |
TBD |
Estimated |
| Active Field of View |
8 x 8 degree square |
Total volume |
| Baffle/Light Shade Field of View |
25 degree cone |
Application specific |
| Radiation Tolerance |
>100Krad |
Latch up Immune |
For more informationm please contact:
Dr. David Boyle
Director, Spacecraft Technology Center
Room 102F, University Services Building
Texas A&M University (MS 3118)
College Station, TX 77843-3118
tel: 979.845.8768
fax: 979.847.8857
dboyle@tamu.edu
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