Alicat Scientific Product Catalog - Alicat Scientific - #4

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www.AlicatScientific.com 2 Alicat Scientific is ISO 9001:2000 certified •• lifetime warranty Alicat’s PC Series Pressure Controller Alicat Scientifi c, Inc. 7641 N Business Park Drive Tucson, AZ 85743 USA Phone: 888 290 6060 Fax: 520 290 0109 Payload sections of some NASA rockets are required to achieve pointing accuracies fi ner than one arc second (1/3600 degree). Conventional attitude control systems introduce too much shock and vibration to be used with delicate instruments. Alicat Scientifi c was asked to help solve this problem. The solution utilizes modifi ed Alicat PC Series absolute pressure controllers to directly feed the attitude control jets. Alicat’s standard multi-drop RS-232 is used to send set-point commands to the controllers. The spacecraft’s attitude is adjusted by modulating the pressure commands to the controllers. Pressures can be changed in increments as small as 0.00234 PSI or as large as 150 PSI. Crucial to the success of the system is the speedy response of the Alicat instruments. NASA tests showed that the controllers accurately track a 5 Hz sign wave – a response faster than 32 mS. The controllers also passed NASA testing for vibration, shock, thermal cycling and exposure to vacuum. The fi rst fl ight took place in June 2007. The controllers performed perfectly. For more about Alicat Pressure Measurement and Control Instruments turn to pages 29 to 35. SMALL DEVICES FOR BIG PROJECTS! NASA Payload Attitude Control System Uses Alicat Pressure Controllers www.AlicatScientifi c.com