Date of Graduation

8-2011

Document Type

Thesis

Degree Name

Master of Science in Microelectronics-Photonics (MS)

Degree Level

Graduate

Department

Microelectronics-Photonics

Advisor/Mentor

Huang, Po-Hao Adam

Committee Member

Fritsch, Ingrid

Second Committee Member

Ulrich, Richard K.

Third Committee Member

Vickers, Kenneth G.

Keywords

Attitude control; Mems; Microscale; Nanosat; Satellite; Thruster

Abstract

A microscale gas generating chip has many applications; in this study, applications relating to picosatellites have been considered. Cube satellites, a type of picosatellite, are of mass around one kilogram and side length 10cm x 10cm x 10cm. Their launches are becoming more numerous since their debut ten years ago. Their low cost and deployment system makes space accessible to agencies hitherto barred from it, such as universities and small governments. However, their power, mass, and volume budget is extremely tight. A microscale gas chip could compete with other designs for attitude control devices, most not flown yet as cube satellites are a new technology. Secondly, as pico and nanosatellite launches become more numerous, there is a concern that they will flood space with debris which will damage other, more valuable articial satellites. Recognizing this problem, international and US standards limit the lifetime of a cube satellite to 25 years after end of mission. Again, a low mass, power, and volume device is required in a cube satellite to deorbit and not take valuable resources away from a scientific payload. A MEMS (micro-electro-mechanical systems) chip for attitude control, with impulse bit on the order of uNs and total impulse of tens of mNs per square centimeter, is presented. Also presented is a hybrid printed circuit board (PCB) and microfabricated chip suitable for inflation of a deorbiting balloon. This has advantages in mass and volume over a pressurized gas chamber. The chip functions by decomposition of solid sodium azide by an addressable heater array. Arrays of square wells, filled with propellent, of side lengths from 50 micrometers to 1 centimeter were fabricated. Heater arrays of up to 10x10 were fabricated and the feasibility of large (500x500) arrays is discussed. Considering the volume the gas would take at standard temperature and pressure, the microscale chip would produce gas amounts on the order of milliliters per square centimeter, releasable in microliters, requiring milliWatts. The larger, PCB-based chip produced tens of milliters of gas from a 1.25" x 1.25" x 0.07" chip, requiring 10 Watts of power for tens of seconds to actuate.

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