2016.B.3.4. Development of 50mN class hydrogen peroxide monopropellant microthruster for cube satellite applications
Jeongmoo Huh (1)
Sejin Kwon (1)
- Korea Advanced Institute of Science and Technology, Republic of Korea
Microthruster, monopropellant, hydrogen peroxide, green propellant, MEMS fabrication process
This work reports a 50mN class liquid microthruster using hydrogen peroxide as a monopropellant. Monopropellant propulsion has higher specific impulse performance than cold gas propulsion, and simpler system than bi-propellant propulsion. In addition, it has throttling and reignition abilities which are essential function for cube satellites operations, but these are difficult using solid propellant propulsion. Monopropellant thruster has catalyst chamber for propellant decomposition. Most of previous work for monopropellant microthruster showed insufficient propellant decomposition efficiency stemming from excessive heat loss in micro scale thruster.
In this work, 50mN class monopropellant microthruster was developed using glass, one of the most insulating material to reduce heat loss of micro scale thruster. A green propellant 90wt% hydrogen peroxide was used as monopropellant. Platinum/alumina catalyst was fabricated and used for propellant decomposition in the chamber. Microthruster was fabricated using photosensitive glass MEMS process and. Nine photosensitive glass wafers were wet etched and patterned with microthruster components. Integration process was conducted using thermal and UV bonding after inserting fabricated platinum/alumina catalyst into the microthruster chamber.
Experimental test was conducted with syringe pump, Teflon tubes, valves, temperature, pressure, force transducers and data acquisition equipment. Performance test result showed successful operation of fabricated microthruster with average chamber temperature of 583˚C and pressure of 2.2 bar. With propellant supplying tubes and several sensors attached to the microthruster, force measurement had low accuracy and it was estimated as approximately 50 mN using measured chamber pressure and 1D isentropic flow assumption though nozzle. Rising time to reach 90% steady chamber pressure was approximately 3 sec. Temperature efficiency was calculated using measure chamber temperature and it was 77% based on the adiabatic temperature.
Although the rising time needs to be improved, liquid microthruster was successfully fabricated using photosensitive glass MEMS process, and performance was experimentally evaluated using hydrogen peroxide as a monopropellant. The result is expected to further liquid monopropellant technologies for cube satellite applications including orbit transfer, attitude control and drag compensation.
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