STUDY ON IMPULSE BIT INCREASE BY MODIFICATION OF PPT CONFIGURATION

摘要

In Tokyo Metropolitan Institute of Technology (TMIT), presently Tokyo Metropolitan University, PPT-B20 has been developed, which had parallel plate electrodes and breech-fed propellant. It has achieved the samll impulse bit of 21 μNs with the high specific impulse of 1,000 s. However, it has been expected to increase the impulse bit, in order to apply to various missions. Therefore, in this study, the modification of thruster head configuration was conducted to increase the impulse bit, and the following two types of thruster heads were examined. One of the thruster head has parallel plate electrodes, and its propellants are fed from breech and both sides (PPT-BS150). Another thruster head is coaxial type (PPT-Co). As a result, the both thruster generated larger impulse bit than that of PPT-B20. Especially, in the case of PPT-Co, a significant increase of impulse bit was confirmed, moreover, a wide range of impulse bit from 3 μNs to 2.48 mNs (2480 μNs) was achieved by changing only the charge voltage with the same capacitance. Furthermore, the various performances (high specific impulse with small impulse bit or large impulse bit with low specific impulse) were acheived by these three thruster heads with the almost same dimensions (less than A5 paper size), small power consumption (approximately 10 W) and light structure mass (less than 2 kg).