I finally started soldering up and testing the new AIS-gPPT3-1C thruster learning kit prototype. Still needs some tweaks but it’s getting there! In the video I am running the actual gPPT3 test control code, monitoring one of the output channels.
For the kit I found a purple/blue LED with a nice color similarity to the plasma plume. I’ll still need to adjust the timing, probably need to have it pulse a bit faster per shot. I might also include an onboard indicator LED to show when the system is armed and enabled for firing.
The output signals are more idealized from the real thing (thyristor dumping onboard capacitors into a resistive load rather than the pulse transformer or the actual plasma discharge itself), but it is meant more to demonstrate the basic principles of operation of the thruster. Controls, size, mounting, and interface however are the same as the real thruster. In this example, the board is controlled via Arduino, with 5V in, active low enable, and several hundred ms pulse trigger command for firing the thruster, which only fires the LED when armed, at the nominal operating repetition rate of 1/3Hz.
I haven’t ordered a 3D printed gPPT3 thruster stack to bolt onto the board over the LED yet for the full test fit, but I’ll probably do that soon, in addition to some housings for the new ePPT1 thruster I’m working on, as well as the ILIS1 learning kit that is underway. Once I finalize the design and work out the bugs, the kit files will also be released open source like the thruster, and kits will also eventually be available on the AIS website.
While it’s a very simple circuit, it can give anyone the opportunity to start getting involved in EP, exploring the control and basic principles of actual electric propulsion systems that have been designed, tested, and even flown in space!