The AIS-gPPT3-1C Series Integrated Propulsion Module represents the first advance of open-source, low-cost micro-propulsion at Applied Ion Systems, and a first of its kind for the propulsion field. The module is specifically designed to operate with the incredibly stringent power and space restrictions for PocketQubes and Cubesats, and serves as an ultra-low cost, low-power, and simple to use demonstration propulsion module for both ground as well as orbital testing. The AIS-gPPT3-1C Series Module allows any PocketQube and Cubesat team to explore the use and control of electric propulsion, paving the way for more advanced system use and integration for future missions. Currently, two modules have been integrated aboard the AMSAT-Spain GENESIS N and L PocketQubes, launching in December 2020.
The thruster module features the AIS-gPPT3-1C thruster head fully integrated with a custom power supply board. The board features a compact space-heritage high voltage EMCO Q Series DC-DC converter. Peak power draw is around 280mW, providing up to 1500V for the main capacitor bank during nominal 0.25Hz operation. A high voltage trigger coil is used to provide -10kV trigger pulses for ignition of the thruster, which is also powered from the main high voltage supply.
The power supply is designed to be directly driven from 4VDC. High voltage enable is controlled via high side load switch, driven from standard logic output to directly turn on and off the high voltage supply as needed. For ignition, logic pulses can be used to switch the sensitive-gate thyristor, set to the desired firing rate, after high voltage has been enabled. High value, high voltage rated pulse-withstanding dividers are used on the board to provide voltage feedback for the main bank and ignition bank. By verifying both ignition and main voltages drop briefly after the trigger command, successful firing can be confirmed in space, as well as missed pulse tracking and overall thruster lifetime tracking by counting total number of successful ignitions. In addition, bank voltages can be verified they are at correct operating levels during nominal use, and pulse energies per shot can even be tracked and recorded as well.
The thruster module features an incredibly compact form factor, with a board footprint of 40mm x 38mm x 24mm. With an allowed maximum of 7mm protrusion from the PocketQube outer frame dimensions, the total inner depth is further reduced to 17mm depth (0.34P). With the low power requirements and small form factor, the propulsion module can be used on satellites down to 1P size PocketQube standards.
At only $2500, the AIS-gPPT3-1C is the lowest cost and most compact completely integrated micro plasma propulsion system on the market, aimed at providing any nanosat team the ability to begin control and testing of electric propulsion aboard their satellite.
- Price: $2500
- Thruster Type: AIS-gPPT3-1C Micro Pulsed Plasma Thruster
- Fuel: Teflon
- Max Power Draw: 280 mW
- Primary Capacitor Bank: 0.136 uF
- Primary Bank Working Voltage: 1.5kV
- Input Voltage: 4V
- Thruster Energy: 0.15J
- Ignition Voltage: –10kV
- Pulse Repetition Rate: 0.25 Hz Nominal
- Size: 40mm x 38mm x 24mm
- Total Thruster Mass (Teflon): 34 grams
- Usable Propellant Mass (Teflon): 50-99 milligrams (estimate)
- Vacuum Levels Tested: <8×10^-7 Torr
- Impulse Bit: 0.65uNs
- Rated # of Shots: 1000 (1400 MAX)
- Total Impulse: 650uNs
- Thrust: 0.22uN
- Test Readiness Level (TRL): 6
- # of Systems Delivered to Date: 3
- Status: ACTIVE – AVAILABLE FOR PURCHASE
ENGINEERING TEST REPORTS
VACUUM TEST PLATFORM
- 07/25/2019 – Preliminary simulations for propulsion module electronics charging characteristics completed.
- 07/26/2019 – Official CAD concept model for the AIS-gPPT3-1C Series Integrated Propulsion Module revealed on social media.
- 07/29/2019 – Official CAD concept model for the AIS-gPPT3-1C Series Integrated Propulsion Module with example adapter plate for PocketQube integration revealed on social media.
- 07/30/2019 – Official CAD concept model of the AIS-gPPT3-1C Series Integrated Propulsion Module mounted in a standard 1P PocketQube frame revealed on social media.
- 07/31/2019 – Concept model of test PocketQube frame with mounted propulsion module in the Micro Propulsion Test Chamber for advanced integrated system testing revealed.
- 08/01/2019 – Design decision to switch to the EMCO Q-series 0.5W supply for the 1P module.
- 08/02/2019 – Preliminary performance comparison with the STRaND-1 Cubesat, which also uses low energy PPTs and a series of x8 EMCO Q-series supplies for power.
- 08/05/2019 – Circuit simulation completed comparing performance between the full 5V input for the Q15-5 supply and under-driving the Q20-5 supply directly with 3.3V. Average and peak power for a 1/3Hz firing rate was determined. Based on compatibility and expected performance trade-offs, the Q20-5 supply was selected for the 1P module.
- 08/09/2019 – Final PCB layout for V1 of the AIS-gPPT3-1C Series Integrated Propulsion Module for 1P PocketQubes revealed on social media.
- 08/16/2019 – V1 boards arrive for thruster module from OshPark.
- 08/17/2019 – Components soldered to prototype V1 board for initial atmospheric testing.
- 08/19/2019 – First major milestone achieved – load switch, charging supply, and igniter tested and verified operational. No arcing on board, validating component spacing for high voltage.
- 08/20/2019 – V2 board upgrade officially revealed, including direct 3.3V triggering of the thyristor, as well as voltage monitoring for the main capacitor bank and igniter bank.
- 08/21/2019 – V1 prototype board ignition performance improved by replacing 0.047uF capacitor with 0.1uF capacitor, and increasing R2 charging resistor from 6M to 7.5M to increase charging voltage from 258V to 289V. Noticeable improvement in arc strength and voltage. Comfortable arcing in air at 5kV, and rep rates up to 2Hz verified at lower output voltage.
- 08/28/2019 – Preliminary assembly of the full integrated propulsion module with new AIS-gPPT3-1C-T Series Teflon-fueled thruster.
- 09/02/2019 – First reveal of the completed AIS-gPPT3-1C-T series Teflon-fueled thruster.
- 09/03/2019 – AIS-gPPT3-1C-T mounted in vacuum chamber for first high vacuum ignition test.
- 09/06/2019 – AIS-gPPT3-1C-T passed first controlled ignition test at high vacuum! Most significant milestone achievement to date for Applied Ion Systems!
- 09/13/2019 – AIS-gPPT3-1C-T passed first impulse bit testing, averaging around 0.65uNs. After a total logged 130 shots, main bank cap failed. New capacitor and V3 design in the works.
- 09/16/2019 – V3 board design finalized and sent to OshPark for manufacturing.
- 09/26/2019 – V3 module assembled for testing.
- 09/30/2019 – First lifetime test of the V3 thruster module. Catastrophic failure of primary bank due to overdriven conditions.
- 10/03/2019 – Second lifetime test of the V3 thruster module. Reached a total of 1232 shots during the test at 4V input before primary bank capacitor failed.
- 10/08/2019 – First two V3 flight modules assembled for Fossa Systems mission.
- 02/06/2020 – AIS-gPPT3-1C successfully integrated to AMSAT-Spain GENESIS PocketQubes
- 02/14/2020 – AIS-gPPT3-1C passed vibration testing aboard AMSAT-Spain GENESIS PocketQubes
- 06/20/2020 – AIS-GPPT3-1C INTEGRATED PROPULSION MODULE DESIGN FILES OFFICIALLY RELEASED UNDER CERN-OHL-S V2
- 12/06/2020 – Original gPPT3 revived and run for second official lifetime test.
- 12/13/2020 – gPPT3 design updated with modified fuel bore, insulator, and cathode pin dimensions to improve system reliability.