- 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.
The AIS-gPPT3-1C Series Integrated Propulsion Module represents the latest 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 the first available propulsion system specifically designed to operate with the incredibly stringent power and space restrictions for PocketQubes.
The thruster module features the newly designed AIS-gPPT3-1C thrusters fully integrated with a custom power supply board. Mounting hole configuration can easily be adjusted based on PQ mounting standards and individual needs. The board features a compact space-heritage high voltage EMCO Q Series DC-DC converter. Peak power draw is around 825 mW, with an average power draw of 163 mW for the entire thruster module, providing up to 1000V for the main capacitor bank during nominal 0.33Hz operation. A high voltage trigger coil is used to provide 5kV 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 off of standard 3.3V PQ main power, with max input voltage of up to 5V. High voltage enable is controlled via high side load switch, driven from standard PQ logic output to directly turn on and off the high voltage supply as needed. For ignition, standard PQ logic pulses can be used to switch the sensitive-gate thyristor, set to the desired firing rate, after high voltage has been enabled. Very high value, high voltage pulse-withstanding dividers are used on the board to provide voltage feedback for the main bank and ignition bank. With this simple feature, the 1000V main bank and 300V ignition bank voltages are brought down to 2V for direct analog reading from a PocketQube main controller with analog input capabilities. By verifying both ignition and main voltages drop briefly to 0V 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 present, the AIS-gPPT3-1C Series Propulsion Module is the first official, open-source, ultra low-cost propulsion module specifically optimized for PocketQubes, and may be the lowest-cost, smallest form-factor, completely integrated propulsion system available on the market to date.
- Thruster Type: AIS-gPPT3-1C Micro Sub-Joule Pulsed Plasma Thruster
- Fuel: Teflon, Ultem, PEEK (optimal fuel TBD)
- Max Power Draw: 825 mW
- Average Power Draw (0.33Hz): 163 mW
- Primary Capacitor Bank: 0.2 uF
- Primary Bank Working Voltage: 1kV
- Thruster Energy: 0.09J
- Ignition Voltage: 5kV min
- Pulse Repetition Rate: 0.33-0.25 Hz Nominal
- Size: 40mm x 38mm x 24mm
- Total Thruster Mass (Teflon): 34 grams
- Usable Propellant Mass (Teflon): 62-99 milligrams (estimate)
- Vacuum Levels Tested: <1×10^-5 Torr
- Impulse Bit: 0.65uNs
- Lifetime to Date: 150 shots
- Total Impulse: TBD
- Thrust (0.33Hz): 0.22uN
- Current Testing Level: Lifetime Testing
- Completed Testing Level: Atmospheric Igniter Test, High Vacuum Ignition Test, Impulse-Bit Test
- Status: ACTIVE
BILL OF MATERIALS
ENGINEERING TEST REPORTS