Applied Ion Systems

Applied Ion Systems Patreon is now officially LIVE! Are you a space enthusiast who would like to contribute directly to development of advanced EP from the only official open source electric propulsion program out there? Let's pioneer the field together! patreon.com/appliedionsyst…

@BreakingTaps Actually yes! The @theflametrench is a great one with lots of active cubesat developers. I have been a part of the discord myself for quite a while.

Are there any cubesat discord/slack/IRC chats around? Asking for a friend 😇

@alder_riley @BreakingTaps I think this was a really cool effort! I was actually in communication with @BreakingTaps answering some questions and chatting about propulsion with him during some of his development. FEEP has its challenges, and I'm glad to see some verified measured stable beam by the end!

@BreakingTaps @Applied_Ion thoughts?

I made a liquid metal ion thruster so you don't have to ☺️ (it was very difficult 😩)

@BreakingTaps @pakhm20 However, you could do an end hall style thruster with a tungsten filament relatively easily (assuming you have gas flow). It's never really used for satellites, (mainly as an ion source in manufacturing), but the fundamentals are the same as other hall thruster styles.

@BreakingTaps @pakhm20 Gas delivery is a big one. Gridded ion is probably the harder one since you not only need a neutralizer but an extra ionizer inside the discharge chamber. Also they are much more finicky at the small scale and low power, and work more stably with larger/bigger systems.

@BreakingTaps Very excited to see this! Just finished watching it myself, really fantastic job! I think it was a really awesome overview of the technology and FEEP thruster field, and most importantly, shows just how grueling development can be. But, persistence pays off in the end! Congrats!

Second post with the link because the algo is dumb youtube.com/watch?v=dfYSBl…

@BreakingTaps @pakhm20 Actually in terms of DIY, hall and gridded ion would actually be more complicated. I would suggest plasma thrusters instead to get started. PPTs (fueled by teflon) and VATs (solid metal like titanium or bismuth) are extremely easy to build, and can even fire in much worse vacuum

@pakhm20 I think other types (gas hall effect or gridded ion) are probably more practical. Higher thrust, efficient, robust, etc My understanding is that the market is very saturated though, and not many spacecraft need extensive maneuvering. So probably not a great commercial venture

@BreakingTaps Congratulations and awesome work! It is absolute hell for sure, just endless iteration after iteration, but if you stick with it you will eventually succeed. Next step is to measure beam current (which will definitively show it is accelerating ions)!

TODAY WAS THE DAY! 🥳 Such an adorable little plasma plume too 🥺

@BreakingTaps Nice job! That tiny little dot of purplish glow is exactly what you are aiming for! No breakdowns or arcing, just a stable glow of emission. As your beam current increases, it will get brighter. With a faraday cup you should be able to confirm beam. Just gotta keep going!

Is this... hope? 🥺 Simplified to one emitter (cheers @Applied_Ion for the suggestion) and ultrasharp Not amazing, but a wee little plasma spot and a gradual buildup of sputtered gallium on the surface. Obviously going the wrong direction but first sign of real progress!

@BreakingTaps Yeah nylon hardware doesn't like vacuum and high voltage together lol. Nylon outgasses a ton and is very hydroscopic, so it makes for a really poor insulator for high voltage in vacuum. I have always used PEEK bolts from McMaster-Carr, which have never given me any issues.

Nylon screws only do this when they are very happy 😊

@BreakingTaps @AndrewA2061 Another major issue with liquid metals and glass is that when the metal (gallium, indium, etc) solidifies, whether on the surface or wetted in the pores itself, the glass could potentially crack and shatter.

@AndrewA2061 @Applied_Ion I think any metal can work (in theory), but most metals aren't liquid at reasonable temperatures. And many low-melting metals have high vapor pressure and outgas a lot (anything with zinc, etc) @Applied_Ion was playing with ionic liquids which is an alternate route to metals

I often do fast "exploratory" projects to see if it's viable for a video. Scoped to a few days, bashed together from stuff in the shop Often they fail miserably and get shelved. But sometimes it works out! This week's test: a metal field-emission electric propulsion prototype

@BreakingTaps @lougrims Stainless steel should probably work if you can wet it and get sharp enough points, I think I've seen people use it before. I think tungsten is definitely preferred both for longevity as well as its ability to be easily sharpened to extreme levels with electrochemical etching.

@Applied_Ion @lougrims Is tungsten just used for corrosion resistance? I.e. would stainless work for a shorter duration demo? Seems like it wets out most metals with the right coercion?

@lougrims @BreakingTaps Tungsten micro needles should definitely work, and they are quite cheap and readily available. I bought a few packs of them myself for experiments with galinstan fuel but never got around to it.

@BreakingTaps You should try tungsten wire (etched to a point and externally wetted) or micro needles. People have had some success with that and I think you have the equipment.

@BreakingTaps Also, electrospray systems need to be slowly conditioned at first. This means bringing the voltage up very slowly and monitoring beam current. Over time, as discharges stabilize and you condition emission edges at high field gradients, you can increase voltage and extracted beam.

@BreakingTaps Awesome to see you attempting this too! Electrospray was by far the hardest thruster system for me to get working. A few major tips I found: completely degas the tips/fuel in high vacuum for a number of hours prior to firing, chamfer edges on grid holes, electropolish the grid.

@BreakingTaps @AndrewA2061 Yeah, typically for liquid metal electrospray you need to use a porous metal emitter like sintered tungsten needles, which you have to also vacuum heat to burn off oxides to allow for wetting. It could wet the porous glass, but that would definitely have its challenges.

@AndrewA2061 CNC milling! The emitters are glass frit similar to what I did for @Applied_Ion here: x.com/BreakingTaps/s… Convincing the gallium to wet-out and infiltrate the frit is _really_ challenging though, so evaluating alternate options.

@lougrims Wow fantastic news, that is super exciting to hear! Congratulations, and I am excited to hear about what new developments you work on there in the future!

Big personal new, I am moving to New Zealand in about a month! I will be joining Rocket Lab to start development of plasma propulsion systems there. It's definitely a huge change but super exciting. Also if there is anyone here in the Auckland area please let me know!

@jurajko15 @lougrims Actually, my very first tests with Adamantane was utilizing a simple DC discharge with sublimated fuel at a few watts total power. I published these results back in 2021 (AIS-TR-22/23/24/25) as well as the glow discharge cathode and Hall thruster tests: appliedionsystems.com/reports/

@jurajko15 @lougrims I still believe Adamantane is a viable propellant, and has many benefits over its more popular cousin iodine (hence why I am still supporting my SWAG thrusters/tanks). That being said, there are a lot of quirks to it where you need to prioritize fuel simplicity vs performance.

.@Applied_Ion somebody picked up on your adamantane idea!