Hello from Germany

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Wolfgang Bauer
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Joined: Fri Jan 04, 2019 10:15 pm
Real name: Wolfgang Bauer

Hello from Germany

Post by Wolfgang Bauer » Sat Jan 05, 2019 6:11 pm

Hello,

My name is Wolfgang Bauer from Bonn in Germany. I'm interested in space propulsion systems and during learning about electrical propulsion systems I found this very helpful forum.
Currently I have a small rotary vane pump and a self constructed aluminum chamber in a T-shape with a tube diameter of 160 mm. Unfortunately the chamber welds are still a bit leaky, why I don't get a vacuum better than 43 Micron. To learn more about plasma and the needed equipment to work with it, I'm on the way to build a demo fusor.

It is nice to meet so many open-minded interesting people. I have more confidence that one person/group here will build the first fusion reactor working break even, than ITER.

ian_krase
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Joined: Mon Nov 28, 2016 7:48 am
Real name: Ian Krase

Re: Hello from Germany

Post by ian_krase » Sat Jan 05, 2019 10:35 pm

43 micron isn't terrible for a rotary vane pump.

However, it's my understanding that Aluminium just doesn't weld gas-tight. You may be able to seal it with Loctite 290 (the green penetrating kind -- put it on the outside of the chamber where you think there's a leak and pull a vacuum.)

Wolfgang Bauer
Posts: 3
Joined: Fri Jan 04, 2019 10:15 pm
Real name: Wolfgang Bauer

Re: Hello from Germany

Post by Wolfgang Bauer » Sat Jan 05, 2019 11:26 pm

Thanks for your hint. I already closed some bigger holes I found by pressurize the chamber to about 300mbar and looked where dish liquid creates bubbles. I used UHU Plus endfest 300. Your idea using Loctite 290 seems to work better, due to the lower viscosity. I will try it next week. Maybe I will also use it inside the chamber to seal the welds there, because I think that I have created virtual leaks at some spots. (welded from the inside and outside) If I apply the Loctite immediately after flooding the chamber on a virtual leak it should still suck it in, otherwise it is not a big virtual leak.

Michael Bretti
Posts: 167
Joined: Tue Aug 01, 2017 4:58 pm
Real name: Michael Bretti

Re: Hello from Germany

Post by Michael Bretti » Sun Jan 06, 2019 2:08 am

Wolfgang Bauer,

Welcome to the forum. Like yourself, one of my main interests is electric propulsion for space applications. I don't believe there are very many others here who are working on propulsion projects, but it is still a great resource for the necessary vacuum related information you will need for such a project, as well as for general plasmas.

I have just recently completed the engineering design of my micro-propulsion testing chamber that you may be interested in looking at for reference. It is based off of standard 6" conflat hardware, with a full viewport and numerous inputs for the engine and diagnostics, and optimized for high pumping speed. You can find the full system details and specifications here: http://appliedionsystems.com/portfolio/ ... g-chamber/

Vacuum simulations using Molflow for ultimate pressure during pumpdown for various levels of chamber conditioning for the system can be found here: http://appliedionsystems.com/portfolio/ ... g-chamber/

I also wrote up a short overview post on the simulation results on the forums here as well: viewtopic.php?f=10&t=12575

My primary goal with this system is exploring the open source research and development for propulsion systems for small satellite applications such as CubeSats. I will be mainly focusing pulsed plasma thrusters, but may explore other engines down the road. However, depending on what happens with progress for my other major build, a particular type of high-power accelerator, this project may be put on hold for a while since I may need to borrow some of the propulsion chamber hardware to create a time-of-flight and diagnostic beamline for energy and current measurements of my accelerator. It depends on how I decide to prioritize my resources, and what I can obtain for either project.

Good luck with your endeavors, and feel free to ask questions! There is a huge amount of knowledge here, and chances are someone will be able to help.

Wolfgang Bauer
Posts: 3
Joined: Fri Jan 04, 2019 10:15 pm
Real name: Wolfgang Bauer

Re: Hello from Germany

Post by Wolfgang Bauer » Sun Jan 06, 2019 3:46 pm

Great! Yes, I think there are in general not a lot of people working on electric propulsion projects, yet. But the community is growing. There are already some start-ups selling systems for CubeSats. E.g. https://www.enpulsion.com/
Did you work on CubeSats before, too? I worked on the DragSail-CubeSat/Compass2, which was launched in 2017.

Michael Bretti
Posts: 167
Joined: Tue Aug 01, 2017 4:58 pm
Real name: Michael Bretti

Re: Hello from Germany

Post by Michael Bretti » Sun Jan 06, 2019 6:34 pm

Awesome! Very cool that you were involved in an official Cubesat project yourself! There is definitely a lot of start-ups popping up all over the place for space propulsion. Problem is, the technology is still absurdly expensive, and chances are many open source and small groups launching small satellites in the cubesat and picosat range can't invest that much in propulsion, especially when the propulsion modules alone could cost more than the entire satellite and mission itself.

I have never professionally worked on cubesats - this is purely just a hobby of mine (though I do work at a linear accelerator facility, so my accelerator research is both hobby and professional). There is definitely a growing community for open-source cubesat development - a bunch of work particularly from The Libre Space Foundation with their work on the UPSat and similar projects. Lots of growing info and interest in open source supporting hardware, software, and communications, but still little to nothing on open-source propulsion development. I think once the amateur community gets more involved in this particular area, there would be a lot of great developments for low cost, open-source solutions. Problem is, the barrier for entry (both cost and expertise) is still very high. However, a very simple high vacuum chamber could easily be built for the cost of a decent fusor (as demonstrated with my 6" conflat chamber), and simple propulsion like PPTs offer a lot of opportunity for incredibly low cost and open-hardware style development orders of magnitude less in cost than what can be bought commercially.

I hope I can help contribute to these areas, and maybe one day have a propulsion design of my own actually used and flown in space (though I am still a very long way from that.)

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