Author Topic: Pulsed Cathodic Arc Thruster (Neumann Drive)  (Read 4450 times)

Offline Steven Pietrobon

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Pulsed Cathodic Arc Thruster (Neumann Drive)
« on: 05/13/2017 06:56 AM »
Dr. Paddy Neumann here in Adelaide has set up a company called Neumann Space to develop a new type of ion drive called Pulsed Cathodic Arc Thruster (PCAT) or Neumann Drive. This uses the basic principles of an arc welder to generate thrust from just about any metallic material, with Magnesium giving the best performance. For details on how it works, visit the website at

http://neumannspace.com/science/

The drive has the world record for the highest Isp, reaching 144 km/s, although a more typical value is 110 km/s. Power efficiency is over 90% and it operates at voltages between 80 to 250 Volts, but the current is in the kilo Amp level. Neumann Space have bought space on the Airbus Defence and Space Bartolomeo platform on the ISS in order to test their drive. Their payload is called FAST (Facility for Australian Space Testing) and is scheduled for launch late next year. It will have two opposing thrusters in order to not affect the ISS and will run off the ISS 160 V power supply.

http://www.sciencealert.com/this-physicist-just-got-the-all-clear-to-test-his-record-breaking-ion-drive-at-the-international-space-station

Check out his video showing the drive in action.

Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline gospacex

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #1 on: 05/13/2017 09:23 AM »
wow

Offline philw1776

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #2 on: 05/13/2017 02:59 PM »
Numbers for a low mass manned Mars transit

http://neumannspace.com/blog/fuel-of-the-week-molybdenum/

Glad they have rejected the abomination of using beer for propellant

http://neumannspace.com/blog/fuel-of-the-week-carbon/
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Offline Stormbringer

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #3 on: 05/13/2017 03:48 PM »
Numbers for a low mass manned Mars transit

http://neumannspace.com/blog/fuel-of-the-week-molybdenum/

Glad they have rejected the abomination of using beer for propellant

http://neumannspace.com/blog/fuel-of-the-week-carbon/

http://www.projectrho.com/public_html/rocket/enginelist.php

Quote
n The Makeshift Rocket (also known as A Bicycle Built for Brew), the old geezer cobbles together a crude rocket out of hogs-heads of pressurized beer in order to escape to an adjacent asteroid.

Quote
ed note: I asked Rob Davidoff for an estimate of the performance of beer.)

Thrust = velocity * mass_flow

Assume we model the system as the fluid starting from stagnation (V-o = 0) under pressure P_o and accelerating to a vacuum pressure P_2 = 0 at velocity v_1. We can then employ Bernoulli's equation, which says the following once we knock out some irrelevant terms:

P_o = 0.5 * rho * (V_1)2

Solve for V_1:

V_1 = sqrt( 2 * P_o / rho)

So, what's a reasonable pressure? Sheesh, I dunno. A standard fuel-driven rocket engine operates at about 35 atm for a very low-pressure combustion, let's try that. Using the density of water (1000 kg/m3), I get...84 m/s. Isp of 8.5 seconds or so. The thrust will be this times the mass flow, so 1 kg/s would give 84 Newtons.

Is this any use? It's pretty crappy, but maybe it's good enough. Say he needs, oh, 150 m/s. That's a mass ratio of 6, which isn't terrible. To lift off from an asteroid, you basically need a T/W of anything non-zero, so it's workable. Of course, keeping beer pressurized to 35 atmospheres was the starting assumption, any maybe that was a little high.

However, the big issue is the density of the beer. Substitute in an air-like gas with a density of 1.4 kg/m2 instead of 1000, and you get to an Isp of ~220s, instead of 8. That's a lot more like it.

The above cites are not my own work but the work of the folks at project rho and their contacts.

:)
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Offline CameronD

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #4 on: 05/14/2017 11:19 PM »
Glad they have rejected the abomination of using beer for propellant

http://neumannspace.com/blog/fuel-of-the-week-carbon/

Maybe just a nod to Young Einstein?  Aussie beer is pretty powerful stuff!  ;D





With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Elmar Moelzer

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #5 on: 05/15/2017 12:56 AM »
Glad they have rejected the abomination of using beer for propellant
Could finally be a use for Budweiser beer ;)

Online MATTBLAK

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #6 on: 05/15/2017 01:05 AM »
Excellent stuff. Someone give them a huge development grant!!
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Offline Katana

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #7 on: 05/18/2017 05:17 PM »
I have a collection of ~100 papers on the topic. General isp 1000+, efficiency 10%+, inferior than hall or grid ion but have potential high mass ratio (heavy metal propellant). Theoretically possible to reach ~50% prop fraction of total vehicle, and send a cubesat from LEO to mars.

However in my own experiment to replicate these results, reliable multiple ignition is painful, especially under very high vacuum (turbo molecular pumped). The arc needs to be started by solid surface discharge, and become very sensitive to insulator surface status.  If the vacuum pump is not good, starting seems to be easy (starting as glow discharge and transition to arc).

Offline Steven Pietrobon

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #8 on: 05/29/2017 12:07 PM »
Just come back from a presentation by Dr. Neumann. They are flying their FAST Bartolomeo platform in February 2019. It will be carried as an external payload, possibly on a Dragon CRS mission. Payload is 125 kg with 250 W of power and 3.75 TB/day data. Location is on the Columbus external payload attachment, with views forward, nadir and zenith. Airbus Defence and Space is charging €50,000/kg which is cheaper than what they could get with Nanoracks. To measure thrust, they are using strain gauges inside a Faraday cage to avoid interference from the engine.

They are also providing space for secondary payloads. The South Australian government is paying AU$80,000 for 1 kg and 4 L of volume. This will be used for various student experiments. They have funding from venture capital.

http://www.adelaidenow.com.au/technology/science/sa-schoolkids-given-chance-to-submit-science-projects-to-be-done-international-space-station/news-story/943dad845e91b8c424b744c8eeebe649

Katana, you need to read Dr. Neumann's thesis.

https://ses.library.usyd.edu.au/handle/2123/13810

His latest research using magnetic coils he was able to get 100 km/s Isp and 95% power efficiency using Magnesium!
« Last Edit: 05/29/2017 12:16 PM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline john smith 19

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Re: Pulsed Cathodic Arc Thruster (Neumann Drive)
« Reply #9 on: 05/29/2017 01:31 PM »
His latest research using magnetic coils he was able to get 100 km/s Isp and 95% power efficiency using Magnesium!
That's better than 10 000 secs. I imagine the fact this is designed to operate in a pulse mode can simplify the problem quite a lot. The elimination of high pressure gases Eg Xenon also simplifies handling due to safety constraints.

If the propulsion system can be suitably scaled down we really could be looking at cubesats to Mars/Venus/Mercury. Possibly bigger probes built around payload adapters to the outer planets?
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

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