

Plasma Jet Electric Thrusters for Spacecraft - iamwil
http://www.kickstarter.com/projects/2027072188/plasma-jet-electric-thrusters-for-spacecraft

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paulsutter
I'm thrilled to see this project. Yes, $69K is clearly much less than they
have invested to date. This Kickstarter is likely a PR platform for them, and
a smart one.

I'm excited because it shows that more individuals are willing to take on far-
reaching projects rather than build another mobile picture app. I hope some
deep pocketed investors vet them and get them the resources they need.

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dchichkov
Wow. Check out the updates page of that project:
[http://www.kickstarter.com/projects/2027072188/plasma-jet-
el...](http://www.kickstarter.com/projects/2027072188/plasma-jet-electric-
thrusters-for-spacecraft/posts)

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damncabbage
As much as I cringed through the video, I think the style really works for
them. :)

This is the sort of thing I love to see on Kickstarter. Best of luck!

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redthrowaway
I know it may not be the best sales pitch, but I love how incredibly nerdy and
low-budget the video is. It's a refreshing break from the hyper-polished,
artsy videos we tend to see on kickstarter. It's just four nerds looking for
funding for something nerds think is awesome.

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InclinedPlane
Here's my quick sale for these guys, which I've posted elsewhere as well when
this comes up.

First, what is this? It's a pulsed plasma thruster, which is basically just a
railgun that shoots puffs of ionized gas (plasma) instead of metal slugs.

Second, what's so great about it? Well, electric propulsion is a fantastic way
to get around in space (once you are in Earth's orbit or above) because it's
so efficient. The rocket equation is brutal, it imposes an exponential fuel
burden based on the ratio of how fast you want to go (delta V) to how fast the
exhaust of your rocket is (exhaust velocity). Unfortunately, a lot of missions
have delta V requirements that are on the scale of or significantly greater
than the exhaust velocity of chemical rockets (around 3-4 km/s), which means
that we'll always be dealing with rockets that are mostly fuel and even then
can only just barely get us to our destination. Electric propulsion systems,
such as ion engines, make it possible to have vastly higher exhaust velocities
(e.g. 30 km/s), which vastly improves the efficiency of the rockets by an
inordinate amount. For example, using a chemical rocket to go from Earth to
Mars would require at least 180% of the dry weight of the rocket and payload
being used up as fuel, whereas an ion engine could do the same job while using
about 1/12th as much fuel.

The down sides of existing forms of electric propulsion are fairly severe
though. They generate very little thrust and so must run for a long time to be
useful. For example, the Dawn spacecraft will only accumulate about 1 km/s of
delta V every 6 months. This means that some missions are unsuitable for
electric propulsion, especially manned missions (where travel time is more
critical). However, these pulsed plasma thrusters could potentially generate
around one to two orders of magnitude more thrust for the same size of engine,
making them much more suitable for high-delta-v missions or even use with
manned spacecraft.

Additionally, ion engines use a grid that is exposed to the flow of the ions
that become the exhaust, and that grid can often become fouled or eroded by
the flow, limiting the effective service life of the thruster, whereas pulsed
plasma thrusters have much different limits.

Third, why hasn't NASA already worked on this technology? Well, partly because
ion engines have seemed to some like a more worthwhile technology. However,
ion engines have received a lot of commercial development and are fairly
commonly used on geostationary satellites, and there the low thrust is not a
problem. So partly it's also that NASA has mostly just made use of otherwise
well-proven, off the shelf technologies.

Overall the project is probably worth at least a few bucks if you have any
interesting in advancing the technology of spaceflight.

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tocomment
How does this compare to VASMIR? Is there a chance NASA would start using
this?

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InclinedPlane
It's infinitely more practical than VASIMR, which has tremendous minimum
energy requirements and fairly poor overall thrust/weight ratios once that is
taken into account. VASIMR is only practical if you have hundreds of kilowatts
to work with, which means you need a space-based fission reactor, which
currently is not in production anywhere in the world at present.

These pulsed plasma thrusters have very much better thrust to weight ratios
and scale down much better. They are a comparably small device whereas VASIMR
requires large and complex systems of magnets and so forth. It would be easy
to run them off of solar power, for example.

If their estimates hold up once they have built their prototype thruster and
if they are able to develop it into a commercial enterprise (or license the
technology) then NASA would certainly use them given the chance.

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pkapur86
The day is not far when the next CERN is funded on kickstarter!:P

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maeon3
I like to help people working on projects like these, not only because it
could do what they think it will do, but because in playing around with
unexplored regions of physics, they may accidentally stumble into something
far more than they could have imagined.

Kind of like the story of Alexander Fleming where he was trying to find some
enzymes to kill bacteria, and accidentally figured out that mold in his sink
kills the bacteria, and invents penicillin.

We need something like that, again, for electric engines.

[http://www.essortment.com/alexander-fleming-discovery-
penici...](http://www.essortment.com/alexander-fleming-discovery-
penicillin-40564.html)

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rorrr
1) Your funding goal is ridiculous. $69K, really? Four engineers could not
pitch in to get that much?

2) Your highest investment pledge ($10k or more) is an insult to the investor.
They will essentially pay for 1/7th of your company, while getting no % of
your company in return.

3) Your presentation is OK, but you really need to put microphones closer to
the speaker.

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shabble
_> Your highest investment pledge ($10k or more) is an insult to the investor.
They will essentially pay for 1/7th of your company, while getting no % of
your company in return._

There's absolutely no way that this 70k is the value of the company. Their
existing plant is probably worth 5-10x that even at bankruptcy auction prices.

My understanding (although I haven't looked in too much depth) is that they're
an established company doing work in one area (fabrication for plasma/fusion
research) who have come up with a novel use for some of their tech/skills, but
can't really justify the cost/opportunity cost of this particular app.

So they're asking for essentially donations to develop the thing, in exchange
for very low-cost returns plus a final project demo. It's really the patronage
model applied to research.

Also, for 10k you do get naming rights to the tech, and some advertising
opportunity during the final tech demo, which is probably valuable to some
companies, especially given the audience targeting this thing is likely to
attract.

Pitching for equity investment in the company requires a much more substantial
business plan ("Make cool thing, produce internet videos & some research data"
isn't really going to work), and it may just be that they don't see the value
right now in doing the work necessary to attract those sorts of investors.

I imagine if this test is successful and there is any hint of actual
commercial prospects from existing satellite/space manufacturers, they'd take
a more conventional route to funding to get the thing built.

For "Hey, wouldn't it be cool if...?" studies, I think this is a good way to
go about it, and $40k of people already agree.

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vixen99
"Thuster"?

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InclinedPlane
This is unhelpful, say what you mean.

