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Launch a Water-Propelled Satellite into Deep Space

kickstarter.com

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Re: Launch a Water-Propelled Satellite into Deep Space

#41

Post by troymc »

iharris wrote: post #7
ThomPete wrote: post #6

Off-topic I have seen even Nasa uses Spaaaaaace as a word. Anyone have an explanation?

Portal 2 reference: http://www.youtube.com/watch?v=xeKMS62GrTI Edit: It's clear that someone in NASA is a Portal fan - they sent a laser-etched image of Wheatley up with an HTV-3 resupply craft: http://www.escapistmagazine.com/news/view/118637-NASA-Sends-...

I'm not sure, but I suspect that the Portal 2 reference might itself be a reference to the recurring Muppet Show sketch "Pigs in Space" (pronounced Piiigs innn Spaaace).

https://www.youtube.com/watch?v=tYjbkRktqIE

Re: Launch a Water-Propelled Satellite into Deep Space

#42

Post by Pinckney »

outworlder wrote: post #24

I am unsure what is the relevance of water in this project. It is not like the noble gases used in other engines (including ion) are difficult to find or too expensive. Unless there's the long-term goal of collecting water in order to 'refuel' the craft. Which is unlikely, as they are too tiny to afford thee extra machinery. I'm thinking it's just a matter of reducing for the 'fuel tanks'.

Xenon is actually pretty expensive.

http://boards.straightdope.com/sdmb/showthread.php?t=581982

Re: Launch a Water-Propelled Satellite into Deep Space

#43

Post by robotresearcher »

sherjilozair wrote: post #11

I don't understand. $50K being asked by professors and PhD students? They certainly enjoy funds orders of magnitude more. $50K is like two YC startups' seed money. Why do they want it? Can't they self-fund it? Or do they just want other people to share the glory? Isn't the equipment shown in the video worth as much, or probably more?

Why do people think funding science is easy?

"They certainly enjoy funds orders of magnitude more."

Certainly? If they had the money already they wouldn't be asking for it. Perhaps they have had this proposal declined once or twice by the agencies. Science is very competitive and the majority of proposals are not successful: 10% acceptance rates are not unusual. It's also highly winner-take-all since winning funding tends to generate output which tends to attract more funding.

"$50K is like two YC startups' seed money."

Which is loaned in expectation of a return. Science funding is a gift in the hope of a long term strategic advantage. The government doesn't just hand out $50K to Prof. Doe on request. Besides, $50K would barely support one PhD student-year with 50% overhead and tuition.

Researcher profs spend a large proportion of their time on grant writing and only the best are successful, and while it does come in large chunks when it comes (in the US), the expected value of each application is not high. It's much easier for the currently in-vogue fields than others. It's also hugely easier if you have a little industrial funding, as there are many matching programs. This means getting the attention of the industrial players, if there are any in your field. Very time consuming!

Re: Launch a Water-Propelled Satellite into Deep Space

#44

Post by tocomment »

InclinedPlane wrote: post #28
tocomment wrote: post #26

Would something like this be able to work within the atmosphere?

In a word: no. It generates a very minute amount of thrust. That's ok in the freefall of space because acceleration running 24/7 adds up fairly quickly. But these thrusters won't have a thrust to weight ratio higher than 1 so they can't feasibly be used for in atmospheric flight.

But couldn't a version be built on the same principles that has higher thrust?

Re: Launch a Water-Propelled Satellite into Deep Space

#45

Post by robotresearcher »

notahacker wrote: post #15
sherjilozair wrote: post #11

I don't understand. $50K being asked by professors and PhD students? They certainly enjoy funds orders of magnitude more. $50K is like two YC startups' seed money. Why do they want it? Can't they self-fund it? Or do they just want other people to share the glory? Isn't the equipment shown in the video worth as much, or probably more?

$50k is also a rounding error in the budgets of national space agencies and private sector players in the space industry, many of whom might be interested in a magical and revolutionary propulsion technology that could - if possible to extend to larger satellites - dramatically increase the design life of existing satellites and reduce the risk of failing to attain the desired orbit.

The piles of money at NASA, DOE, etc. are already allocated to things. They employ a lot of people on strategic projects. There is extreme competition for the small fraction that is available for new bids at any one time.

Re: Launch a Water-Propelled Satellite into Deep Space

#46

Post by avmich »

tocomment wrote: post #44
InclinedPlane wrote: post #28

Earlier quoted context omitted.

In a word: no. It generates a very minute amount of thrust. That's ok in the freefall of space because acceleration running 24/7 adds up fairly quickly. But these thrusters won't have a thrust to weight ratio higher than 1 so they can't feasibly be used for in atmospheric flight.

But couldn't a version be built on the same principles that has higher thrust?

It will require correspondingly more power, and then the mass of power supply will be a problem.

Re: Launch a Water-Propelled Satellite into Deep Space

#47

Post by nhangen »

sliverstorm wrote: post #23
maxerickson wrote: post #20

Earlier quoted context omitted.

What do you mean by deliverable? "There will be a camera for science" is an end result.

He means a link between, you donate, they make product. You donate, they achieve X with your money. This one reads more like, "We have vague plans and lots of money but we need more, please contribute to our slush fund". As best I can tell, the direct impact of the kickstarter funds will be paying for a camera to put on a launch vehicle to watch the CAT engine, but it's not very clear.

You said it better than I could. Exactly this.

Re: Launch a Water-Propelled Satellite into Deep Space

#48

Post by Pinckney »

tocomment wrote: post #44
InclinedPlane wrote: post #28

Earlier quoted context omitted.

In a word: no. It generates a very minute amount of thrust. That's ok in the freefall of space because acceleration running 24/7 adds up fairly quickly. But these thrusters won't have a thrust to weight ratio higher than 1 so they can't feasibly be used for in atmospheric flight.

But couldn't a version be built on the same principles that has higher thrust?

Ion thrusters have atrocious thrust to weight ratios. You can slap more ion thrusters on, but that adds mass linearly. You can't scale up voltage much, or you get current arcing across the acceleration region, and you can't add more ions, because they'll interfere with each other. As far as I'm aware, there aren't any designs that have thrust-weight ratios anywhere near 1.

(For perspective on just how much this would need to scale up, the CAT thruster developes 2mN thrust [0.00045 lbf] on a spacecraft that weighs 2.5kg [5lbs] without fuel.)

In any case, if you're flying in atmosphere, you can probably extract your propellant directly (or just use propellers). The whole point of ion engines is that they're fantastically efficient. This is important when you need to carry all of your reaction mass along with you (and your mass ratio scales up exponentially as a function of delta-V), but not important when you're flying through atmosphere (and surrounded by reaction mass).

Re: Launch a Water-Propelled Satellite into Deep Space

#49

Post by guiambros »

Wingman4l7 wrote: post #36
noonespecial wrote: post #3

I'd just like to point out that their first kickstarter didn't make even half its goal. We all talk about how we wish more money was devoted to research like this. Skip your latte today and toss them a fiver.

True, but their original goal was 4x this amount.

I just attended a meet-up this evening with Slava Rubin, Indiegogo's CEO, and that was one of the topics he covered during his talk. The psychology of crowdsourced projects is fascinating.

Basically the analogy is that if you want to raise 100, you set your goal to 50, and will probably end up with 120. Now if you set your goal to 100, you may end up with 20 and a failed campaign. Same project, same pitch, same perks.

Of course this is not exact science, but you got the idea. The special advice is to figure out the number that you need (versus what you want), and make sure you can cross the 1/3 of the funding early on.

Lots of things come into play: initial inertia, exposure, acceleration as you get closer to your goal, resistance around 1/3, etc.

Re: Launch a Water-Propelled Satellite into Deep Space

#50

Post by noonespecial »

guiambros wrote: post #49
Wingman4l7 wrote: post #36

Earlier quoted context omitted.

True, but their original goal was 4x this amount.

I just attended a meet-up this evening with Slava Rubin, Indiegogo's CEO, and that was one of the topics he covered during his talk. The psychology of crowdsourced projects is fascinating. Basically the analogy is that if you want to raise 100, you set your goal to 50, and will probably end up with 120. Now if you set your goal to 100, you may end up with 20 and a failed campaign. Same project, same pitch, same perks…

"People only back winners." If people think that there's no way they'll ever reach that ambitious goal, they won't contribute, so there will be no way they'll ever reach that ambitious goal.
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