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back to article Plasma space-drive aces efficiency numbers: Set for ISS in 2014

Top boffins working at a NASA spinoff company are thrilled to announce that their plasma drive technology – potentially capable of revolutionising space travel beyond the Earth's atmosphere – has checked out A-OK in ground tests. The VX-200 blasting Argon at full bore in ground trials. Credit: Ad Astra Rocket Co What …

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Now if only...

we as a species could stop squabbling over petty things like whose cosmic wizard is the least silly and focus our efforts and resources we might actually stand a chance of making it out of this solar system...

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Coat

screw that

Let the space wizard worshippers stay here while us sensible humans jet off into the stars. They seem quite happy for everything to stay exactly as it is or even better - regress back to medieval times.

They hate new technology so I think they would probably be happy if we all left them to it.

Maybe we'll check in on them after a couple of hundred years if we fancy a laugh.

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Stop

Wait

Lets not fling ourselves out there until we have worked out how to live here sustainably. We should spend the effort on solving the challenges of nuclear fusion power first.

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*ding* You have discovered politics!

What the hell is this, Civilisation 4? I'm just waiting for a military advisor to turn up and recommend nuking everything!

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RE: screw that

There is always the B-Ark! ( courtesy of D. Adams )

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@ Graham Dawson

Dust off and nuke the site from orbit: it's the only way to be sure.

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do both

we could do both. we have the resources. if only we could use them properly.. for creation rather than destruction.

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Sir

I'm not very good at maths, what does a sustained 5.7N translate to in G?

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Joke

It approximates

to somewhere between 0 and sweet f*** all I think.

Whatever happened to "Give me a fulcrum, and I shall move the world."??

There was a man with vision.

Anywho, well done to the chaps.

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calculating thrust from Newtons to G

"I'm not very good at maths, what does a sustained 5.7N translate to in G?"

over 1G, for a 500g object :)

5.7 / (10 * mass in kg) = thrust in G

so less impressive for, say, several hundred tonnes :(

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title

F=ma, where 'F' is force (5.7 Newtons in this case), 'm' is the mass being accelerated and 'a' is trhe resulting acceleration.

Rearranging gives a=F/m

As an interplanetary spacecraft is likely to have a mass in the order of a few tonnes, 'a' is going to be very, very small.

The advantage of this type of engine is it can apply this tiny acceleration for days, weeks and months at a time rather than the few seconds of a more powerful but less fuel efficient 'firework' type engine.

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Boffin

conformability

Depends on the mass you want to accelerate, according to F=ma. 5.7N is the 'F', and g is the 'a', so you'll need to pick an 'm'.

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Boffin

translate to G

5.7N(force) cannot be translated to G (acceleration) without a mass component (f=ma).

the simple way to visuallise 5.7N is to imagine how much Mass it could hold against G. ie m=f/a therefore 5.7N can hold 0.581KG steady (levitate it) in 9.81m/s^2 gravity. ie this engine could hold 581grams in a hover. Hopefully you can visulise holding 581g in your hand, that is 5.7N force in earths gravity 1G = 9.81m/s^2.going further of all the items on my desk in front of me, the metal stapler is closest to 580g.

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Practical numbers

The "teach a man to fish" guys are spot on here. 5.7 newtons of force applied to a 100 ton spaceship, you're talking a 10 millionth of a g force. Paltry, but if you apply the force continuously in the right direction, VERY useful. In the ISS it would let them cheaply and effortlessly raise or lower their orbit. For long range missions, add more motors and ramp up the power - apparently the VASIMIR scales very nicely.

Best thing to happen to space science in 40 years.

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Pint

581g

Curiously enough, that is exactly the weight of a pint of beer.

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Well, you asked.

6.67E-11.

(Did you mean "g"?)

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Pedant

"Give me a place to stand, and I will move the earth" - Archimedes.

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@ Steve X

What about a pint of light ale?

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Spec

For serious travel a spaceship should accelerate half way and then decelerate all at 1 G . Travelers experience an earth like environment and they get somewhere fast.

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Vic
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Different units

> what does a sustained 5.7N translate to in G?

It doesn't. The Newton is a unit of force, "g" is a measure of acceleration.

If we were to assume a mass of one tonne for the drive unit (it was described as about the same size as a small car), we'd get an acceleration of 5.7mm/s^2, or approx 0.00058g.

Not as quick as my bike, but likely to go a bit further without refuelling...

Vic.

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Pint

Spaaace beeer!

That might explain that experiment where they want to fit a VASIMR drive on a beer can to make it go into space!

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Boffin

Depends on the mass.

Gravity is an acceleration. Newtons are a unit of force. The standard equation between them is

Force (N) = Mass (g) x Acceleration (m/s/s)

The closest relevant unit is the gram-force ((g*m)/(s*s)), which uses the Terran gravity constant (G) for acceleration. Based on calculations, 5.7N equals 581.238241397 gram-force.

As the article states and as the example illustrates, 5.7N isn't exactly a huge force, but if allowed to exert over a long period, it can still translate into a LOT of acceleration.

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Re: Pedant

It's a fucking good thing for all of us that Syracuse is obviously not the right place to stand then.....

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Boffin

Pedant #2

I don't think Archimedes was very literate in English.

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@Charles 9

Not acceleration.

Apply that small force for a long time and you get a lot of delta-V.

Rocket science is all about delta-V (Change in velocity). Acceleration is merely a means towards that - accelerate a lot for a short time, or a little for a long time.

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Yea

That solves oh so many problems. How does that work out in terms of time-to-travel to Mars?

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Happy

But surley...

“Further out from the Sun, however - towards Mars, the main Asteroid Belt and the outer planets - some other source of power would be needed…”

Just use hydrogen and anti-hydrogen from the Large Hadron Collider, just like the do on the Enterprise.

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Pint

Two things

1. It's a bit difficult to bottle anti-hydrogen, and it doesn't seem to exist very long.

2. Stop calling me shirley.

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Oh, yeah...M/AM reaction assemblies...

*pffffffffffffft*

First off, M/AM reactions emit all usable energy as photons. So this gives you two choices:

1) Capture the photons for use as electricity (our extant technology here is inefficient)

2) Use the photons to superheat a propellant, sort of like...and ion engine!

Given the mass of the equipment you'd need to create antimatter containment bottles, M/AM RA type engines wouldn't be more efficient than fission/ion engines even if you could recover 100% of the energy from the conversion of both the matter and the anti-matter. Problem is...we can't recover 100% of the usable energy from a M/AM reaction...and 50% of it escapes as neutrinos anyways!

When you figure out how to capture neutrinos and derive power from them, we'll talk. Also, you'll have solved all of humanity’s power problems until the end of time. Until then, give me a fission reactor, baby!

Hell, give me one next door to my house. Anything’s better than these toxic coal plants. We don’t get enough sunlight at my latitude for photovoltaic to be useful (if it actually is anywhere,) and windmills seem to consume more energy in their manufacture than we actually could extract from the atmosphere here. Hydro and fission, baby: only way to go!

And in space, the hydro is all frozen…

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"Ad Astra"

"To the stars"

I hope they didn't have to pay the strategy boutique too much for that name.

(Flame icon for plasma exhaust)

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strategy boutique? what strategy boutique?

Actually given that one of the founders of Ad Astra is a former astronaut -- and a real rocket scientist, to boot -- I wouldn't be surprised if they came up with that one themselves, without the aid of whale songs or burning sage.

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Let's hope it does not become the full phrase

Well, good luck to them and let's hope it does not become "Per aspera ad astra".

Flame icon for all those interested in a flaming chemical exhaust whose party this will spoil.

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Joke

Re: Ad Astra

I think Vauxhall have been ahead of the game for years with the VX 220!

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I prefer

Ex astris, scientia.

But then, I'm a sucker for nostalgia...

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Please!

I would *love* to work for a company called 'Ad Astra Rocket Company'.

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A real step

In space propulsion - good work!

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Happy

At last-

a space engine that *looks* like a space engine!

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Boffin

In space...

..no one can hear you scream. So why are the radiators(?) on that uber-rocket thing streamlined?

Grips my tits when spacecraft are made to look and manoeuvre like aircraft...

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Two reasons

To look cool and to look f@&king awesome!!

That's all folks!

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Yeah but...

The Borg have shown us cube-shaped spaceships don't look have half as good as any of the gratuitously aerodynamically styled stuff

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@ JonW

"..no one can hear you scream. So why are the radiators(?) on that uber-rocket thing streamlined?

Grips my tits when spacecraft are made to look and manoeuvre like aircraft..."

Presumably because they need to be transported to space through the earths atmosphere before their interstellar jaunt. I agree, once up there, a ruddy great cube (ala Borg) would be fine and dandy (barring the sparse hydrogen getting draggy when travelling at silly speed*), just getting it there would be an arse

(*this thing seems fast, but I don't think it would be fast enough for this to be an actual issue)

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Not streamlined

The radiators are hiding from the radiation from the nuclear reactor (the grey tube with a x-on the end). It's more mass efficient to only make a small rad shield so the rest of the craft has to hide in the cone that's shielded.

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Re: In space...

Try this for not aeroplane-like:

http://www1.eveinfo.com/img/ids/512_512/49.jpg

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Nuclear

The main concern about nuclear is the potential damage/contamination caused by a failed launch of a fuelled reactor. Can't they launch the reactor empty, and then send the fuel up in a number of extra-tough containers, for robot (or ISS) assembly in orbit?

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Boffin

Re: Nuclear

When Lewis mentions "nuclear", he frequently deliberately omits the distinction between nuclear fission reactor technology and radioisotope generators, perhaps because he's riding some nuclear high horse or other. That various missions might use the latter technology is nothing new - I guess that's what the Mars Rover references are suggesting - but although the former technology is also nothing new, it's also controversial for the reasons you give and others: look up RORSAT on Wikipedia, for instance.

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Go

Launch empty and fuel in orbit

Yes, that would be the way to go. Also un-used enriched Uranium fuel rods aren't a serious hazard. Enriched Uranium is only a few times more radioactive than natural Uranium, and Uranium oxide pellets in Zirconium tubes are pretty robust. We'll be OK just as long as a well-used reactor never re-enters, with all its accumulated fission by-products. Dump used fuel rods into the Sun?

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What is really needed..

Is a very long piece of string that you can hook your ground-based item of equipment to.

The other end of the string is held beyond geosynchronous orbit and is used like a giant space elevator to move things into orbit.

Can we have one of those as well please?

ttfn

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More likely because...

it matters little. A RTG usually uses plutonium so a uranium-fueled reactor is actually safer to launch. But this cuts no ice with Greenpeace etc.

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Anonymous Coward

fuel rods to the sun

actually i am curious about this, i have been for years, obviously blasting used fuel rods in to space on chemical rockets isnt a smart idea given that the rockets are essentially a barely contained explotion that quite often do blow up but in all seariousness assuming we could get that stuff in to space what would be the effect of blasting it in to the sun, it wouldnt get anywhere near the sun before burning up and everything around there is somewhat hazardus to us anyway.

before the eco folk go on about not dumping our waste in to some other backyard which i would agree with, just think for a second what would actually be left? i dont know the answer so im just asking the question

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fuel rods to the sun

Assuming we could come up with a safe way of getting the rods up there then you're quite correct. There is more radioactive material contained in (and radiation spewing out of) the sun than all the nukes we've ever made or could ever make.

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