New anti-matter engine ideas,

flashgordon · 2006-04-17 11:49:40

http://www.physorg.com/news64499584.html

250 million just to make and store the anti-matter; they've had anti-matter storage since the eighties at least, so they can't be too bad considering the pace of development in the particle physics industries; i guess all that basic research can really pay off!

Commodore · 2006-04-17 12:21:43

$250 million isn't all that bad considering that a CaLV flight of chemical fuel will easily be double that. Depending on the weight of the container, and the feasability of actually launching it, and the fact that a DRM sized transit hab is actually practical for a 45 day trip, this should be seriously considered.

Still, launching it from Earth is an extremely tricky proposition.

Commodore · 2006-04-17 12:29:47

The big question is why is it so expensive to produce anti-matter?

No doubt the equipment is an extremely expensive investment, and its not like theres huge market for it. It also requires huge amounts of energy to produce and store and highly educated people to produce. So is it just the economy of scale? If we sat down and said were going to dedicate a facility to mass produce it, would the price drop significantly?

PurduesUSAFguy · 2006-04-17 13:35:13

Well the energy to produce antimatter in an accelerator is huge, and very inefficent. That being said our understanding of the basic physics issues of anti-matter creation is an order of magnitude more in depth then it was 20 years ago. We should be able to produce gram quantities of anti-matter within the next 10-15 years. Next to that a reliable Penning trap to store it should be a snap. It is quite possible that an anti-matter initiated fusion engine could be the upper stage that sends the first crew to mars, hopefully before 2025.

GCNRevenger · 2006-04-17 14:23:11

Bad cop says:

It looks like they have two different types of engines, one with a more traditional solid core that they just pump positrons into, and a more advanced X-ray ablator version.

Version one isn't worth our time, because a solid core engine can't reach high temperatures, and temperature is everything for thermal engines. A regular nuclear will do just as well, cost less, and be used to generate power. If you will note the diagram in the article, their sold-core thermal engine uses a turbopump just like a nuclear engine would, so it really isn't much safer or simpler.

The merits of version two are also questionable I think, and their "talking points" are suspect:

-"45 days to Mars" sounds alot like "a month to Mars" that all the crackpots like to use.

-This is not the antimatter-ignited fusion engine, which likly requires antiprotons instead of positrons, which are harder to store and generate the superhigh energy gamma rays that we're trying to avoid.

-Marketing it as safer for launch, which is nonsense, since Uranium-235 is perfectly safe and essentially non-radioactive, actually the positron engine is more dangerous. The positron trap is a gamma ray warhead waiting to go off, being launched near populated areas. A regular nuke by comparison cannot be accidently activated.

-Marketing it as simpler, which its not. Rapid-fire highly precise lead pellets as positron "targets" to generate an X-ray pulse does not strike me as "simple." How heavy are these lead pellets? How is this X-ray ablation nozzle going to work?

-Requires shock absorber mechanism like Orion?

-Really safer versus gas-core? The small amount of uranium in the gas core nuclear reactor can simply be dumped overboard after use, nice and clean.

-How reliable is this Penning trap? If it is the slightest bit damaged, won't it overheat and "leak" all at once? That would fry the crew and leave you stranded without power. Uranium for a gas-core engine, on the other hand, is simple to store.

And lets be honest here, NASA Advanced Concepts people, only one notch down from the rediculous "Breakthrough Propulsion Group," trying to save their jobs now that NASA has no use for pouring millions into far off "maybe" projects. And of course you see their little innocuous line:

"If...funds are available to successfully develop the technology."

Short answer: they're not. VSE will still be on a tight budget even after Shuttle is gone, and this looks like a high risk technology to me. Developing a simple solid-core nuclear engine will be much easier and less risky, or else simply investing that ~300M (positrons and trap) would pay for a much much bigger launch vehicle.

In fact, if we have a 120MT class launch vehicle, we don't even need nuclear engines nessesarrily to execute a NASA DRM-III style mission, just a stretched EDS stage with no Lunar lander on top. All chemical, less whining from environmentalists, same number of flights. Just build the bigger rocket for goodness sakes!

I also don't buy their optimism about generating and storing the antimatter being so "easy," they imply that the technology is still a ways down the road, and will cure all their problems if NASA would just send them a few million...

NASA doesn't need new technology, and infact new tech should be explicitly avoided for Mars, it just needs bigger rockets or resurecting old ones (solid core nuclear). Lets just get there first, set up a base, and then we'll talk about superhigh energy engines.

Edited for emphasis

MarsDog · 2006-04-17 14:29:08

The big question is why is it so expensive to produce anti-matter?

Storage problem would be easier if solid antimatter could be produced.
Lithium, a metal, magnetically suspended ?
http://en.wikipedia.org/wiki/Lithium

Float a grain of anti - Lithium close to the pusher plate, then release hydrogen.

flashgordon · 2006-04-17 14:29:21

it's been awhile, so, I can't generate a reference link immediatelly, but I remember some recent news about scooping up anti-matter from the earth's own radiation belts; apparently, there is enough to scoop up!

flashgordon · 2006-04-17 17:03:18

i've recalled that what I knew about 80's anti-matter containers was not that they had just learned how to contain anti-matter, but they had just made and contained anti-hydrogen, so, physicists ability to contain antimatter was at a fairly high level even back then.

GCNRevenger · 2006-04-17 17:37:07

i've recalled that what I knew about 80's anti-matter containers was not that they had just learned how to contain anti-matter, but they had just made and contained anti-hydrogen, so, physicists ability to contain antimatter was at a fairly high level even back then.

Ummmm noooo, thats not true.

There are three basic types of antimatter to be concerned with:

-Anti-protons, heavy and negatively charged
-Positrons, light and positively charged
-Anti-hydrogen, heavy and uncharged

We know how to make all three, but we can't make anti-Hydrogen in any real amount, not even billionths of a gram. Even if we could, we have no way to store it.

Antiprotons and anti-Hydrogen, when they react with normal matter, put off extremely high energy radiation that is very hard to shield against. Positrons are better in this respect, but do not have the same punch as the other two.

We can store antiprotons for relativly long periods of time (weeks perhaps), and probably positrons in a similar fasion, but not anti-hydrogen.

We have no idea how to make anti-lithium or any other multinucleon antimatter.

flashgordon · 2006-04-17 21:19:04

i guess you want me to go prove it!

flashgordon · 2006-04-17 21:36:47

which link did you want?

http://www.google.com/search?hl=en&q=an … gle+Search

well, I've made the same mistake a couple of times myself(not looking things up I could have myself). So, take care!

MarsDog · 2006-04-19 16:54:16

Anti matter production and storage difficulties are not for the near future.
But the link makes you wonder how long:
http://www.hbartech.com/niac_sail1_final.pdf

Lower cost and sooner to launch may be
http://en.wikipedia.org/wiki/Americium
http://www.space4peace.org/mars/nrockets.htm
Recycle smoke detectors ?

GCNRevenger · 2006-04-19 20:11:41

More dreaming...

-Antimatter sails require technologies that I doubt will be practical, for instance how to solidify antihydrogen since macroscopic cooling usually requires contact with the cooling system, or how these fancy antimatter trap chips will supply the antihydrogen as a gas stream.

And this little tidbit about how much production would have to increase versus today: "This represents a production increase factor of 2x107."

But most of all, there is the problem that the accelerations are so low and scaling up antimatter production is not happening. This thing will not have alot higher thrust then an ion engine and will be useless for manned flight, plus the whole vehicle weighs only 200kg. How much antimatter will you need for a 200,000kg spacecraft?

What did interest me though is this power system for the probe, which is a new idea to me. Very light weight compared to an RTG, but how long will the antimatter supply for it last?
___________________________________________

Americium fission daughter particle drive? No way, the radiation hazard would be extreme since it would be so hard to control (if you only need a thin film, how do you turn it off for launch or coast?), and it too would have extremely low thrust. No matter what kind of engine you use, no matter what it is powerd by, thrust and fuel efficiency are inversely proportional. So, if you have superhigh efficiency, you must therefore either have low thrust, or a MASSIVE engine. The specific isotope called for is also very expensive and will never be practical for regular space travel. For goodness sakes, just build the GCNR engine, which involves no new physics and has both high thrust and excelent efficiency, and be done with it.

Also note that this link comes from the "nuclear energy is evil" people, led by that paragon of mushy-headed conspiracy theory Bruce Gagnon, the "Space4Peace" crazies, which seems to attract crackpot scientists like a magnet if you browse their site. Beware though, you might hurt your brain if you look very hard.

VTTFSH_T · 2006-04-20 02:39:17

well, atleast it isn't the solar sail. that thing takes so long to accelerate to high speeds . Antimatter/matter engines using antiprotons may not be efficient now, but 10-20 years down the line, we may be at the point where it is feasible to contain antiprotons.

MarsDog · 2006-04-20 03:13:48

just build the GCNR engine

from: http://www.lascruces.com/~mrpbar/GCNR%20Aero%20Amer.pdf
"The drawback of this design for a GCNR is not as obvious as the spherical system although the problem of the uranium moving to the nozzle is common to both. The major problem of the annular rocket is that it cannot scale up to the diameter necessary to have a critical mass of the uranium. As the radius increases, the thickness of the hydrogen layer gets thinner because the mass flow into the system is held constant. Thus, the cooling layer gets too thin and the walls of the engine will burn through."

Both lower density (to increase area of heat flow)
and lower critical mass could make a difference.
http://www.answers.com/topic/critical-mass-1
http://www.science.co.il/PTelements.asp?s=Density

Likely gas core reactor power plants will be developed to increase efficiency,
then adapted to rockets.

==================================

All the smoke detectors, disposed as garbage, going to waste.
Make gas cored rockets from them ?
http://www.globalterroralert.com/smokedetectorbomb.pdf
http://typhoon.tokai-sc.jaea.go.jp/icnc … .5_022.pdf

GCNRevenger · 2006-04-20 08:27:01

Luckily, there is another design, from the same link, the toridal core design:

"a new geometric configuration for a gas core rocket has been formulated... Conceptually, a high speed jet of gas is injected axially into the reaction chamber. As the jet expands across the chamber, some of the gas will exit through the nozzle but some will be recirculated along the outer wall. The recirculation creates a toroidal vortex.
In a nuclear system, uranium is injected into the vortex"

All you have to do is start the reaction too, perhaps by "igniting" the Uranium with a neutron source, beacuse once it becomes a plasma you could confine the Uranium to sustain the reaction with magentic fields. This would also provide another means of control besides neutron reflection and reduce Uranium loss while the engine is operating. Oh, and increase performance even more too.
_______________________________________________

A "smoke detector" bomb will never work, if your bomb fuel is too fissile it will just blow apart before much of the fuel reacts, and so the bomb will fizzle out and not blow up anything.

Oh, and smoke detectors have half a milligam, not a gram.

GCNRevenger · 2006-04-20 13:06:05

Another thought:

The safety of launching antimatter be much worse then launching a "cold" nuclear reactor... if the antimatter container were to go off course and land near a populated area, say in Florida, it would be basically a radiation bomb tipped balistic missile. Uranium on the other hand, is not really much more dangerous then lead unless it is brought critical, which is impossible to do by accident with a well designed reactor.

Admiral_Ritt · 2006-04-20 13:06:48

The avegage Solar Flare Produces 1 lb of Anti-matter, This includes
Positrons & Anti-Protons. How much Power is that?

E=MC^2 1LB = 454 Grams of Anti-matter

That's 4.09 x 10^16 joules for the taking.

Energy of 1 gram of antimatter 9 x 10^13 joules
Energy of 1 ton of TNT 4.26 x 10^ 9 joules
Heat value of 100 gallons of fuel oil 1.6 x 10^10 joules
Heat value of 20,000 cu ft natural gas 2.1 x 10^10 joules
United States Energy Consumption 10^ 20 joules/year

So What fool can design a sundiver that can survive 5,000K,
By the way the anti-matter exists way up in the chromospehere too not
just in the densest hottest regions of the flares.

GCNRevenger · 2006-04-20 13:12:12

That's 4.09 x 10^16 joules for the taking

...is 4.09x10^16J that we can't capture or use

Admiral_Ritt · 2006-04-20 13:41:02

That's 4.09 x 10^16 joules for the taking.

Sure For Interplanetary Travel you would only need a couple of grams, and
could be produced on earth.

But since EMC still applies, this means that any manned interstellar
ship will require a few pounds, which means the amount of energy
extracted from the Anti-Matter was the same as the amount of energy needed
to create it on earth. For ten pounds of the stuff that's
4.09 x 10 ^17 Joules. Which is Approximately the Entire output of all
the Energy Generated by the USA in 3.5 days, assuming total conversion
which is fantasy.

MarsDog · 2006-04-20 16:08:39

The avegage Solar Flare Produces 1 lb of Anti-matter, This includes
Positrons & Anti-Protons. How much Power is that?

And the charged antimatter would be concentrated by the magnetic field.
Making it easier to intercept. Even use it to power the collecting craft.

Closer to home, does the Van Allen Belt trap the antimatter from the solar wind ?

Half of antimatter energy lost to neutrinos, next best is,
Antimatter catalyzed nuclear pulse propulsion:
http://en.wikipedia.org/wiki/Antimatter … propulsion

GCNRevenger · 2006-04-20 17:46:05

Oh boy, here we go again with another "idea:"

So let me get this straight... you want to park a ship or space station into solar orbit over a sunspot, wait for a flare to occur, then use a very large magnetic field to funnel and capture the antimatter created?

-Sunspots are 10,000-50,000km in diameter, and so if you are parked in orbit some distance away, you will need a magnetic funnel around 1,000,000km wide I would guess to capture the majority of the antimatter.

-How do you make a field that big, while still being intense enough to deflect charged particles traveling not too far from the speed of light? It would be near impossible to bend the path of ANY particle going that speed from a distance, remember that the strength of magnetism decreases exponentially with distance just like gravity.

-Solar flares also release lots of regular matter. Tens or hundreds of thousands of tonnes of it infact. It has a charge too, and will be funneled into your collector along with the antimatter, and because they have exactly the same mass you can't really seperate them. All the antimatter will be destroyed before you can bottle it because the normal matter will mix with the antimatter first.

-Sunspots don't usually occur on the equator of the sun, so there is no stable orbit that will park you directly over sunspots with any regularity, so you would just have to hope your inclined orbit coincides with a sunspot spawning a solar flare, which given the size of the sun and the long time of the orbit is nil.

-You will have to be quite close to the sun to collect the antimatter before it is normally destroyed, how will you protect your ship from the heat and solar wind?

-Assuming you can do the above, how will you protect your ship from the direct blast at close range from the sunspot? The vast amount of energy, plasma, and radiation would obliterate any concieveable defense. If you thought reentry was rough on space ships, you've got another thing coming.

-Won't the massively powerful magnetic field of the sun, and sunspots imparticularly, disrupt your magnetic funnel and prevent you from capturing anything?

-The massive inertia of tens or hundreds of thousands of tonnes of plasma traveling a good fraction of the speed of light is astronomical; it will be more than sufficent to blast your antimatter ship/station with its magnetic funnel/sail right out of the solar system. You'd have to burn all your antimatter just to keep from flying off into the icey black forever, even if you could capture any.

Remember: matter and antimatter are functionally identical except for their charge, so your magnetic funnel will catch normal matter just the same as it would antimatter, there is no way to catch one but not the other.

GCNRevenger · 2006-04-20 18:25:14

Oh, and you will have a similar problem about funneling up normal matter with the antimatter if you fly a funnel-equipped ship around Earth's magnetic belts.

And as far as producing the antimatter on Earth, there is no way you could safely launch very large quantities even if you could make it. If Uranium leaks, its no big deal, but if antimatter "leaks" it produces a gamma ray pulse.
_____________________________________________
Antimatter-initiated fission/fusion is plausable, but too rube-goldberg for my taste:

-It still requires a very, very precise mechanical mechanism to expel the fuel particles, and each of them must be very carefully produced from Uranium/Plutonium and Trintium/Deuterium.

-Since the engine will not be as high a thrust as a rocket of any sort, this mechanism will have to operate for long periods of time reliably. A nuclear rocket would only have to operate minutes or hours.

-Requires a method to release controlled amounts of antiprotons with very precise timing. No such methods exist today, but turbopumps for nuclear rockets are a mature technology. How do you release only some of the antiprotons and not all of them all at once anyway?

-Antiproton annihilation, not positons, are required to initiate the reaction. While relativly simple to produce the required quantity, the annihilation produces a hypra-energetic form of gamma ray much more powerful then produced by nuclear fission, which will be extremely difficult to shield against by any practical material.

-A very large amount of neutron radiation will be produced by the annihilation and subsequent fusion reaction, which might be a problem for damaging said mechanism.

-Antiprotons require active storage systems, where if power (electrostatic) or cooling (magnetic) is interrupted, you could lose all your "fuel" and be dead in space. Emphasis on "dead" since you couldn't use aerobraking with such an ungainly ship if you lost antimatter containment.

-If pulses are substantial, you will require a heavy shock absorbing mechanism to protect the rest of the vehicle from vibration, which has "no place to go" in space.
___________________________________________
And from a practical standpoint...

-In the longer term, when we want regular flight between worlds, scaling up antimatter production would be difficult, and the danger of regular shipments and storage in orbit would be signifigant.

-There will not be any facilities to create antimatter or fuel pellets on Mars or the Moon for a century at least with present day physics of production, and betting that some breakthrough will make it easy later is wishful thinking. Emphasis on "bet."

On the other hand you can refuel a GCNR engine with Hydrogen produced locally from Martian water and use Uranium from Earth, which will radically reduce how much fuel you have to carry to and from Mars. Research bases on the outer planets will also bennefit from this fact, but neither Mars nor any body save the Earth will have a supply of enriched Uranium for probably at least three quarters of a century for an antimatter fission/fusion engine, which will require substantial quantities.

Uranium is also inherintly safe, its really not much more dangerous then lead. Antimatter on the other hand, if your storage vessel were to fail and leak, everyone within a kilometer or so would get a lethal gamma ray dose that cannot be blocked except by the heaviest shielding.

Admiral_Ritt · 2006-04-20 19:00:32

I you were to try to scoop out Anti-Protons from the Upper layers of the
Solar Corona, Your Gathering Systems would have to be:

1) A mutiple set objects, since you could loose one easily to a major
flare at just the right/Wrong Place.

2) Wishtand repeated encounters with 5,000K temperatues

3) Not Dependent on Electronics for guidance, It would have to
be in a dipping Eliptical Orbit.

4) The magnetic elements would have to be solids.

5) It would take many orbits

6) You would have to rendezvous with this gathering vesel, to decant it's
contents.

7) All robotic rendezvous ships obcourse.

8) would it really cost less than Accelerators??

GCNRevenger · 2006-04-20 21:06:36

An economical operation can't afford to lose many of these ships to being "in the wrong place" often you know...

And I don't think you can prevent your vehicle from deorbiting and burning up, it will still have drag you know.

I don't think that you are really grasping here... the upper atmosphere of the sun has lots of regular matter in it too, and there isn't any good way to seperate this from the antimatter before they combine and fizzle out. When you try and scoop up the antimatter, a magnetic funnel will scoop up regular matter too, and both will be squeezed together before it reaches your collector.

And it does fizzle out, if it didn't, antimatter would build up in the sun's outter atmosphere, which it doesn't. Otherwise, the sun would generate lots more gamma rays of a very specific energy, which it doesn't.

I also doubt you can have a magnetic funnel that extends very wide, if you are that close to the sun the field disruption will be intense. You can't have a totally unguided vehicle either, the magnetic field of the sun is so strong thtat it would interact with the funnel, and active navigation would be non-negotiable. If you got too close though, you would get fried.

No, it really wouldn't be any cheaper then accelerators.

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#1 2006-04-17 11:49:40

Re: New anti-matter engine ideas,

#2 2006-04-17 12:21:43

Re: New anti-matter engine ideas,

#3 2006-04-17 12:29:47

Re: New anti-matter engine ideas,

#4 2006-04-17 13:35:13

Re: New anti-matter engine ideas,

#5 2006-04-17 14:23:11

Re: New anti-matter engine ideas,

#6 2006-04-17 14:29:08

Re: New anti-matter engine ideas,

#7 2006-04-17 14:29:21

Re: New anti-matter engine ideas,

#8 2006-04-17 17:03:18

Re: New anti-matter engine ideas,

#9 2006-04-17 17:37:07

Re: New anti-matter engine ideas,

#10 2006-04-17 21:19:04

Re: New anti-matter engine ideas,

#11 2006-04-17 21:36:47

Re: New anti-matter engine ideas,

#12 2006-04-19 16:54:16

Re: New anti-matter engine ideas,

#13 2006-04-19 20:11:41

Re: New anti-matter engine ideas,

#14 2006-04-20 02:39:17

Re: New anti-matter engine ideas,

#15 2006-04-20 03:13:48

Re: New anti-matter engine ideas,

#16 2006-04-20 08:27:01

Re: New anti-matter engine ideas,

#17 2006-04-20 13:06:05

Re: New anti-matter engine ideas,

#18 2006-04-20 13:06:48

Re: New anti-matter engine ideas,

#19 2006-04-20 13:12:12

Re: New anti-matter engine ideas,

#20 2006-04-20 13:41:02

Re: New anti-matter engine ideas,

#21 2006-04-20 16:08:39

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#22 2006-04-20 17:46:05

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#23 2006-04-20 18:25:14

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#24 2006-04-20 19:00:32

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#25 2006-04-20 21:06:36

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