# Nasa's new and improved ANTI-MATTER space ship

• NASA
Astronuc said:
From the Cern Antimatter site -
It's a good thing they only need 10 mg.
http://www.antimatterenergy.com/stoage.htm [Broken] isn't a CERN site. Browsing around there's some rather odd pages, such as claiming comets are made entirely out of antimatter.

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Astronuc
Staff Emeritus
AlphaNumeric said:
http://www.antimatterenergy.com/stoage.htm [Broken] isn't a CERN site. Browsing around there's some rather odd pages, such as claiming comets are made entirely out of antimatter.
Oops. I went through the CERN link on that page to the LHC pages.

Here is the page to which I was referring with regard to size of a accelerator/collider/storage ring - http://public.web.cern.ch/public/Content/Chapters/AboutCERN/CERNFuture/HowLHC/HowLHC-en.html [Broken]

The cost for antimatter is actually estimated on a NASA page -

antimatterenergy.com does have two nice pictures, one each of Fermilab and CERN.

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pervect
Staff Emeritus
I just noticed this thread. While I think antimatter rockets are interesting theoretical exercises, for an actual mission I think that nuclear-thermal or nuclear-electric propulsion makes a lot more sense.

The biggest problem is probably political - we'd have to put a nuclear reactor in space.

Of course, this is hardly new news. See for instance

http://www.fas.org/nuke/space/c07sei_1.htm

A - PROGRAM HISTORY

Responding to the President's (ed: Bush Sr.) July 1989 speech, NASA prepared a blueprint for achieveing these goals, known as "the 90 Day Study" (discussed below). On 19 December 1989 Vice President Quayle, who chairs the National Space Council, wrote to NASA Administrator Richard Truly requesting study of "different architectures, new systems concepts, promising new technologies, and innovative uses of existing technologies" to implement the SEI. This was included in a Presidential National Security Directive on 16 February 1990, which established the "Synthesis Group" to evaluate these alternatives.

The Synthesis Group was chartered by the National Space Council in the Summer of 1990 to review NASA plans for the Space Exploration Initiative, as well as to incorporate suggestions from other sources. It will recommend at least two alternative architectures for SEI implementation, one of which has been characterized as "nuclear rich." Although the deliberations of the Synthesis Group will continue through March 1991, this review process has already reached a number of preliminary conclusions:

"1 - Contrary to popular opinion, the first trip to Mars may have to be fast rather than slow, because humans are the weak link in the chain; human psychology is a big unknown.

"2 - One architecture proposed by the Synthesis Group will be "nuclear rich" because nuclear is probably safer and cheaper (and faster).

"3 - There has been a discussion about improving the overall system reliability by using multiple engines, i.e., rather than trying to put all of the reliability in one engine, have "engine-out" capability so that the overall system reliability is high.

"4 - Chemical/Aerobrake will probably cost tens of billions of dollars to develop and prove out and doesn't provide much gain. It was described as "disappointing.""(1)

General Stafford has testified that:

"Today it looks like technology has advanced so that in the year 2010 or 2020 a nuclear thermal rocket would certainly be feasible, assuming that you added all the safety criteria and had political acceptance... We are convinced that nuclear rocket propulsion can make an important contribution to the Space Exploration Initiative if it proves feasible and safe and can gain public acceptance. For example, a nuclear thermal rocket can reduce the travel time to Mars by 60-70%."(2)

Cycle of boom and bust

"If one stood on top of a pile of all the studies of space nuclear power that have been performed over the past 20 years, one would be several feet closer to Mars…at least during some hours of the day," explained Steven Aftergood, head of the Project on Government Secrecy for the Federation of American Scientists in Washington, D.C.

Aftergood noted in a recent newsletter that, as a technology enterprise, space nuclear reactors have been "subject to a remarkable cycle of boom and bust over the past 50 years."

Start-stop work has dead-ended ambitious programs every decade or so, Aftergood said, noting the SP-100 program – a NASA, Department of Defense, Department of Energy initiative -- that was killed ten years ago after some \$400 million had been doled out.
Other related Mars efforts are looking at the approach of just accepting a longer mission, for instance

http://pda.physorg.com/lofi-news-gravity-artificial-centrifuge_3921.html [Broken]

(This isn't a new idea either). My prediction - more flip-flops as politicians (mainly) waffle on the issue.

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Might it be equally practical to build a small scale fusion reactor? I mean, we'll need exotic materials either way, right?

dimensionless said:
Might it be equally practical to build a small scale fusion reactor? I mean, we'll need exotic materials either way, right?
They should just dump the anti-matter space ship and use nuclear fuisson. It's alot more realistic.

What about antimatter catalyzed fusion??? I heard about it some time ago.
Is this a seriuos proposal?

kaos said:
Is this a seriuos proposal?
Well since Antimatter is hard to produce and it's extremley rare in nature, I don't think anything involing antimatter would be serious proposal untill more advacements in technology.

pervect
Staff Emeritus
kaos said:
What about antimatter catalyzed fusion??? I heard about it some time ago.
Is this a seriuos proposal?
It's being actively reasearched at the university of Pennsylvania, see for instance

http://www.engr.psu.edu/antimatter/introduction2.html [Broken]

(Technical details are in the documents section).

I tend to agree that a fission rocket would be more realistic, though - if we were really serious about getting to Mars.

Rather than digress on the role "pork-barrel politcs" in US space policy, though, I'll simply say that low levels of funding for far-out projects like the UPenn antimatter proposals should/could be viewed as being in the category of fundamental research rather than a short-term engineering development proposal.

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Andrew Mason
Homework Helper
scott1 said:
http://www.nasa.gov/centers/goddard/news/topstory/2006/antimatter_spaceship.html" [Broken]
Where are they going get anti-matter and is this even possible with technology we have now
I would have thought that a design team would be brought in when the concept was clear and it is just a matter of working out the technical stuff.

A positron engine has serious conceptual problems. Since a positron/electron annihilation produces 2 gamma rays each going in opposite directions, if you want to make it work as an engine, you have to either 1. capture both gamma rays and use the resultant heat to propel matter out one end to produce thrust, or 2. capture one and direct the other out the back and use the resulting photon momentum: $p = h/\lambda = E/c$ to propel the ship or 3. a combination of 1 and 2.

In either case, you have to have a lot of lead and lead is massive. In 1, which is just a conventional rocket engine with a different heat source, you need a supply of mass to expel - eg. hydrogen.

In 2. and 3 you need to be able to direct the gamma rays. Even then, I think the thrust would be minimal. For 10 mg. of positrons, the maximum thrust would be:

$$p = E/c = mc = 10^{-5}\cdot 3\cdot 10^8 = 3,000 kg m/sec$$

or enough to increase the speed of a 3000 kg ship by 1 m/sec.

Perhaps the date on the article is wrong. It should have been 4.1.06.

AM

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pervect
Staff Emeritus
The technical details are at http://www.engr.psu.edu/antimatter/Papers/ICAN.pdf [Broken]

Another good website is

http://ffden-2.phys.uaf.edu/213.web.stuff/Scott Kircher/fissionfusion.html

The proposal is far-out, not silly. IMHO it makes a lot more sense to fund something like this than to start (and stop! - look at the history) yet another nuclear fission rocket program that won't actually be launched, even though nuclear fission rockets are known to work and capable of doing the job of a Mars mission. (They are known to work because we've actually built and tested some, back in the days when enviornmental regulations were not so tough).

Where would the antimatter come from? Let's quote from the Upenn proposal in detail.

Antiproton sources exist worldwide at two sources, CERN in Geneva, Switzerland and Fermilab, in Batavia, Illinois.
These two laboratories utilize high energy proton synchrotron accelerators, with accumulator storage rings attached to
collect antiprotons produced by collisions of protons on targets. Presently, Fermilab collects 6 x 1010 antiprotons per hour
in its Accumulator. This means that in one year of dedicated production, it could produce a maximum of 0.85 ng of
antiprotons. A new and funded facility, called the Main Injector, will turn on in 1999, with a maximum annual production
capacity of 14 ng. A new Recycler Ring presently under construction and located inside the Main Injector ring will increase
the collection rate by another factor of 10. This would place Fermilab in the 100 ng range, making it attractive for future
space applications.
It is estimated (I haven't gone over the details) that about 140 ng would be needed for a mission to Mars, this is about 1-2 years supply from Fermilab, after it is upgraded.

It's estimated that a single shot takes only 10^11 antiprotons. That's 1.6e-13 grams. 140ng would give enough antiprotons for about 850,000 shots. This is larger than the 450,000 shots I calculate from the reference design in the ican-2 paper.

Here's the appropriate quote from the Upenn paper:

In 1992 large fission and neutron yields from antiproton annihilation at rest in a natural uranium target were observed by
our group.1 Calculations indicate that short bursts of antiprotons could induce temperatures of several keV in a small
compressed pellet.2 These conditions are appropriate for ignition of a hydrogen fusion burn within the microsphere. Targets
with yields up to 302 GJ have been considered, with compression provided by light ion beams or lasers. Baseline parameters
for ignition are: antiproton energy, 1.2 MeV; number, 10^11; pulse length, 2 ns; and deposition volume, 1 mm3. An experiment
at the Phillips Laboratory to demonstrate subcritical antiproton-catalyzed microfission is in progress.3-7

Remember that the antimatter here is not being used to directly propel the space-craft. It is being used to create a fission reaction which will create a fusion reaction, and the fission + fusion will actually be used to power the spacecraft.

The antimatter is not even the sole heating source, if one reads the technical specs - ion beams are also used in the design.

Of course, when one looks at the 700 ton design, and figures out how much it will cost to get all that mass into LEO, one sees that the biggest problem is getting the thing off the ground :-)

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laurelelizabeth
I thought I read somewhere we have enough to heat a cup coffee.
In the movie Apollo 13 (which was based on reality) didn't they say that it only had enough power left to power the coffee maker for 8(?) hours? And then they managed to use gravity to their advantage and get it back :)

So it sounds feasible, not now but in the future... But it would be another thing to worry that terrorists might get a hold of. With destructive technology like nuclear weapons and stuff, every country has to be more mature about that sort of stuff

russ_watters
Mentor
That comment in Apollo 13 was about electricity for powering their electronics. The energy released by their engines in course correction burns was, of course, many many many orders of magnitude larger than that.

laurelelizabeth
That comment in Apollo 13 was about electricity for powering their electronics. The energy released by their engines in course correction burns was, of course, many many many orders of magnitude larger than that.
oopsie.

well we built cars, planes, and made electricity. All things are possible! The question you should be asking is will the human race survive long enough to figure it out, or will we just make bombs out of it, and sell it to people that hate us, so they can fulfill there ultimate goal of making jesus come back? Jesus was cool, he was the only white guy in the desert:-)