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Oct 1, 2012

Debunking Antimatter Rockets for Interstellar Travel

Posted by in categories: education, engineering, physics, policy, space

Previous Post in this Debunking Series.

Why is it necessary to debunk bad or unrealistic technologies? If don’t we live in a dream world idealized by theoretical engineering that has no hope of ever becoming financially feasible. What a waste of money, human resources and talent. I’d rather we know now upfront and channel our energies to finding feasible engineering and financial solutions. Wouldn’t you?

We did the math required to figure out the cost of antimatter fuel one would require just to reach 0.1c and then cost at that velocity, never mind about reaching Alpha Centauri.

Table 2: Antimatter Rocket Fuel Costs to Alpha Centuariat 0.1c (in metric tons)
Source of Estimates Amount of Antimatter Required Maximum Velocity

Spacecraft Mass

Cost of Antimatter per kg

(metric tons) (metric tons)

Gerald Smith

NASA

2.5E+16

6.25E+16

Total $ Cost of Fuel for Trip

A Poor Formula for Interstellar Travel

5

0.1c

2,000

1.25E+20

3.13E+20

Project Valkyrie

100

0.1c

100

2.5E+21

6.25E+21


The table above compiled from various sources shows that the cheapest cost of just reaching 0.1c velocity is of the order of $125,000,000,000,000,000,000. This so unthinkably large even I don’t know how to conceptualize it, and by comparison, conventional rockets appear realistic!

Also note that the large variations in the estimates of the amount of antimatter required combined with the larger variations in the mass of the spacecraft antimatter engines could propel. That is no one reallys has a handle on what this would take.

But wait, let me quote EJ Opik, “Is Interstellar Travel Possible?” Irish Astronomical Journal, Vol 6, page 299.

The exhaust power of the antimatter rocket would equal the solar energy power received by the earth — all in gamma rays (and Opik quotes Carl Sagan, Planet. Space Sci., pp. 485–498, 1963) “So the problem is not to shield the payload, the problem is to shield the earth

I don’t need to say more. Debunked.

Next psot in this Debunking Series.

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Benjamin T Solomon is the author & principal investigator of the 12-year study into the theoretical & technological feasibility of gravitation modification, titled An Introduction to Gravity Modification, to achieve interstellar travel in our lifetimes. For more information visit iSETI LLC, Interstellar Space Exploration Technology Initiative.

Solomon is inviting all serious participants to his LinkedIn Group Interstellar Travel & Gravity Modification.

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Comments — comments are now closed.

  • ab on October 2, 2012 8:40 am

    and for which engine you figured out this cost?
    i mean is it for 1)beam core engine
    2) solid core
    3) gas core
    4) plasma core
    and the min vel we will get if we develope beam core engine is .33c and max is .89%c.

    i wanna know much about antimatter engine.
    please give me whatever knowledge you have about antimatter propulsion

  • Benjamin T. Solomon on October 2, 2012 11:26 am

    ab, I always enjoy a good dialog, but this obviously is not one of them. Let me explain.

    The usage is per reported by the various authors. You need to click on the links and do your own research, if you are really interested in finding out more.

    I’m doing quick and dirty calculation per NASA’s and others’ costs estimates. Antimatter engine fuel costs are on the order of $1E20. That is if you reduce the costs of antimater drives by a factor of a billion, the costs would still be on the order of $1E11, to make it comparable to the unrealistic costs of conventional rocket propulsion.

    The primary objective of this exercuse is to determine whether anyone I would employ (should that day come) should waste their time, effort and talent exploring these engine designs. Obviously not.

    At some point we have to draw the line between academic exercises (useful for understanding a theory or passing a test) and real world engineering feasible solutions.

    That is why I term these types of explorations as ‘theoretical engineering’, they are fun to do, gives you a sense of accomplishment but out of touch with reality.

  • Jimmy Nolan on October 2, 2012 5:29 pm

    I think aneutronic propulsion will be far cheaper and safer than antimatter. http://youtu.be/ro5-QYqqxzM

  • Benjamin T. Solomon on October 2, 2012 5:46 pm

    Jimmy Nolan, that is a good thought. And the video looks very nice. Now put some numbers to your statement, and lets see how things work out.

  • Tom Kerwick on October 3, 2012 5:06 am

    Benjamin — I feel it is more important to review the methods on which antimatter can be produced, and whether there is a feasible case to make this a less expensive process. As regards EJ Opik’s comment, I would suggest that such an antimatter drive would only be enabled after the initial launch once a safe distance from Earth, and alternative methods would be used for the initial launch of such a craft. So not necessarily debunked as yet…

  • Jimmy Nolan on October 3, 2012 7:02 am

    matter-antimatter helium-3 p-B11
    90000 TJ/kg 204 TJ/kg 66TJ/kg
    $62.5trillion/gram $4000/gram $5/g

    Most of the energy produced by antimatter is the form of neutrinos and gamma rays that are almost useless for energy generation and propulsion. On the other hand, most of the energy produced by aneutronic fusion is mainly in form of charged alpha particles that can be easily deflected/shielded by electric/magnetic fields and directly used for electricity generation and propulsion. Furthermore, antimatter is much harder to be obtained/produced and stored. In short, helium-3 and p-B11 are far cheaper and safer without the disadvantages of antimatter.

  • Benjamin T. Solomon on October 3, 2012 3:38 pm

    Jimmy Nolan, I cannot quite follow your numbers. Can you provide more explanations?

  • Benjamin T. Solomon on October 3, 2012 3:48 pm

    Tom Kerwick, you have a valid point, but I suspect that Carl Sagan was not even thinking of launching from Earth, but from space.

    There many factors to be considered to make real engineering happen. 1) costs, 2) technological feasibility & 3) safety. And at least these three must be present before proceeding.

    Right now 1) & 2) are the main reason for debunking anitmatter engines, because costs are on the order of $1E20, and per John Eades real world experience working with antimatter at CERN
    http://lifeboat.com/blog/2012/08/new-findings-on-the-antimatter-drive
    this is considered impossible for now.

    Yes, we could do something in 200 years but that is not relveant for today, tomorrow or within the next few decades.

    I cannot stress the importance of distinguishing between real world engineering feasibility and ‘theoretical’ engineering. One way is to ask the question, if you had a few millions dollars can you demonstrate experimental feasibility as a propulsion devices, in the next few years? If the answer is not yes, then we are dealing with ‘theoretical’ engineering, which looks really good on paper, gives you a really great feeling of achievement, but out of touch with reality.

    Therefore debunked.

  • Tom Kerwick on October 5, 2012 3:12 am

    “Yes, we could do something in 200 years but that is not relveant for today, tomorrow or within the next few decades. ”

    Then we are in agreement.