Re: The Cold Equations


Dr John Stockton wrote:
> JRS: In article <1133724844.008385.174180@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> , dated Sun, 4 Dec 2005 11:34:04 local, seen in news:sci.space.shuttle,
> William.Mook@xxxxxxxxx posted :
> >Depends on the isotopes - but, yes, there are isotopes wih the
> >half-lives you mention. This means they have correspondingly lower
> >power levels to weight, hence thrust to weight.
> >
> >Dr John Stockton wrote:
> >> JRS: In article <1133388684.900150.130900@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> >> , dated Wed, 30 Nov 2005 14:11:24 local, seen in news:sci.space.shuttle,
> >> William Mook <william.mook@xxxxxxxxxxxxxxxxx> posted :
> >> >
> >> >Radium to Radon to Lead emitting ions to produce thrust would produce a
> >> >low to lower level of thrust halving their output every 10 days or so -
> >>
> >> The half-life of Radium is about 1620 years; such an engine would
> >> correspondingly have longer service life and lesser thrust, each by a
> >> factor of around 50000.
> >>
> >> --
> >> ©
>
>
> Don't quote signatures.

Don't tell me what to do.

>
> Respond after trimmed quotes.

Don't tell me what to do.

> Don't keep changing your E-identity; it is a discourtesy to users of
> kill-files.

Nonsense.

>
> The term "Radium" without qualification means the natural isotope,
> Rn 226, which has a half-life of 1620 years or so.

No it doesn't. The term radium without qualifiers means radium without
qualifiers.

> Radon is a direct decay product of Rn 226.

Um, 'Rn' is the symbol for Radon, I believe you mean Ra 226 don't you?
Sheez.

Bud, there are only two isotopes of radium that have half-lives greater
than 1 year - and are of concern to the Department of Energy
Environmental Management Agency;

Ra 226 1600 yrs 1 Ci/g alpha (4.8 MEV)
Ra 228 5.8 yrs 280 Ci/g beta (170 kEV)

Its hard to tell from the original post whether or not the proposed
rocket was to use alpha particles (helium nuclei) or beta particles
(electrons) for the production of thrust.

But, there are other isotopes that are much more highly radioactive -
and these proceed by alpha decay.

These isotopes have vanishingly short half-lives, and correspondingly
greater activity. High activity means a far greater power to weight
ratio. High power to weight means a far higher thrust to weight ratio.
High thrust to weight makes them more suitable for a rocket
application.

Despite this, NONE appear suitable as a practical rocket. Which is my
point from the beginning. Nothing you say changes that. The most
favorable radium isotope for rocket applications appears to be;

Ra 224 3.7 days 160,000 Ci/g alpha (5.7 MEV)

Radon as the original post pointed out also decays radioactively by
releasing alpha particles. These have very short half lives as well -
one has nearly the exact same half life and activity as the Radium 224;

Rn 222 3.8 days 160,000 Ci/g alpha (5.5 MEV)

So, since the original post mentioned both Radium and Radon as thrust
producers, this combination came to mind, and so I talked about *that*.

But there are MORE active materials than Radium and Radon - check it
out;

Rn 220 56 sec 930 million Ci/g alpha (6.3 MEV)

One king of natural radioactivity is an isotope of Polonium that has an
astoundingly high rate of radioactive decay - Po 212 - which has a half
life of 310 nanoseconds an a radioactivity of 180,000 TRILLION Ci/g

Po 212 310 ns 180,000 trillion Ci/g alpha (8.8 MEV)

Which is a TRILLION times more active than the highest activity
Radium/Radon combination - but its very hard to store in any quantity
any length of time!


Here's my source of information;

http://www.ead.anl.gov/pub/doc/radium.pdf






> --
> © John Stockton, Surrey, UK. *@merlyn.demon.co.uk / ??.Stockton@xxxxxxxxxxx ©
> Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
> Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
> Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036)

.

Relevant Pages

  • Re: The Cold Equations
    ... >Depends on the isotopes - but, yes, there are isotopes wih the ... >half-lives you mention. ... >power levels to weight, hence thrust to weight. ...
    (sci.space.shuttle)
  • Re: Atomic ramjet for exploring Titan
    ... than a micron - even if its pure radon. ... all you have to do is carry Radium around with you right? ... Power level is equivalent to thrust. ... There are 32 isotopes of Radium and only Radium 226 decays to Radon ...
    (sci.space.policy)
  • Re: Atomic ramjet for exploring Titan
    ... than a micron - even if its pure radon. ... all you have to do is carry Radium around with you right? ... Power level is equivalent to thrust. ... There are 32 isotopes of Radium and only Radium 226 decays to Radon ...
    (sci.space.policy)
  • Re: Atomic ramjet for exploring Titan
    ... than a micron - even if its pure radon. ... Extracting large amounts of radium from our Selene/moon shouldn't ... Power level is equivalent to thrust. ... There are 32 isotopes of Radium and only Radium 226 decays to Radon ...
    (sci.space.policy)
  • Re: Carbon-14 fallacy in dating
    ... the radiogenic isotopes we see are in just the combinations ... and quantities to be expected from an earth that's billions of years ... We see isotopes with long half-lives, ... decay products of those with long half-lives. ...
    (talk.origins)