Star ships have visited the Earth since the dawn of history. The type that
used microwave photon rockets have the characteristic dish shape called a
"flying saucer" Adamskii described his contact with one of these. (ET was
alleged to have saved him from death by dehydration in an American desert).
Another type uses light photon rockets and here the rocket motors are much
smaller. Lazer describes these in some detail.
The photon rocket has the highest specific impulse and is the only type of
rocket capable of interstellar travel.
It is straight forward to calculate the limitations of photon rockets. If
thermonuclear fusion of hydrogen is used as the fuel, then the mass defect
gives you the mass ratio that can be achieved and my calculations using the
relativistic rocket equation give an upper limit of about 1/5 of the
velocity of light. That is from memory.
When I was working at a British space research establishment thirty years
ago and visiting French scientist and I worked out the design of a small
automated star ship to travel to Banards Star where there is believed to be
a planetary system of at least three planets. It was a nuclear (uranium
pile I think) powered klystron to make a microwave photon rocket. It had a
camera and spectroscope and a planet detector. It was launched, he told me,
in about 1969 and used very slow morse telegraphy to send data and images in
hex. The last I heard was that it was spiralling out of the solar system.
It was lanched into earth orbit and slowly spiralled out of the earths grip.
I do not know the power or the weight, but I understand it was small and
light. His name (of the French Scientist) I knew as Piere, but I do not
The photon rockets that ET use must be able to totally convert matter into
energy in their reactor power units to give velocities in excess of 99
percent of the velocity of light because contactees tell of interstellar
flights only lasting days or weeks.
Their description indicates that the velocity of a starship travelling at
these high velocities can do the return journey without any time dilatation
but their transit time indicates that the velocity is the 4-velocity in
relativisic physics. I find this incomprehensible.
I have had ET contact experiences that has lasted all my life but I have
only seen the equipment and on a six month journey to a local star with
Hilary, a girl I was engaged to, we were only way six months. The main
engine, externally, looks like the proton syncrotron at the Rutherford
laboratory but it is not a particle beam acceletator. ET gave me to
understand that it was a sort of very high pressure and temperature vessel
where matter is so highly compressed with high energy collisions that the
mass - energy is converted into radiation which is coupled by electrons to a
very high power microwave (2 GHz) emission. This it taken by big waveguides
to the outside where the refelector focuses the radio energy into a narrow
beam. This gives propulsion by photo reaction. The force is given by
(Power/c) where power is the energy released per second by the engine. If
the energy is given by mc^2 then where m is the mass of matter destroyed per
second, then the force of the rocket is given by mc. You can then calculate
the mas ratio for a space craft of say 20,000 tonnes carrying mostly fuel at
the start. If you want a warp factor of 100 to give short transit times the
mass ratio has to be 1:99 (If I remember correctly) so for each tonne of
all up weight only 1/99 is payload. So for an initial weight of 20,000
tonnes only 20,000/99 or 200 tonnes (approximately) will be payload. For a
warship then speed is very impotant and mass ratios of over 1000 would be
needed giving a warp factor of 1000 or more. Such craft would need mostly
fuel in their hull.
I understand the fuel is hydrogen processed into mercury. Power levels of
the photon rockets are likely to reach 10^17 watt. But I am unsure of this.
They refuel from planets like Jupiter over a fairly long period.
"Jason H." <exosearch@xxxxxxxx> wrote in message
> Essay - SETI politics - by Gregory Anderson (Sept. 6,')05
> Mr. Anderson observes the rock and a hard place that SETI finds itself,
> in particular
> "...Getting money and striving for respect, however, seems to have put
> SETI researchers like Seth Shostak and Jill Tarter in a box. To justify
> continuing SETI work, they must argue that the existence of advanced
> technological civilizations elsewhere in the Milky Way, given what
> modern science knows, is perfectly possible. On the other hand,
> however, largely to build the respectability of their efforts, they
> also argue that interstellar travel is so difficult, and will always
> remain so, that no civilization will ever master it. That stance
> accomplishes two objectives. First, it dismisses the idea that UFOs
> might be interstellar craft. Second, it enshrines SETI-their
> passion-as the only way to ever answer the question: Are we
> Although I too have criticized the SETI Institute for ingnoring a
> search for interstellar spacecraft, I've never read or heard the Dr.'s
> Shostak and Tarter argue that "...no civilization will ever master..."
> interstellar travel. I agree that the politics/giggle factor (and the
> persistent lack of evidence) prevent them from delving into this
> subject as a scientific objective, but it does'nt seem logical (IMO)
> that the Dr.'s Shostak and Tarter would ever say "...that no
> civilization will ever master it." (Why would a scientist argue
> something so unprovable? :^); I think that perhaps they just believe
> that it's easier, cheaper, and therefore more plausible, for ET to send
> a message and explore the universe via photons. (It is a shame though
> that the SETI Institute seems to be forced by circumstances of social
> acceptability to ignore the possibility of searching for interstellar
> ET spaceprobes or relics within our solar system.)
> Regards, Jason H.