Microwave beamed power

Has anybody investigated the use of microwave beamed power as a way of
eliminating the first stage of a rocket?

To put it more precisely to assist a rocket by beaming microwaves to it
and to use these microwaves to heat the air as it goes through a ramjet
like engine. Higher up where there is no air it could heat pure
hydrogen that is expelled from a tank. This would be like a solid core
nuclear rocket engine but would not have any radiation nor shielding
issues.

I am pretty sure that large amounts of microwaves can be cheaply made
with vacuum tubes and beamed up by a ground based power station. I also
know they can be received by antennas and converted to DC power by
diodes, but this would not be the best way in this case. We would have
to heat the hydrogen somehow using the incoming microwaves. Perhaps
some kind of microwave absorbing tubes could be used that can also
stand high temperatures. Like some kind of ceramic coated refractory
metal.

Any thoughts are appreciated.

Z

zoltan wrote:
Has anybody investigated the use of microwave beamed power as a way of
eliminating the first stage of a rocket? [...]

You want to look to the work of Liek Myrabo.

He's done too much to summarize easily in one posting, but he has
looked at a large number of laser and microwave externally powered
rockets and ramjets of various types.

A number of his more advanced concepts are thought by other experts
either to not work, or be so speculative as to functionally be
science fiction. However, he also has done test flights of more
nearterm practical stuff such as pulsed laser / air propelled
craft using a large USAF IR laser, which amount to essentially
all the actual flight test experience to date with externally
powered rockets in an atmsophere.

Other experts in similar areas include Jordin Kare, who is
focused on laser propulsion.


-george william herbert

wrote:
[...]while producing gigawatts economically is well understood,
it costs over a dollar a watt[...]

It does? Then how to account for this 40 kW generator for US$13k (which
comes to ~US$0.33/watt):
http://www.elitegenerators.com/40qumo50.html

Or these (one of which comes to ~US$0.15/watt):
http://www.electricgeneratorstore.com/sppa.html

Granted, a natural gas gigawatt electric power plant may indeed cost ~US$1,
but clearly it doesn't have to if it isn't intended to link into a utility
power grid and meet all the other requirements of said grid connection.

Perhaps the Isp of existing LH-Lox engines could be boosted by simply
irradiating them from behind with a microwave beam. The nozzle could
act as a focusing and receiving device and the water vapor in the
exhaust would absorb some beam energy further improving the Isp of
the rocket. The exhaust temperature could exceed conventional
limitations because the center would be heated much more then the
walls.

Who cares what the energy costs?

Zoltan

Hydrogen is a great fuel, and so are hydrocarbons.

Gaseous hydrogen and gaseous oxygen can be entrained in a spongelike
hydrocarbon aerogel and create a mixture less dense than air!
By controlling the relative ratio of hydrogen and hydrocarbon gel
density can be controlled over a wide range.

So, imagine a very long pipe that is equipped to manufacture aerogels
that entrain gaseous hydrogen/oxygen mixtures.

Imagine too the pipe varies the density of the aerogel/propellant
string so that the string comes to rest at various altitudes - causing
the string to trace out a synergic boost curve optimal to attain LEO.

Now, we create a boost vehicle with a ramjet annulus. It boosts off
the launch pad achieves supersonic flight and flies into the end of the
string. The vehicle ingests the aerogel propellant string - detonates
it - and derives thrust from it - tracking the string as it rises.

In the end we have a single stage vehicle attain orbit.

Once the first vehicle is on orbit, another string can be released and
rise to its given altitude - so every 15 minutes or so, we can launch
another payload into space by this technique.

http://www.aiaa.org/content.cfm?page...ort&gID=52 00
http://www.aiaa.org/content.cfm?page...aper&gID=21706
http://www.aiaa.org/content.cfm?page...97&g ID=23768

This is one way.

Another is to use laser energy to to ablate propellant from a solid
block of plastic, and then use laser energy again to detonate that
plastic into CO2 and H2O - creating a controlled blast of thrust. By
creating millions of points of thrust across a surface any sort of
lifting and control force can be applied to that surface.

http://www.aiaa.org/content.cfm?pageid=406

This is another way

So, imagine a very long pipe that is equipped to manufacture aerogels
that entrain gaseous hydrogen/oxygen mixtures.



Boy, you had better hope you don't get a electrostatic discharge inside
that string, or it's going to go off like a super-sized length of
primacord. :-)

Imagine too the pipe varies the density of the aerogel/propellant
string so that the string comes to rest at various altitudes - causing
the string to trace out a synergic boost curve optimal to attain LEO.

Now, we create a boost vehicle with a ramjet annulus. It boosts off
the launch pad achieves supersonic flight and flies into the end of the
string. The vehicle ingests the aerogel propellant string - detonates
it - and derives thrust from it - tracking the string as it rises.



That's somewhat similar to this idea:
http://www.desertsecrets.com/i.chemtrail1.jpg
http://www.desertsecrets.com/5,224,663.txt
A real problem would be that the propellent string could be distorted by
high altitude winds into a shape that the aircraft ingesting it would
have a difficult time following.
Here's what happened to the smoke trail from a Minuteman missile in
fairly short order due to winds at altitude:
http://www.freqofnature.com/photos/mmiii/P9192028.jpg
That's from this page BTW: http://www.freqofnature.com/photos/mmiii/

Pat

In article . com,
"William Mook" wrote:

Gaseous hydrogen and gaseous oxygen can be entrained in a spongelike
hydrocarbon aerogel and create a mixture less dense than air!

And here I've been giving my kids helium balloons that last only a week
or two. Where can I get some of this lighter-than-air aerogel?

,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| http://www.macwebdir.com |
`------------------------------------------------------------------'

zoltan wrote:

Has anybody investiassuminguse of microwave beamed powkineticca way of
eliminating the first stage of a rocket?


The Powers are just HUGE. One SSME, assuming 100% energy conversion to
kinetic energy of the exhaust is about 5GW . Thats 15 GW for the space
shuttle. In practice you will need a lot more than this.

This is Massive. Producting that kinda power in microwaves has only been
done on paper and the reality is that its unlikely to scale up as nicely as
you mite like.

Bottom line. Chemical rockets are not as bad as you mite think.

Greg

Pat Flannery wrote:

Here's what happened to the smoke trail from a Minuteman missile in
fairly short order due to winds at altitude:
http://www.freqofnature.com/photos/mmiii/P9192028.jpg
That's from this page BTW: http://www.freqofnature.com/photos/mmiii/

That is some pretty fireworks show. Some pretty expensive fireworks
show.

Joe Strout wrote:
In article . com,
"William Mook" wrote:

Gaseous hydrogen and gaseous oxygen can be entrained in a spongelike
hydrocarbon aerogel and create a mixture less dense than air!

And here I've been giving my kids helium balloons that last only a week
or two. Where can I get some of this lighter-than-air aerogel?

,------------------------------------------------------------------.
| Joseph J. Strout Check out the Mac Web Directory: |
| http://www.macwebdir.com |
`------------------------------------------------------------------'

lighter-than-air aerogel? sounds like a good material to build aircraft
from but it could become a very difficult to clean up form of litter. I
wonder how pieces of it might affect jet engines or how it might feel
on a windy day to have to dodge chunks of the stuff.
Ken