SR-71's sucessor

From: Peter Kemp peter_n_kempathotmaildotcom@

On or about Sun, 21 Dec 2003 17:04:23 -0800, "Tarver Engineering"
allegedly uttered:


"Wayne Allen" wrote in message
...

"Gene Storey" wrote in message
news:B0qFb.3428$6l1.2442@okepread03...

You may not be aware, but most recce sats are nuclear powered, and the
fuel to scoot them around does not have to be combustible.

I think your mixing two different power needs. If the birds are
carrying nuclear powered
energy cells that's simply for the electrical circuits. To move a
satellite requires propellant
(and it had better NOT be combustible) that once used cannot be renewed.

An electric plasma engine can address your issue of electric propulsion. A
teflon electric engine can fire many times.

You still need reaction mass, no matter how you're moving the vehicle
(unless you've got the mystical gravity drive).

---
Peter Kemp

Peter, you know tarver is going to explain
how he meant electron acceleration derived from the plutonium reactor. Never
mind the heat generated if you managed to get enough thrust to do anything
important would fry the systems in the satellite.

Dan, U.S. Air Force, retired

"Ugly Bob" wrote in message
...

"Fred the Red Shirt" wrote in message
om...
I do not know of any nuclear power _propulsion_ systems in present
use. Even if there were, it would still have to throw something
away from the vehicle to get momentum which means eventually it
woudl run out of whatever it was throwing away.

Except, possibly, solar electric propulsion.


http://www.qrg.northwestern.edu/proj...zoom-solar-ion.
html


Fred is right, no matter what process you use to excel the propellant
once the fuel is
gone its gone. Big paperweight floating around in space doing nothing.
Read the url you
provided and look up how the ion drive works, still needs a propellant - and
since any
craft has to be of a fixed size you have a fixed amount of fuel. Once its
gone it doesn't
matter if you use compressed gases or liquid fuels or itty bitty electrons -
its gone.

"Peter Kemp" peter_n_kempathotmaildotcom@ wrote in message
...
On or about Sun, 21 Dec 2003 17:04:23 -0800, "Tarver Engineering"
allegedly uttered:


"Wayne Allen" wrote in message
...

"Gene Storey" wrote in message
news:B0qFb.3428$6l1.2442@okepread03...

You may not be aware, but most recce sats are nuclear powered, and
the
fuel to scoot them around does not have to be combustible.

I think your mixing two different power needs. If the birds are
carrying nuclear powered
energy cells that's simply for the electrical circuits. To move a
satellite requires propellant
(and it had better NOT be combustible) that once used cannot be
renewed.

An electric plasma engine can address your issue of electric propulsion.
A
teflon electric engine can fire many times.

You still need reaction mass, no matter how you're moving the vehicle
(unless you've got the mystical gravity drive).

The teflon becomes the reaction mass.

(Wayne Allen) wrote in message ...
"Ugly Bob" wrote in message
...

"Fred the Red Shirt" wrote in message
om...
I do not know of any nuclear power _propulsion_ systems in present
use. Even if there were, it would still have to throw something
away from the vehicle to get momentum which means eventually it
woudl run out of whatever it was throwing away.

Except, possibly, solar electric propulsion.


http://www.qrg.northwestern.edu/proj...zoom-solar-ion.
html

I suppose solar anything is a subset of nuclear propulsion but the
comments below are entirely accurate.



Fred is right, no matter what process you use to excel the propellant
once the fuel is
gone its gone. Big paperweight floating around in space doing nothing.
Read the url you
provided and look up how the ion drive works, still needs a propellant - and
since any
craft has to be of a fixed size you have a fixed amount of fuel. Once its
gone it doesn't
matter if you use compressed gases or liquid fuels or itty bitty electrons -
its gone.


But there is one alternative that does not have that limitiation--
solar sailing. Solar sailing relies on the momentum transfer from
sunlight, deflected off of movable panels of some sort. No mass
is expelled from the vehicle. (At least not on purpose.)

--

FF

"Fred the Red Shirt" wrote

But there is one alternative that does not have that limitiation--
solar sailing. Solar sailing relies on the momentum transfer from
sunlight, deflected off of movable panels of some sort. No mass
is expelled from the vehicle. (At least not on purpose.)

Probably not fast enough for intel sats :-)

"Gene Storey" wrote in message news:YUOFb.4220$6l1.998@okepread03...
"Fred the Red Shirt" wrote

But there is one alternative that does not have that limitiation--
solar sailing. Solar sailing relies on the momentum transfer from
sunlight, deflected off of movable panels of some sort. No mass
is expelled from the vehicle. (At least not on purpose.)

Probably not fast enough for intel sats :-)

I'm doubtful that intel sats are manouvered on a target by
target basis. They would burn way way too much fuel and thus
be very short-lived.

--

FF

In message -
(Wayne Allen) writes:


"Ugly Bob" wrote in message
...

"Fred the Red Shirt" wrote in message
om...
I do not know of any nuclear power _propulsion_ systems in present
use. Even if there were, it would still have to throw something
away from the vehicle to get momentum which means eventually it
woudl run out of whatever it was throwing away.

Except, possibly, solar electric propulsion.


http://www.qrg.northwestern.edu/proj...zoom-solar-ion.
html


Fred is right, no matter what process you use to excel the propellant
once the fuel is
gone its gone. Big paperweight floating around in space doing nothing.
Read the url you
provided and look up how the ion drive works, still needs a propellant - and
since any
craft has to be of a fixed size you have a fixed amount of fuel. Once its
gone it doesn't
matter if you use compressed gases or liquid fuels or itty bitty electrons -
its gone.




Although it's correct that ion propilsion uses MUCH less fuel to produce the
same impulse (higher exaust speed), the thrust is tiny. For example,
the "Deep Space 1" craft had ion propulsion thrust of about 9 grams
and todays thrusters are no more than few tens of % better. Try calculating,
how long will it take to change the orbit by, say, 10 deg using ion
thruster. Without calculating I would guess order of months - too late for
most wars. You can use another way of thought: had nuclear-electric
propilsion be CAPABLE to supply significant impulse in reasonable time,
we would have spacecrafts with such propulsion traveling the bredth and
width of our solar system carrying people and cargo for reasonable cost.
Since it isn't going to happen with current combination of power sources
and electric propulsion, that's another proof of what electric propulsion
can't do.


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NOTE: before replying, leave only letters in my domain-name. Sorry, SPAM trap.
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Probably not fast enough for intel sats :-)

I'm doubtful that intel sats are manouvered on a target by
target basis. They would burn way way too much fuel and thus
be very short-lived.


Usually not, though for a few really important taskings, the mission
planner guys are willing to expend quite a bit of fuel to get
coverage. Usually, they won't do plane changes (those are REALLY
fuel-expensive and wouldn't provide much difference), but fairly
drastic changes in apogee/perigee heights are more common. They can
even drop below 100km if really necessary, though only for a couple
orbits (any more and the satellite would decay).

Current US recon satellites are solar- and battery-powered, with
hypergolic fuels. The current optical recon series uses the same
basic frame as the Hubble telescope (though the Hubble doesn't have
any fuel, and its optical system is different).

In article , Peter Kemp
peter_n_kempathotmaildotcom@ says...
On or about Sun, 21 Dec 2003 17:04:23 -0800, "Tarver Engineering"
allegedly uttered:


"Wayne Allen" wrote in message
...

"Gene Storey" wrote in message
news:B0qFb.3428$6l1.2442@okepread03...

You may not be aware, but most recce sats are nuclear powered, and the
fuel to scoot them around does not have to be combustible.

I think your mixing two different power needs. If the birds are
carrying nuclear powered
energy cells that's simply for the electrical circuits. To move a
satellite requires propellant
(and it had better NOT be combustible) that once used cannot be renewed.

An electric plasma engine can address your issue of electric propulsion. A
teflon electric engine can fire many times.

You still need reaction mass, no matter how you're moving the vehicle
(unless you've got the mystical gravity drive).

Damn it Peter, now you've gone an done it.

Just wait patiently by the door for the men in black suits...


--
When dealing with propaganda terminology one sometimes always speaks in
variable absolutes. This is not to be mistaken for an unbiased slant.

In article , says...

"Peter Kemp" peter_n_kempathotmaildotcom@ wrote in message
...
On or about Sun, 21 Dec 2003 17:04:23 -0800, "Tarver Engineering"
allegedly uttered:


"Wayne Allen" wrote in message
...

"Gene Storey" wrote in message
news:B0qFb.3428$6l1.2442@okepread03...

You may not be aware, but most recce sats are nuclear powered, and
the
fuel to scoot them around does not have to be combustible.

I think your mixing two different power needs. If the birds are
carrying nuclear powered
energy cells that's simply for the electrical circuits. To move a
satellite requires propellant
(and it had better NOT be combustible) that once used cannot be
renewed.

An electric plasma engine can address your issue of electric propulsion.
A
teflon electric engine can fire many times.

You still need reaction mass, no matter how you're moving the vehicle
(unless you've got the mystical gravity drive).

The teflon becomes the reaction mass.


Didn't know there was great amounts of teflon floating around in space....


--
When dealing with propaganda terminology one sometimes always speaks in
variable absolutes. This is not to be mistaken for an unbiased slant.