The Next Lunar Landing - BOTE with NOX/HTPB

Peter Stickney wrote:


Tom-Tom was a horse of a different color. It grew out of studies by
Dr. Richard Vogt, formerly of Blohm & Voss, that indicated that
extending the span of an aircraft by attaching flexibly-hinged,
free-floating sections to the tips would increase its cruise
efficiency. It was only a short leap to decide that the free-floating
tips could just as easily be other aircraft. He sold sonefolks at
Wright-Pat on the idea, and Tip-Tow and Tom-Tom were born.


North American and Boeing tried to sell SAC on a B-70 type bomber (in
the first WS-110 competition) that used giant winged jettisonable tanks
on the wingtips to get the desired range; Curtis LeMay took one look at
the designs and told them to go straight to hell: "Back to the drawing
boards. Those aren't airplanes- they're three-ship formations!"

(Vogt, BTW, is a favorite of the Luft '46 folks - the ones who believe
that the Germans invented the 21st (or is it the 24th & 1/2 Centuries
in the last months of WW2, and wrote it all down on Bierstube napkins
before the fall of the 12 Year Reich. This is a good example of what
doesn't get taken into account - the concept is theooretically O.K.,
but making itwork is a gold-plated S.O.B., and better systems (Such as
U-2s, and Flying Boom-type refuelling) are easier to develop.

Blohm and Voss was a ship building firm that decided to get into the
aircraft business by building flying boats; they managed to build a
flying boat every bit as attractive as a tramp steamer:
http://www.bdli.de/geschichte/zivile...sHa139-400.jpg
Later they would make another flying boat that was about as attractive
as a tramp steamer...and about the size of one also:
http://www.lietadla.com/lietadla/nem...-238/bv238.jpg
Their unpowered glider missile with the cast-concrete wings was a novel
approach to aerodynamic finesse: http://www.luft46.com/jhart/jh204-3.jpg
"But wait" you will say "What exactly is that missile with the
cast-concrete wings dropping off of? It doesn't look like it's drawn
right..." Oh, no... it's drawn right...it just isn't _designed_ right;
the Vogt magic is upon it, and clings to it like a lamprey, slowly
sucking its vitality from it.
And now for a quick trip to the Vogt Madhouse; or how not to design
rational aircraft in nine easy steps- don't look at any of these for any
too long; their unwholesome geometry belongs more in the the works of
H.P. Lovecraft than in the annals of aviation- it's easy to imagine
Cthulhu hopping out of one of these at R’lyeh Aerodrome:

http://www.airventure.de/historypics/bv_141.jpg
.....to give the observer a better view.

http://www.luft46.com/bv/bvp170.html
....to confuse RAF Seafire pilots into thinking that they are suffering
from hypoxia?

http://www.luft46.com/bv/bvp111.html
.....Crimson Skies, anyone?

http://www.luft46.com/bv/bvp163.html
....for pilots and aircrew who can't stand the sight of one another?

http://www.luft46.com/bv/bvp192.html
....propellor in front....or propellor in the back? Hey, I've got it!

http://www.luft46.com/bv/bvp202.html
....someday a major government agency of some distant nation will think
this is absolutely brilliant!

http://www.luft46.com/bv/bvae607.html
.....okay, so the visibility during taxiing is going to be a bit less
than optimal.

http://www.luft46.com/bv/bvrmist.html
So the pilot pulls 20 G's on seperation....isn't it just plain cool though?
What do you mean "why?", is that all you can think of, you pathetic
small-minded fool?!

And last, but certainly not least- what a Messerschmitt Bf-109 looked
like after Blohm & Voss made a few "minor" modifications to it to suit
to high altitude flight:
http://www.luftarchiv.de/flugzeuge/blohm-voss/bv155.htm
Unfortunately, this hideous thing still exists...the Smithsonian
Airspace Museum has it.... and you thought that the Hope Diamond was the
only cursed thing that the Smithsonian had:
http://www.aircraftresourcecenter.co...55/walk235.htm
I've got a model of this abomination... words can't do it justice...or
injustice actually; picture a crop duster designed for use at Martian
atmospheric pressures- to wipe out outbreaks of The Red Weed, no doubt.
Hopefully by crashing on them.

Pat

Pat Flannery wrote:


http://www.luft46.com/bv/bvp170.html
...to confuse RAF Seafire pilots into thinking that they are suffering
from hypoxia?

http://www.luft46.com/bv/bvp111.html
....Crimson Skies, anyone?

Got those two backwards- the Vogt curse is at work! Nothing shall be in
its rational form!
(Hound Of Tin & Dalos jumps out of the corner of the room; with three
legs on one side, and one on the other.) :-D

Pat

On Fri, 22 Oct 2004 02:55:54 -0500, Pat Flannery wrote:

http://www.luft46.com/bv/bvp192.html
...propellor in front....or propellor in the back? Hey, I've got it!

That kinda looked familiar, so I dug through some old magazines.
This idea was featured in the August 1943 issue of "Air Progress"
(with a cover story on the debut of Sikorsky's first practical helicopter-
the inventor at the controls).

This doesn't suffer from the uglies quite like the B und V planes, but it does
do them one better by having counter-rotating props!

1st page-
http://www.dohyo.com/shipboardfighter1.jpg

2nd page (three-view)-
http://www.dohyo.com/shipboardfighter2.jpg

Dale

Pat Flannery wrote:



Blohm and Voss was a ship building firm that decided to get into the
aircraft business by building flying boats; they managed to build a
flying boat every bit as attractive as a tramp steamer:
http://www.bdli.de/geschichte/zivile...sHa139-400.jpg
Later they would make another flying boat that was about as attractive
as a tramp steamer...and about the size of one also:
http://www.lietadla.com/lietadla/nem...-238/bv238.jpg
Their unpowered glider missile with the cast-concrete wings was a novel
approach to aerodynamic finesse: http://www.luft46.com/jhart/jh204-3.jpg
"But wait" you will say "What exactly is that missile with the
cast-concrete wings dropping off of? It doesn't look like it's drawn
right..." Oh, no... it's drawn right...it just isn't _designed_ right;
the Vogt magic is upon it, and clings to it like a lamprey, slowly
sucking its vitality from it.
And now for a quick trip to the Vogt Madhouse; or how not to design
rational aircraft in nine easy steps- don't look at any of these for any
too long; their unwholesome geometry belongs more in the the works of
H.P. Lovecraft than in the annals of aviation- it's easy to imagine
Cthulhu hopping out of one of these at R’lyeh Aerodrome:

This should have come with a keyboard-integraity alert! Fortunately
experience has shown that I can only allow topped containers
with straws near the machines, saving me - this time.

One suspects Vogt might have had much better vision on one side.

Bill Keel

"Dale" wrote in message
...
On Fri, 22 Oct 2004 02:55:54 -0500, Pat Flannery
wrote:

http://www.luft46.com/bv/bvp192.html
...propellor in front....or propellor in the back? Hey, I've got it!

That kinda looked familiar, so I dug through some old magazines.
This idea was featured in the August 1943 issue of "Air Progress"
(with a cover story on the debut of Sikorsky's first practical helicopter-
the inventor at the controls).

This doesn't suffer from the uglies quite like the B und V planes, but it
does
do them one better by having counter-rotating props!

Gee, Dion was a multi-talented kinda artist huh? He got into rock-n-roll
later on y'know.

Dale wrote:

That kinda looked familiar, so I dug through some old magazines.
This idea was featured in the August 1943 issue of "Air Progress"
(with a cover story on the debut of Sikorsky's first practical helicopter-
the inventor at the controls).

This doesn't suffer from the uglies quite like the B und V planes, but it does
do them one better by having counter-rotating props!


Those are hilarious looking! I really like the bulged belly with Grumman
"Wildcat" style gear housing.
And as the shade of Dr. Vogt looks down from his asymmetrical cloud,
someone else is looking up:
http://www.longeze.com/The_Design/Bu...an/Catbird.jpg =-O

Pat

William C. Keel wrote:


One suspects Vogt might have had much better vision on one side.



Astigmatism would explain a lot wouldn't it?
A lot of the former German aircraft designers that we brought over had
real artistry- unfortunately Dr. Vogt was the Salvador Dali of the group.

Pat

"Pat Flannery" wrote in message
...

And as the shade of Dr. Vogt looks down from his asymmetrical cloud,
someone else is looking up:
http://www.longeze.com/The_Design/Bu...an/Catbird.jpg =-O

Geez, he really stood on the shoulders of a giant with that one!

(AA Institute) wrote in message . com...
(william mook) wrote in message
sinp

Since you are insisting and as I now have a bit more time to hand, let
me elaborate upon my points to a finer level of detail for the benefit
of your understanding.

Conceptually it sounds a good idea -

Um, its not my idea, I was responding to another person's idea,
analyzing it.

I didn't say this was your idea, I am talking here about professor
Winglee's magnetic plasma sail propulsion concept as depicted in this
article:-

http://www.spaceflightnow.com/news/n...arspropulsion/

Right.


My only contribution you snipped.

Sorry... I was in a hurry and only wanted to put some quick opinions
forth on professor Winglee's article, which was "breaking news" on the
day.

Okay

If the suborbital rocket is a laser light craft

http://www.lightcrafttechnologies.com/technology.html

This light craft business of lifting things from the ground all the
way up to orbital height, just doesn't sound too promising to me (I'm
just handwaving here... what I do best!). If you or anyone else
believes in this concept, I'd hope you could fill me in on the hard
evidence that supports advancing light craft technology?

Pretty straighforward. You use laser energy to heat a working fluid
and eject that working fluid creating a rocket. Kantrowitz, Kare, and
others have published peer reviewed articles at length and research
has been completed.

http://pakhomov.uah.edu/Minigrant.pdf
http://gltrs.grc.nasa.gov/reports/20...000-210240.pdf
http://www.riken.go.jp/lab-www/libra..._50/50_011.pdf
http://146.229.208.56/ISBEP_1/Program.html
http://www.wws.princeton.edu/cgi-bin...003/900307.PDF

Models have been flown;

http://science.howstuffworks.com/light-propulsion1.htm

The exhaust velocity possible with certain forms of this process -
laser sustained detonation - is 110 km/sec. This means that to attain
escape velocity you need something like;

u = 1 - 1/EXP(11/110) = 0.0951

propellant fraction.

The power needed to sustain each kg of thrust is;

P = 1/2 * mdot * 110,000^2
F = mdot * 110,000

So, re-arranging the second equation;

mdot = F/110,000

and plugging it into the first equation;

P = 1/2 * F/110,000 * 110,000 ^2
= 1/2 * F * 110,000
= 55,000 * F

Where F is in Newtons, so, to convert to kg;

P = 5,600 * F(kg)

So, each kg of thrust requires 5.6 kW of energy appear in the 110
km/sec jet. If the overall efficiency is around 2,then you'll need 10
kW of laser energy for every kg of thrust. So, 100,000 kg of thrust
requires a laser that has a continuous output of 1 billion watts. A
laser that's 20% efficient will require a 5 billion watt power plant!

Of course a 100 ton thrust would lift something like 77 tons GLOW,and
this would project 70 tons to escape velocity.

if it can be worked. I think most
people have already raised the 'action = reaction' dilemma, where

Here you've lost me. Right off the bat. I don't know what you're
talking about.

Newton's third law.

Yeah, m1 * V1 = m2 * V2, I understand that. But I don't know what
you're getting at.


When the emitting plasma station exerts a force on
the mag-sail to drive it forward, the emitting plasma station itself
will experience a motion in the opposite direction,

Yep.

so how will it
keep its beam continuously firing at the mag-sail vehicle without
getting misaligned and needing constant realignment via additional
fuel and thrusters?

Well that's an understandable question. It depends on the mass
difference between one and the other. If the mass of the station is
the entire Earth or some other celestial body, then the change in
speed is trivial compared to the change of speed of the vehicle.

If the mass of the station with its power plants and plasma is vastly
larger than the vehicles is supports, then changes of speed are small.

Since the station must point toward the vehicle which is changing
direction, the station's velocity increment may not be in a steady
direction reducing the total action.

Since the station may drive several vehicles at once in different
parts of the sky, the station's velocity increment may be reduced.

A high speed plasma accelerated in a direction opposite the plasma
intended to drive a vehicle would cancel the action of the driving
plasma entirely.

The effects of the emission can be calculated, measured, and accounted
for by the firing computer. Note that missiles routinely hit their
targets over vast distances despite coriolis forces and such. Future
computers controlling the firing and tracking of a plasma beam would
be as good and most likely better.

Even if the emitting plasma station at LEO pushing the vehicle outward
from Earth is somehow stabilised, how will the *opposite* braking
plasma station at the destination planet be stabilised?

If the station is 10,000x more massive than the vehicle then the
action of the plasma stream will impart 1/10,000th the speed. So, if
the vehicle is accelerated to 20 km/sec then the station will be
accelerated by 2 meters per second (4.4 mph). This is easily
accounted for in the firing computer, and if it becomes a problem it
can easily be corrected with rockets that fire in the opposite
direction.

What happens
when *its* stabilising fuels run dry?

It gets replenished.

Surely the costs of re-fuelling
a station orbiting a remote planet would be mega?

Depends on the details. What happens when the plasma source runs dry?
What happens when the thing has to be brought back for servicing?

If the station is designed for a specific mission sufficient plasma
material and sufficient power and sufficient control propellant will
be put on board at the outset to complete the mission. The vehicle
may then be replenished with a supply rocket similar to the rocket
that put it wherever it found itself operating if that were needed.



Robert Winglee is a NASA scientist who is trying to scope out what it
might take to build a magnetic sail to ride the solar wind. Creating
our own directed pulses of plasma to allow such a sail to outperform
the solar wind is feasible once such a sail is operational. To date,
I have seen nothing but a lot of handwaving.

Your statement, in context of this data is meaningless to me.

Let me explain the basic workings of this THING as I understand it. In
this concept that Winglee is working on, an electronically excited
stream of plasma ions (which have a measurable mass - as opposed to no
mass at all in the case of photons of light) is emitted from a
transmitting station which will push an interplanetary vehicle from
Earth orbit to the orbit around a destination planet, e.g. Mars. The
plasma ions are fired from a gun in Earth orbit to impact upon an
invisible, but electro-magnetically inflated, sail that is deployed
around an interplanetary spacecraft which is also carrying a light
weight *payload*. The plasma beam hits the electro-magnetic sail
deployed around the spacecraft and exerts a force ("thrust") on the
sail, which pushes the spacecraft forward. Accumulation of thrust from
continuous plasma beam firing over time accelerates the spacecraft
toward its target planetary destination. Before it reaches that
destination, another gun stationed in orbit around the destination
planet then fires an identical beam onto the spacecraft's magnetic
sail from the opposite direction which slows it down to enable either
a gentle glide into orbit around or descent down into the destination
planet's atmosphere.

Yep. This wasn't the source of my confusion.

As I understand it, the magnetic plasma sail propulsion concept is
strictly an *in space* concept that has no bearing on how payloads are
transported up from Earth's surface to LEO or how they make their way
down onto the surface of the destination planet.

Okay. This is a more reasonable question. Its answer has to do with
thrust to weight. That's why I proposed combining laser propulsion
with this concept. Especially if the plasma beam can be collimated
accurately - as in the idea of a self-contained smoke ring.

Its operational
limits are strictly 'orbit to orbit', as I mentioned in my earlier
post. That's where I was saying that Mars Rover style aeroshell
packaging and airbags and parachutes could be used for the entry,
descent and landing from Mars orbit down to its surface.

What's the thrust to weight proposed?

Again T/W depends on the details. Thrust is related to power and
exhaust speed as shown above. Thrust to weight depends on the size of
the plasma reflector is areal density and so forth. If reflector mass
is large and plasma densityh low then thrust to weight will be low.
If the reflector is small, thrust to weight might be high.

Are you with me so far?

Sure - now that you've explained yourself. Your earlier statements
were unintelligeble to me. These statements make more sense. I won't
comment on whether they're consistent with your earlier statements.

I see one immediate benefit in a manned Mars mission where *fast*,
straight-line transfers of small loads are required from Earth=Mars
(orbit to orbit), without having to rely on long time windows dictated
by Hohmann transfers.

Again, I don't understand this. You're implying small loads, and
straight lines and claiming a benefit. Then, you tack on a sentence
about Hohmann transfers. It don't make any sense son.

You've got minimum energy transfer orbits, which is the lower limit of
performance for interplanetary flight. You've got high-speed transfer
orbits, that are still elliptical. You've got parabolic orbits that
are faster still. You've got hyperbolic orbits even faster yet.
Heck, even light beams bend, and at the solar surface that's 2 G Ms
/(Rs c^2) = 4.2 x 10^-6 radians = 0.87 arc sec, as shown by Einstein
(Annalen der Physik vol.35, p.398) in 1911 and nothing is known to
travel faster than light!

So, your straight line comment is right out the window. The words
that follow it don't have any logical connection to it as far as I can
tell.

A "Hohmann least energy co-tangential transfer orbit" is the standard,
conventional method by which an interplanetary spacecraft achieves a
low fuel flight from Earth to a destination planet.

Its standard for chemical boosters I guess, that's because they're
minimum energy - and you're energy constrained with chemical boosters,
see? That wasn't the source of my confusion as my reply clearly
shows.

That method of
Earth = Mars transfer typically takes 6 to 8 months, since the
Hohmann ellipse is a *curved* heliocentric trajectory going half way
around the Sun to reach Mars.

It always comes around 180 degrees around the sun from where it
departs - this is a consequence of it being the lowest energy orbit to
get from one planet to another.

It has as its perihelion point where the
Earth is at launch and its aphelion as the point where Mars is at
arrival.

This is absolutely true. It has nothing to do with the confusing part
of your statement - and I think you know this.

This is standard textbook stuff

That's right.

we've been using since the
60s,

Yes.

you can easily re-familiarise yourself with this if need.

Why? I clearly know this better than you. That's not the source of
my confusion. The source of my confusion was the foolish statement
you made about straight line trajectories being a benefit somehow.
The clearly said there were no such things as straight line
interplanetary trajectories. There are hohmann minimum energy
trajectories, there are elliptical trajectories, where the vehicle
flies slower than the solar escape, there are parabolic trajectories
where the vehicle flies at solar escape velocity and there are
hyperbolic trajectories, where the vehicle flies at faster than solar
escape velocity - I even pointed out that light beams are curved by
solar gravity. I CLEARLY STATED THIS - you absolutely did not address
it in anything you've said above. Plainly your goal here is merely a
foolish attempt to cover your ignorance by repeating things you know -
while not addressing my points at all.

With professor Winglee's magnetic plasma sail propulsion, he is
proposing to bypass that Hohmann long winded elliptical trajectory
business

I know this. But you said there was some sort of benefit in straight
line trajectories, and these sorts of trajectories do not exist except
in the case where you fly radially from the sun from one planet to
another. But this would rarely if ever be done since it requires that
you wait just as long between flights as a minimum energy (Hohmann)
orbit and really wastes a lot of the benefit associated with higher
transfer speeds.

and going for a "straight line" crossing when the Earth
overtakes Mars in its orbit every 780 days (the 'synodic period')
around *opposition* time. 48 million miles is the average minimum
Earth-Mars distance during such close approaches between the two
planets

Yes, there is one special case where you travel radially from the sun,
your trajectory will be straight. Very clever. But that flies in the
face of the fact that you said you can avoid flight windows associated
with minimum energy transfers. That was the benefit of straight line
orbits according to your original comment. I didn't understand it
because it didn't make sense. Your clarification here makes even less
sense. That's because you weren't talking about straight line
trajectories even though you said straight line, you were taling about
high-speed hyperbolic trajectories.

Again, since, flights along radials from the sun between planets
depend on the synodic periods every bit as much as Hohmann orbits. To
fly radially from the sun to another planet requires that you wait
synodic periods just as you do with minimum energy orbits - as you
point out - between launchings. THIS flies in the face of the fact
that you said you could avoid these.

So, both cannot be true. That's quite clear to everyone.


in their respective orbits. Winglee projects speeds of 26,000
miles per hour = 625,000 miles per day for the magnetic plasma sail
spacecraft. At that speed, a mag-sail spacecraft will zip *straight*
across to Mars in 76 days around the *opposition* time between Earth
and Mars. There is not much room here for a curved trajectory in the
Hohmann sense,

A hyperbolic trajectory will provide for very short flight times
between worlds. No question there. That's not what you said. You
said straight line and I found that confusing because it didn't make
any sense given my knowledge of orbital types.

especially if the *round trip* time is to be further
shortened to just 90 days, as stipulated in the news article:-

Well, a 90 day hyperbolic trajectory is not a straight line as you
said. Its not a radial trajectory. Its a hyperbolic trajectory. Its
a trajectory that can be flown nearly any time throughout the synodic
period.

If you meant to say hyperbolic trajectory and mis-stated it as a
straight line, why not say so? That's a much more respectable
response than trotting out radial trajectories which are as
constrained as minimum energy orbits, with fewer benefits.

But, even that still doesn't make sense in the context of your earlier
statement of using aeroshells to enter the Mars atmosphere with,
because your approach velocity is very very high for 90 day transit
time hyperbolic trajectories.

http://www.spaceflightnow.com/news/n...arspropulsion/

I've read the articles, that's not the source of my confusion. The
source of my confusion are your ignorant and contradictory statements
about straight line trajectories and atmospheric braking.

Look, I can see how you might think of a high-speed hyperbolic
trajectory as 'straight' okay, but accept that they're not. That's
all.

But then, ask yourself, what's the entry speed of such a trajectory at
mars without braking? Too high for aerodynamic braking to be very
effective. See?

So, it didn't make any sense to me no matter how I put it together.
You take my comment about being confused totally out of context and
explain to me things I know better than you which is just plain stupid
on your part. And everyone reading this knows it.

This is an example of a benefit that I see if you want to transport
equipment across at *speed* ahead of sending human expedition crews to
the surface of the Red Planet.

It all depends on cost. But generally yes, if you have a low-cost
means to propel things to Mars, or any planet, you can send unpiloted
one way supply missoins to build up needed equipment and supplies.
Depending on the details.

This might be necessary if you want to
build up substantial amounts of infrastructure very quickly.

If you're waiting 780 days between flights, as you indicated above, in
an effort to avoid telling me you meant hyperbolic trajectories - then
you're not going to do things quickly, no matter how short the transit
times.

Okay, if
the propulsion is ultimately proven to be 100% viable and *safe* for
humans to travel on a... small boat with its sails adapted to the
breezes of heaven... then sure, let the two way Earth = Mars
crossings be done using magnetic plasma sail propulsion on *manned*
vehicles, where the real benefits of fast transit times for astronauts
would most certainly start to be realised.

I haven't seen a real engineering analysis of plasma propulsion. I
don't think a beam can be usefully collimated over distances needed. I
do think it might be possible to swirl a plasma in a way to maintain
its size over longer distances than a constant beam - but I haven't
seen any mathematical analysis of this.


snip

But, again, you're changing gears! You began the conversation talking
about Mars, now you're talking about the moon! Heck, you don't need
high speeds to get to the moon. It only takes 3.5 days to get to the
moon along a lunar free return trajectory. That only takes 10.85
km/sec. If you could send plasma pulses across 1 million km, as you
need to do with interplanetary flight, you could send them to the moon
reliably. That means all you've gotta do is wait for the luar craft
to transit across the backside of the moon and be traveling toward
Earth, and then, slow it with your Earth based pulse -into lunar
orbit. Then, you could deorbit with conventional rockets. This gets
you stuff on the moon pretty cheaply.

Where I propose we use the LEO to Moon crossing for zipping small
loads back and forth is purely as a nearby *test bed* for evaluating
the magnetic plasma sail propulsion technology at minimal cost. Of
course the Earth = Moon transit times are very short and will
probably not make using magnetic plasma sail propulsion worthwhile
here.

Depends on the details. See, math is important and that makes it more
useful than handwaving.

Also LEO = Moon _means_ LEO to *lunar orbit*, where the plasma
generating station is in orbit around the Moon and powered solely
using solar panels (as is the one at LEO).

This is nonresponsive.


Now you can advise me on
the feasibility of using solar electricity for generating the
plasma... I don't understand the temperature requirements for
generating plasma beams... that part is over to you!

The plasma beam isn't the issue. The collimation of the plasma beam
over the required distances is. I think that's why WInglee proposes a
large magnetic sail.

I counter that just from first principles making plasma 'bullets' that
hold together through rotational motion of the plasma itself is likely
to result in a more collimated beam smaller magnetic sails, and higher
thrust to weight.

Further, if we use the Earth's upper atmosphere - that is already
plasma - tearing pieces of it away with EMP pulses to form our plasma
bullets, we don't need to orbit anything.

Finally, if you build a similar system on Mars, you can use it to a)
brake incoming high speed payloads and b) launch those payloads back
to Earth.



So what seems to be the delay?!

You're kidding right? Jesus, Winglee hasn't even fully characterized
what a magsail is let alone how to build one.

Let's wait until Winglee has completed his US$75,000 advanced
propulsion feasibility studies, and I'm sure NASA will publish his
results in 6 months time with all the *hard numbers* and *equations*
(as opposed to *handwaving*) on thrust versus load versus power versus
... whatever else.

I agree. So why the question? Why did you believe there is a delay?
Again, you've avoided the obvious.



Abdul Ahad

Where do you live friend?

How is that important?

Because I'm interested.

(william mook) wrote in message
snip

You have some good expertise here, clearly a man of knowledge! I shall
not hesitate to recommend you to NASA!

so how will it
keep its beam continuously firing at the mag-sail vehicle without
getting misaligned and needing constant realignment via additional
fuel and thrusters?

Well that's an understandable question. It depends on the mass
difference between one and the other. If the mass of the station is
the entire Earth or some other celestial body, then the change in
speed is trivial compared to the change of speed of the vehicle.

If the mass of the station with its power plants and plasma is vastly
larger than the vehicles is supports, then changes of speed are small.

Since the station must point toward the vehicle which is changing
direction, the station's velocity increment may not be in a steady
direction reducing the total action.

Since the station may drive several vehicles at once in different
parts of the sky, the station's velocity increment may be reduced.

A high speed plasma accelerated in a direction opposite the plasma
intended to drive a vehicle would cancel the action of the driving
plasma entirely.

The effects of the emission can be calculated, measured, and accounted
for by the firing computer. Note that missiles routinely hit their
targets over vast distances despite coriolis forces and such. Future
computers controlling the firing and tracking of a plasma beam would
be as good and most likely better.


That explanation now makes things much clearer for me. Thanks.


Where do you live friend?

How is that important?

Because I'm interested.

I live in the UK.

Now, I was wondering if you have much expertise or done much in the
way of analysis on the astrodynamics requirements of capturing an
asteroid into orbit around the Earth? See, I have this idea:-

http://uk.geocities.com/aa_spaceagen...arth-ring.html

When people like George W. Bush and other great space visionaries
of our time are offering us "Moon to Mars" initiatives... I'm offering
a "Celestial Titanic to all the Planets and Stars" initiative that's
much closer to home... yet it can take us infinitely farther out into
the cosmos!

Clearly much will depend on the choice of asteroid, its final mass
post-excavation, the geometry of its orbit and so forth. I'd like to
know (purely BOTE) if I propel the asteroid for a close fly-by of a
planet like Venus or Mars for "aerobraking" whether *that* would be my
best bet for capturing the beast into an initial orbit around the
Earth?

(That is *after* it's excavated in *its* heliocentric orbit where it
has lost 90% of its initial mass in the hollowing out process. Assume
the object is cylindrical of 3 km length x 1.5 km wide, density of 2.5
grams/cm^3)

Abdul Ahad