Subject: Re: tentative hybrid design.
From: [email-masked] (Kelly Starks x7066 MS 10-39)
To: "L. Parker" <[email-masked]>
Cc: [email-masked] (Kelly Starks x7066 MS 10-39)
Date: Mon, 4 Mar 1996 08:04:53 -0500

At 5:59 PM 3/1/96, L. Parker wrote:
>At 12:22 PM 3/1/96 -0500, you wrote:

>>At near light speed? Wouldn't it at least cause a flare? 

>Who was the SF author that coined the phrase "c-fractional missiles"? I
don't think even he (or she) quite envisioned THAT much mass at near light
speed! The venerable E.E. Doc Smith would have appreciated this one... 

>Lee Parker

Certainly not the most mild mannored way to enter a star system. 

;)

Kelly

===============================================

Date: Mon, 4 Mar 1996 08:30:44 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: interstellar drive group <[email-masked]>, David
<[email-masked]>, hous0042 <[email-masked]>,
KellySt <[email-masked]>, kgstar <[email-masked]>, lparker
<[email-masked]>, rddesign <[email-masked]>, Steve
VanDevender <[email-masked]>, "T.L.G.vanderLinden"
<[email-masked]>
Bcc: 
X-Attachments: 
At 4:57 PM 3/1/96, Brian Mansur wrote:
>>From Brian
>March 1, 1996

>Here it is: the detailed design I promised (as detailed as I can make it at
the moment anyway). But first: does the "interstellar drive group"
selection that I now see on my address book now account for everyone in
the discussion team? Okay, on with the show. 

>Note that this is my first draft. The lab is about to close and I have a lot
more ideas to cover but they may have to wait a bit. Things like sail
shielding and mirror array design are among them. Sill I'm going to send
what I've got to let you all have some fun ripping it apart :) 

>MARS HYBRID DESIGN II (Kevin already submitted the first this morning) 

>Total mission time: 50+ years
>Pathfinder(s) mission flight time: 40+ years Asimov flight time: 24+
years
>Asimov exploration phase time: Undetermined 

If its going to take 50 year to get there. I think people would put it off
until they could think up a faster ship. Or just lose interest in the project. 

>ASSUMPTIONS:
>It is assumed for this mission plan that a high degree of robotic
automation has already made possible the production of at least 1E18 W
needed to power 1E7 masers without much human supervision. It is also
assumed that this maser array is totally dedicated to the mission and that
the beam will be left throughout the mission. 

>PHASE 1: LAUNCH OF PATHFINDERS
>At least one heavy pathfider vessel will be sent before the Asimov using
maser sail to reach a terminal velocity of 1/3c. Pathfinder carries several
thousand, heavy duty, heavy weight, individually targetable, disassembled
mirror arrays that will be deployed roughly 30 years later near TC (see
reflectors in an upcoming posting). These arrays (probably making an
effective 1000 km+ wide reflector) will reflect maser energy back to the
Asimov for the deceleration phase. The Pathfinder may or may not have a
crew depending on the level of automation available at the time of launch. 
>Also, it may or may not carry emergency supplies for the Asimov should
they choose to match speed and dock during the deceleration phase. 

Are you assuming the beam would be tight enought to be reflected after 11
light years. Not to mention assuming a mirror could hit the ships sail with
the reflected beam, a few light years away? 

>PHASE 2: LAUNCH OF THE ASIMOV
>The Asimov is maser pushed to a high %c terminal velocity. It is hoped
that the maser propulsion system will be efficient enough to push the
Asimov to a speed at which the effects of time dialation will be useful to
the crew. At the very least, a max speed of .75c is assumed here. 
>This ship will consist of an ion drive for in system shuttling around TC.
It will also carry the exploration team and their supplies for the mission.
Among the supplies already mentioned in other discusions are seed robots.
They will be used to start a robot workforce that will help construct,
among other things, a precision mirror array to reflect the maser energy
from Sol back to the Asimov's maser sail when the exploration phase is
completed.

>PHASE 3: DECELERATION OF THE ASIMOV
>The exact process has many variations. If there are several Pathfinders,
each, the one closest to the Asimov will deploy its reflector array and
then move to a safe range from the beam path. The array will enter the
beam path and redirect the maser energy back to the Asimov. The Asimov,
of course, will have turned its sail around (a slow and delicate process). It
will also have moved slightly to the side the maser beam coming from Sol
to prevent blocking of the array. 

I assume 'array' refers to the reflectors on the pathfinders. 

If the Pathfinders are reflecting the beam off to one side. They will be
pushed out of the beam in the other direction, and accelerated forward.
Given that the beam presure is strong enough push the ships in the first
place, it would be to strong for the ships thrust against. 

>Some method of periodic or even continuous course correction on both the
Asimov's part and the array's will be required to correct for the angle at
which the maser beam must be reflected. The Asimov may simply angle its
sail slightly with the edge furtherest from the Sol to array beam tilted
back toward Sol. The array will have to use built in rockets, or else tilt
from time to time in the proper direction to allow vectorial force to push
it back into the center of the beam.

This might be complicated given the main sail would be curved like a
parachute, not flat. 

>Now, assuming that the doplar effect will cause problems with reflection
of the maser beam, another Pathfinder could deploy it's array and continue
the decelation process. Note that I don't know if the most efficient thing
that the Asimov can do with the redirected maser beam will be to simply
bounce it back to space or to power a ion drive. The exhaust from an ion
drive would make for nice shielding against large particles. 
>One final note. As the Asimov and Pathfinder speeds reach equilibrium
they have the option of docking (assuming the deceleration of the Asimov
brought it close to the Pathfinder when speed equilibrium was reached. At
this point, any crew on the Pathfinder could cross over. Note that the
Asimov could dock with only one Pathfinder. 

It could dock with more than one. But that wold depend on their speeds and
relative positions. 

>PHASE 4: SYSTEM EXPLORATION/CONSTRUCTION OF MASER REFLECTOR 
>The Asimov enters the Tau Ceti star system's Kupier Belt. At this point it
disassembles its sail and starts scouting for a low gravity, metal rich
Kupier body that is not too far from the maser beam path. Once such a body
is located, the seed robots are deployed to begin a robot community. 
>Since the Kupier body will be too far away from Tau Ceti for solar energy
collection, it is assumed that the robots will be powered by fusion reactor
that must be brought along (in addition to the fuel). Depending on the
automation technology at the time of launch, these robots will at least be
responsible for construction of a mirror platform needed for
reacceleration to Sol.

Why so far out? That doesn't sound like and area we'ld want to do most of
our exploring at. So why make the base there? 

You could fuel the fusion reactors with fuel avalible were you set up the
operations. 

Again, having a mirror reflect back the beam from sol sems unlikely. Not
only would the sol beam be spread out over huge distences and diffuse. If
it wasn't soread out a random orbit in the Kuniper belt would quickly drift
out of the beam path, and if it stayed in the beam it would be about
impossibly to reflect the beam that precisely. 

>The Asimov leaves the Kupier outpost to continue its exploration of the
star system. Whatever number of crew is needed to oversee construction
stays behind. As the maser reflector nears completion. The array must be
somehow weighted down to keep it from flying off. Keeping it tethered to
something like the weight of Phoboes would be nice but then Sol would
have to track it to keep the beam on target. It will probably be better to
simply give it enough weight to prevent it from blowing away too fast
while reaccelerating the Asimov. I only hope that the required weight
won't be beyond out ability to put to space. Also, this entire array will
have to be able to maintain its position inside the maser beam which
means some powerful rockets or some angling of the array as mentioned in
Phase 3. 

>PHASE 5: REACCELERATION OF THE ASIMOV/RETURN TO SOL 
>This final phase is pretty self-explanitory. The Asimov's sail (having
been patched up from the flight to TC we hope) is redeployed is manuvered
into the path of the redirected maser beam. Again, it is hoped that a high
terminal velocity will be possible. As the Asimov nears Sol, the array is
turned around and the masers focus straight on to the tatered sail. Mission
ends as the Asimov pulls into the local Starbase. 

The array is the mirrors on the pathfinders. The whole time the beam is
pointing straight at T.C. at the reflectors. The ship is riding that beam
straight back from Tau. I.E. the Tau reflection is shining on its back and
the stronger direct source from sol on its frount. This makes accelerating
out of Tau, much less getting to high speed, very difficult. 

Kelly

===============================================

Date: Mon, 4 Mar 1996 15:31:29 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: Brian Mansur <[email-masked]>, kgstar <[email-masked]>,
David <[email-masked]>, hous0042 <[email-masked]>,
KellySt <[email-masked]>, lparker <[email-masked]>, rddesign
<[email-masked]>, Steve VanDevender <[email-masked]>,
"T.L.G.vanderLinden" <[email-masked]>
Bcc: 
X-Attachments: 
At 1:03 PM 3/4/96, Brian Mansur wrote:
>>From Brian,

>>>At 4:57 PM 3/1/96, Brian Mansur wrote: From Brian
>>>March 1, 1996

>>>MARS HYBRID DESIGN II (Kevin already submitted the first this morning) 

>>>Total mission time: 50+ years
>>>Pathfinder(s) mission flight time: 40+ years Asimov flight time: 24+
years
>>>Asimov exploration phase time: Undetermined 

>Kelly Says:
>>If its going to take 50 year to get there. I think people would put it off
until they could think up a faster ship. 

>I'll tell you right now that it will take you at least fifty years to think up
and build the support systems for another faster ship. Live with 50 years
or else we don't go at all!

Oh really? It took less than 50 years to go from the Wright Brothers flier
to supersonic flight; or from the first mass market cars to the exodus
from the cities to the constructed subburbias. Come to think of it we are
now celibrating the 50 year of the computer. 

50 years is a long time in technology. Also remember that fifty years
would put this mission into the 22nd century! By then phisisists will have
discovered a lot more tricks then Anti-matter. They might have thought of
warp drives for all we know. (Well actually they already thought of them,
but have no practical idea how to do them.) 

>>Or just lose interest in the
>>project.

>Okay, listen up people of America. Unless we can create anti-matter in
copius quantities or build a lot more than 1E7 masers plus solar energy
collectors to power them all so that we can overcome doplar shift on the
reflector, you're going to have to be patient. Half a century really isn't
that long for this kind of a mission.

Thats a very long time to wait around for first initial survey reports! At
61 years (2111) you'ld get you first report back from Tau. If you were that
patient, you wern't that interested. You might as well have just done photo
recon from orbiting 1000 kilometer telescope arrays. You'ld get a lot of
the data, 60 years earlier. 

If your 60 years patent, you probably arn't interested enough to pay the big
bill for this stuff. 

>And remember that twenty-five of the fifty+ years will be an unmanned
part of the mission where the slow moving deceleration mirror gets into
position so that we can send a fast moving ship with the exploration crew.
They will take 12+ years to get to TC and 12+ years to get back and I
figure that they will be there for at least 10. Now if that isn't good enough
for you, I don't know what is. Just how fast do want to go? Warp speed? ;( 

>>ASSUMPTIONS:
>>It is assumed for this mission plan that a high degree of robotic
automation has already made possible the production of at least 1E18 W
needed to power 1E7 masers without much human supervision. It is also
assumed that this maser array is totally dedicated to the mission and that
the beam will be left throughout the mission. 

>>PHASE 1: LAUNCH OF PATHFINDERS
>>At least one heavy pathfider vessel will be sent before the Asimov using
maser sail to reach a terminal velocity of 1/3c. Pathfinder carries several
thousand, heavy duty, heavy weight, individually targetable, disassembled
mirror arrays that will be deployed roughly 30 years later 
>near
>>TC (see reflectors in an upcoming posting). These arrays (probably
making an effective 1000 km+ wide reflector) will reflect maser energy
back to the Asimov for the deceleration phase. The Pathfinder may or may
not have a crew depending on the level of automation available at the time
of launch. 
>>Also, it may or may not carry emergency supplies for the Asimov should 
>they
>>choose to match speed and dock during the deceleration phase. 

>Kelly Says:
>>Are you assuming the beam would be tight enought to be reflected after
11 light years.

>I'm assuming that we can send a mirror the width of Jupiter if we wanted
to. 
>And when I get time to write up the specifics on this idea, you'll see that
the mirror can actually be thousands of individually targeted mirrors
guided by the same kinds of gyros that Kevin uses to aim the masers. 

Kev was aiming the beam electronicly, not mechanically. Also given
orbital mechanics your Jupiter sized mirror array would move out of the
beam. I don't know about out in the jovians, but things here at 1AU move
about a light minutte a week in their orbits. 

>>Not to mention assuming a mirror could hit the ships sail with the
reflected beam, a few light years away? 

>Remeber the gyros.

>>PHASE 2: LAUNCH OF THE ASIMOV
>>The Asimov is maser pushed to a high %c terminal velocity. It is hoped
that the maser propulsion system will be efficient enough to push the
Asimov to a speed at which the effects of time dialation will be useful to
the crew. At the very least, a max speed of .75c is assumed here. 
>>This ship will consist of an ion drive for in system shuttling around TC.
It will also carry the exploration team and their supplies for the mission.
Among the supplies already mentioned in other discusions are seed robots.
They will be used to start a robot workforce that will help construct,
among other things, a precision mirror array to reflect the 
>maser
>>energy from Sol back to the Asimov's maser sail when the exploration
phase is completed.

>>PHASE 3: DECELERATION OF THE ASIMOV
>>The exact process has many variations. If there are several Pathfinders,
each, the one closest to the Asimov will deploy its reflector array and
then move to a safe range from the beam path. The array will enter the
beam path and redirect the maser energy back to the Asimov. The Asimov,
of course, will have turned its sail around (a slow and delicate process). It
will also have moved slightly to the side the maser beam coming from Sol
to prevent blocking of the array. 

>Kelly says:
>>I assume 'array' refers to the reflectors on the pathfinders. 

>I just realized that you can launch the reflective mirror without sticking
it on a pathfinder. The pathfinder was supposed to just be a conviently
protected package for the mirror. But if some shielding ideas that I've
been kicking around are at all worth our time, we can forego the idea of
the pathfinder completely.

>Kelly Says:
>>If the Pathfinders are reflecting the beam off to one side. They will be
pushed out of the beam in the other direction, and accelerated forward.
Given that the beam presure is strong enough push the ships in the first
place, it would be too strong for the ships thrust against. 

>I'm not sure I understand the last sentence. 

The beam holds the projected momentum needed to push our obserdly
heavy ship. If said ship isn't in the beam, the reflectors in the beam will
have to angle relative to the beam. That will mean that the thrust angles
on the reflectors and the receaving ship, will also be angled. Since the
thrust isn't paralell to the beam/course. The ship and reflectors will be
pushed out to the sides. I.E. off the beam, and off course. 

------------\
/
/
\--------

>Brian Says:
>>Some method of periodic or even continuous course correction on both
the Asimov's part and the array's will be required to correct for the angle
at which the maser beam must be reflected. The Asimov may simply angle
its sail slightly with the edge furtherest from the Sol to array beam
tilted back toward Sol. The array will have to use built in rockets, or else
tilt from time to time in the proper direction to allow vectorial force to
push it back into the center of the beam.

>Kelly Says:
>>This might be complicated given the main sail would be curved like a
parachute, not flat.

>Good point. Of course the angle of vectorial force will be tiny considering
the reflector and the Asimov are several AU apart. 

Oh, I forgot you couldn't do that with the reflectors and get the beam to
the ship. Also targeting on a moving ship when you get a few light months
apart is dangerous. 

>Brian Says:
>>Now, assuming that the doplar effect will cause problems with
reflection of the maser beam, another Pathfinder could deploy it's array 
>and
>>continue the decelation process. Note that I don't know if the most
efficient thing that the Asimov can do with the redirected maser beam
will be to simply bounce it back to space or to power a ion drive. The
exhaust from an ion drive would make for nice shielding against large
particles. 
>>One final note. As the Asimov and Pathfinder speeds reach equilibrium
they have the option of docking (assuming the deceleration of the Asimov
brought it close to the Pathfinder when speed equilibrium was reached. At
this point, any crew on the Pathfinder could cross over. Note that the
Asimov could dock with only one Pathfinder. 

>Kelly Writes:
>>It could dock with more than one. But that would depend on their speeds
and relative positions.

>Have to think about that more, I guess. Gotta go to class. I'll finish
replies after 5 CT. 

Kelly

=========================================================

Date: Mon, 4 Mar 1996 16:24:01 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: Brian Mansur <[email-masked]>, kgstar <[email-masked]>,
David <[email-masked]>, hous0042 <[email-masked]>,
KellySt <[email-masked]>, lparker <[email-masked]>, rddesign
<[email-masked]>, Steve VanDevender <[email-masked]>,
"T.L.G.vanderLinden" <[email-masked]>
Bcc: 
X-Attachments: 
At 3:00 PM 3/4/96, Brian Mansur wrote:
>>From Brian,

>Brian Says:
>>PHASE 4: SYSTEM EXPLORATION/CONSTRUCTION OF MASER REFLECTOR 
>>The Asimov enters the Tau Ceti star system's Kupier Belt. At this point
it disassembles its sail and starts scouting for a low gravity, metal rich
Kupier body that is not too far from the maser beam path. Once such a body
is located, the seed robots are deployed to begin a robot community. 
>>Since the Kupier body will be too far away from Tau Ceti for solar
energy collection, it is assumed that the robots will be powered by fusion
reactor that must be brought along (in addition to the fuel). Depending on
the automation technology at the time of launch, these robots will at
least be responsible for construction of a mirror platform needed for
reacceleration to Sol.

>Kelly Says:
>>Why so far out? That doesn't sound like and area we'ld want to do most
of our exploring at. So why make the base there? You could fuel the fusion
reactors with fuel avalible were you set up the operations.

>The reason for putting the base so far out is because whatever Kupier
body we find near the maser beam is going to be orbiting TC very slowly.
It will give us time to set up our reflector and get it into position with
the least amount of effort. It just occured to me that if you find an object
further inside the system whose orbit would be just right at certain times
to let you do the same thing. Of course that also depends upon the orbital
plane of TC.

Object that far out areactually moving faster than orbits closer in. They
just have farther to go. You also have to remember that if the beam is
powerfull enough to push the ship at 10m/s, it will push the lighter
mirror faster. 

Good point about the orbital plane. Ods are Sol won't be in it. 

>Let me see if I can make this more clear. Once the mirror is built, it will
have to be put into the maser beam and it will have to be able to stay
there. So any orbital momentum it has must be overcome by either rockets
or the acceleration force of the maser. Let's face it. We won't have enough
time to weight the mirror down enough to keep it from accelerating. But
by putting the reflector in deep space, it should also be relatively free of
gravitation distraction from TC and other objects, at least until it gets
fast enough that it won't matter. So in some ways the acceleration is
good. 

>About getting fusion fuel from the rock we're already mining. We might
be able to if we can build a surplus of robot workers. As I pointed out in
the summary intro, this whole mission depends on a revolutionary degree
of automation.

>Kelly Says:
>>Again, having a mirror reflect back the beam from sol sems unlikely. Not
only would the sol beam be spread out over huge distences and diffuse. If
it wasn't soraed out a random orbit in the Kuniper belt would quickly drift
out of the beam path, and if it stayed in the beam it would be about
impossibly to reflect the beam that precisely. 

>See above for how we plan to tackle this problem. Also, the mirror
components might be equiped with rockets. Not only do they adjust
position, but they add weight as well. On the downside, they are also yet
another item that must be built in system.

>I'm beginning to see that if we can do all the things I'm saying we're
going to have to, we might just go ahead and make another maser array
complete with solar energy collectors. The whole reason for bothering
with a reflective mirror is to give the Asimov something that is supposed
to be simpler to assemble at TC than a maser array. So unless our
automation is almost 100% automated, we're not going to get much
exploring done. 
>Unfortunately, I'd don't see a better alternative on the table than to
develope this automation.

>That reminds me of a quote: "So you say you want a revolution. Well you
know. We don't want to change the world but . . . well, all right." 

>>The Asimov leaves the Kupier outpost to continue its exploration of 
>the
>>star system. Whatever number of crew is needed to oversee construction
stays behind. As the maser reflector nears completion. The array must be
somehow weighted down to keep it from flying off. Keeping it tethered to
something like the weight of Phoboes would be nice but then Sol would
have to track it to keep the beam on target. It will probably be better to
simply give it enough weight to prevent it from blowing away too fast
while reaccelerating the Asimov. I only hope that the required weight
won't be beyond out ability to put to space. Also, this entire array will
have to 
>be
>>able to maintain its position inside the maser beam which means some
powerful rockets or some angling of the array as mentioned in Phase 3. 

>>PHASE 5: REACCELERATION OF THE ASIMOV/RETURN TO SOL 
>>This final phase is pretty self-explanitory. The Asimov's sail 
>(having
>>been patched up from the flight to TC we hope) is redeployed is
manuvered into the path of the redirected maser beam. Again, it is hoped
that a high terminal velocity will be possible. As the Asimov nears Sol,
the array is turned around and the masers focus straight on to the tatered
sail. 
>Mission
>>ends as the Asimov pulls into the local Starbase. 

>Kelly says:
>>The array is the mirrors on the pathfinders. 

>No, the pathfinders are history (somewhere in deep, deep space by now)
and the deceleration arrays are with them.

>Kelly says:
>>The whole time the beam is
>>pointing straight at T.C. at the reflectors. The ship is riding that beam
straight back from Tau. I.E. the Tau reflection is shining on its back and
the stronger direct source from sol on its frount. This makes accelerating
out of Tau, much less getting to high speed, very difficult. 

>I left out the detail of saying that the Asimov will again be riding the
redirected be just to the side of the incoming beam from Sol, thus
avoiding the drag your worried about. And, of course, we'll have to make
course corrections on the Asimov and the reflector. 

>I'll go ahead and put a few ideas I had for mirror and ship course
corrections here. We could have the Asimov detach its ion drive and cable
connect it to an edge of the wire mesh sail and the hab section. The drive
could then gently pull the whole set up back onto the beam path. We could
also, perhaps have the maser array at Sol periodically decrease power to
allow this tug to do its job without being microwave fried. We would have
to do something about shielding the tug, of course. 

>Perhaps the tug could be a pair light rockets hanging onto opposite sides
of 
>1000km+ wide sail. They could have their own shielding and would be in
excellent positions to do their jobs.

You have to remember these tugs would have to pump out thousands, to
hundreds of thousands of tons of thrust. That's too much to just hang off
the sail. 

Kelly

=============================================================

Date: Tue, 5 Mar 1996 08:36:33 -0500
To: [email-masked] (David Levine)
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: Kelly Starks x7066 MS 10-39 <[email-masked]>, Brian Mansur
<[email-masked]>, hous0042 <[email-masked]>, KellySt
<[email-masked]>, lparker <[email-masked]>, rddesign
<[email-masked]>, Steve VanDevender <[email-masked]>,
"T.L.G.vanderLinden" <[email-masked]>
Bcc: 
X-Attachments: 
At 4:35 PM 3/4/96, David Levine wrote:
>Kelly Starks x7066 MS 10-39 wrote:
>>Thats a very long time to wait around for first initial survey reports! At
61 years (2111) you'ld get you first report back from Tau. If you were that
patient, you wern't that interested. You might as well have just done photo
recon from orbiting 1000 kilometer telescope arrays. You'ld get a lot of
the data, 60 years earlier.

>>If your 60 years patent, you probably arn't interested enough to pay the
big bill for this stuff.

>I agree. If you launch a mission that will not return scientific results in
your lifetime (assume you are in your 30s or 40s when you send the
mission off), most people would probably just say "why not let them do it
-then-, instead?" 

>The payoff is too distant for most corporations, and the bill too big for
governments to justify to the people when considering the length of time
involved. 

>If we can't do it faster, we're not going to do it. 

I'm tending toward the steping stone idea. Try a few of the near by stars
now, and strech when you can. 

>Too bad we don't have a target system with already-contacted ETs.
Deceleration seems to be our biggest problem. They could construct an in-
system maser decelerator... Of course, assuming they trusted us. I don't
know what we'd do if an alien civilization contacted us and asked us to
build a maser array to decelerate their spacecraft.

>Interestingly, many people say that interstellar travel is so amazingly
difficult (and we are seeing part of it) that it won't be accomplished for
millenia, if at all. One of the responses to the Fermi Paradox. But lately I
think we'd agree that interstellar travel is, in fact, possible, but at
horrendous cost. If we had a pre-existing deceleration system (i.e.
cooperative aliens in the target system), however, interstellar travel may
actually not be too difficult. It makes me think of an area of the galaxy
where civilizations may arise frequently, and there is some sort of trade
route set up with masers. You could travel easily between stars if there
were lots of aliens around... But, if (like us) you seem to be alone, you
might be stuck at home. Interesting paradox - if there are places to
colonize, you can't go there. If everywhere is filled up already, you can go
there. 

>Just rambling.

>David

Yeah.

Interesting point about Star travel. The whole idea of the radio search of
the galaxy is that phyisical star travel is impossible. So civilizations
would have to content themselves with randomly transmiting (possibly for
hundreds of thousands of years!), until someone in the galaxy decides to
listen and reply. We have shown that it is possible; not practical yet, but
possible. Given that what civilization would wait hundreds of thousands of
years for an answer, when they could just go look for themselves. 

So in a way, we haven't come up with a doable concept yet, but we've done
better than Carl Sagen and friends. 

Kelly

=======================================================

Date: Tue, 5 Mar 1996 09:15:22 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: kgstar <[email-masked]>, David <[email-masked]>,
hous0042 <[email-masked]>, KellySt <[email-masked]>,
lparker <[email-masked]>, rddesign <[email-masked]>,
Steve VanDevender <[email-masked]>, "T.L.G.vanderLinden"
<[email-masked]>
Bcc: 
X-Attachments: 
At 3:39 PM 3/4/96, Brian Mansur wrote:
>>From Brian 3:34 PM CT 3/4/96

>At 1:03 PM 3/4/96, Brian Mansur wrote:
>>>From Brian,

>>>>At 4:57 PM 3/1/96, Brian Mansur wrote: From Brian
>>>>March 1, 1996

>>>>MARS HYBRID DESIGN II (Kevin already submitted the first this
morning) 

>>>>Total mission time: 50+ years
>>>>Pathfinder(s) mission flight time: 40+ years Asimov flight time: 24+
years
>>>>Asimov exploration phase time: Undetermined 

>>Kelly Says:
>>>If its going to take 50 year to get there. I think people would put it 
>off
>>>until they could think up a faster ship. 

>>Brian Says:
>>I'll tell you right now that it will take you at least fifty years to think
up and build the support systems for another faster ship. Live with 50
years or else we don't go at all!

>Kelly Says:
>>Oh really? It took less than 50 years to go from the Wright Brothers
flier to supersonic flight; or from the first mass market cars to the
exodus from the cities to the constructed subburbias. Come to think of it
we are now celibrating the 50 year of the computer. 

>>50 years is a long time in technology. Also remember that fifty years
would put this mission into the 22nd century! By then phisisists will have
discovered a lot more tricks then Anti-matter. They might have thought of
warp drives for all we know. (Well actually they already thought of them,
but have no practical idea how to do them.) 

>Okay, to avoid a hashed argument (and I apologize for coming down so
hard on my time comment), I concede to your point of possibly being able
to build something faster. It sounds like your idea is improbable but then
I'm proposing that we'll be able to create near 100% autonomous robot
workforces. I'm only saying that, right now, this hybrid idea is the best I
can think of. Of course, as your argument hints, who knows but we might
be able ourselves to find something better given a few more weeks or
months. 

>Brian Says:
>>>Or just lose interest in the
>>>project.

>>Okay, listen up people of America. Unless we can create anti-matter in
copius quantities or build a lot more than 1E7 masers plus solar energy
collectors to power them all so that we can overcome doplar shift on the
reflector, you're going to have to be patient. Half a century really isn't
that long for this kind of a mission.

>Kelly Says:
>>Thats a very long time to wait around for first initial survey reports! At
61 years (2111) you'ld get you first report back from Tau. If you were that
patient, you wern't that interested. You might as well have just done photo
recon from orbiting 1000 kilometer telescope arrays. You'ld get a lot of
the data, 60 years earlier.

>I see where our differences in opinion are coming from. You and I have
different ideas as to what a kind of human universe this hybrid idea will
be taking form. And I admit that it is my fault here because you are
sticking to the LIT charter and I'm not qualifying my designs by noting
that I am not limiting my technology to what would be available to 2050.
Sorry. 

Thats ok. Its an old argument in the group. As I mentioned in those draft
web pages I sent around (and got no responce to!). If you slip the time
table to a cetury from now, you have to start guessing what new
technologies, and Physcics! will be avalible. A hundred years ago Fusion,
fission, relativity, momentum transfer of momentum, and a bunch more
were not enve theories. Physisists (sp?) are currently mutering about
inertian and kinetic energy (i.e. what the hell are they), mater conversion,
controled distortion of space and time, alternate dimentions, faster than
light travel, and even freakier stuff. By 2050 a lot of these mutterings
will be hardened theories, and our designs will look like a Saturn-V the
size of a mountain fueled by burning coal. 

But, if you don't know what we'll get, you got to plan conservativly. 

>As for using 1000 km telescope arrays to scan TC. Given the level of
technology and space infrastructure that I think any of our close to
workable designs are needing, we would have done that already. 

>Question. Isn't there a wavelength resolution limiting how much detail
you can gather on distant objects. What I'm wondering is whether or not
telescopes have the same limitations that light microscopes have when
trying to view objects with detail smaller than the wavelength (in nm) of
the object they are observing.

The wave length limit would be the same. We couldn't resolve objects
smaller than a wavelength of light. Not that thats a big issue in studing
interstellar planets. ;) 

>Kelly Says:
>>If your 60 years patent, you probably arn't interested enough to pay the
big bill for this stuff.

>With the amount of automation I'm assuming here, its the robots who will
be paying the bill. And they don't care (we hope given depending if AI's are
needed for my ideas).

>>And remember that twenty-five of the fifty+ years will be an unmanned
part of the mission where the slow moving deceleration mirror gets into
position so that we can send a fast moving ship with the exploration crew.
They 
>will
>>take 12+ years to get to TC and 12+ years to get back and I figure that 
>they
>>will be there for at least 10. Now if that isn't good enough for you, I
don't know what is. Just how fast do want to go? Warp speed? ;( 

>>>ASSUMPTIONS:
>>>It is assumed for this mission plan that a high degree of robotic
automation has already made possible the production of at least 1E18 W
needed to power 1E7 masers without much human supervision. It is also
assumed that this maser array is totally dedicated to the mission and that
the beam will be left throughout the mission. 

>>>PHASE 1: LAUNCH OF PATHFINDERS
>>>At least one heavy pathfider vessel will be sent before the Asimov
using maser sail to reach a terminal velocity of 1/3c. Pathfinder 
>carries
>>>several thousand, heavy duty, heavy weight, individually targetable,
disassembled mirror arrays that will be deployed roughly 30 years later 
>>near
>>>TC (see reflectors in an upcoming posting). These arrays (probably
making an effective 1000 km+ wide reflector) will reflect maser energy
back to 
>the
>>>Asimov for the deceleration phase. The Pathfinder may or may not have
a crew depending on the level of automation available at the time of
launch. 
>>>Also, it may or may not carry emergency supplies for the Asimov should 
>>they
>>>choose to match speed and dock during the deceleration phase. 

>>Kelly Says:
>>>Are you assuming the beam would be tight enought to be reflected after
11 light years.

>>Brian Says:
>>I'm assuming that we can send a mirror the width of Jupiter if we
wanted 
>to.
>>And when I get time to write up the specifics on this idea, you'll see 
>that
>>the mirror can actually be thousands of individually targeted mirrors 
>guided
>>by the same kinds of gyros that Kevin uses to aim the masers. 

>>Kelly Says
>>Kev was aiming the beam electronicly, not mechanically. Also given
orbital mechanics your Jupiter sized mirror array would move out of the
beam. I don't know about out in the jovians, but things here at 1AU move
about a light minutte a week in their orbits.

>Brian Says:
>If the reflector is construction at Kupier Belt distance, it won't be
moving any faster than Pluto. That is until we put the mirror into the
beam path. 
>Then it will slowly accelerate. With relatively minor course corrections,
it will stay in the beam.

Pluto moves MUCH faster than Earth. Your mirror would quickly move out
of the beam. even if the beam was larger than Earths orbit. 

>>>Kelly Says:
>>>Not to mention assuming a mirror could hit the ships sail with the
reflected beam, a few light years away? 

>>Brian Says:
>>Remeber the gyros.

>>>PHASE 2: LAUNCH OF THE ASIMOV
>>>The Asimov is maser pushed to a high %c terminal velocity. It is hoped
that the maser propulsion system will be efficient enough to push 
>the
>>>Asimov to a speed at which the effects of time dialation will be useful
to the crew. At the very least, a max speed of .75c is assumed here. 
>>>This ship will consist of an ion drive for in system shuttling around TC.
It will also carry the exploration team and their supplies for the mission.
Among the supplies already mentioned in other discusions are 
>seed
>>>robots. They will be used to start a robot workforce that will help
construct, among other things, a precision mirror array to reflect the 
>>maser
>>>energy from Sol back to the Asimov's maser sail when the exploration
phase is completed.

>>>PHASE 3: DECELERATION OF THE ASIMOV
>>>The exact process has many variations. If there are several
Pathfinders, each, the one closest to the Asimov will deploy its reflector
array and then move to a safe range from the beam path. The array will
enter the beam path and redirect the maser energy back to the Asimov. The
Asimov, of course, will have turned its sail around (a slow and delicate
process). It will also have moved slightly to the side the maser beam
coming from Sol to prevent blocking of the array. 

>>Kelly says:
>>>I assume 'array' refers to the reflectors on the pathfinders. 

>>Brian Says:
>>I just realized that you can launch the reflective mirror without
sticking it on a pathfinder. The pathfinder was supposed to just be a
conviently protected package for the mirror. But if some shielding ideas
that I've been kicking around are at all worth our time, we can forego the
idea of 
>the
>>pathfinder completely.

Then how do you slow down the packaged mirrors without the pathfinder
rockets? Or is this the expendable set? I'm confused. 

>>Kelly Says:
>>>If the Pathfinders are reflecting the beam off to one side. They will be
pushed out of the beam in the other direction, and accelerated forward.
Given that the beam presure is strong enough push the ships in the first
place, it would be too strong for the ships thrust against. 

>>Brian Says:
>>I'm not sure I understand the last sentence. 

>>Kelly Says:
>>The beam holds the projected momentum needed to push our obserdly
heavy ship. If said ship isn't in the beam, the reflectors in the beam will
have to angle relative to the beam. That will mean that the thrust angles
on the reflectors and the receaving ship, will also be angled. Since the
thrust isn't paralell to the beam/course. The ship and reflectors will be
pushed out to the sides. I.E. off the beam, and off course. 

>------------\
>/
>/
>\--------

>Brian Says:
>Understood as inevitable. Here are some ideas I put into an e-mail sent to
you just a little earlier today which address the problem. Begin Excerpt
>I'll go ahead and put a few ideas I had for mirror and ship course
corrections here. We could have the Asimov detach its ion drive and cable
connect it to an edge of the wire mesh sail and the hab section. The drive
could then gently pull the whole set up back onto the beam path. We could
also, perhaps have the maser array at Sol periodically decrease power to
allow this tug to do its job without being microwave fried. We would have
to do something about shielding the tug, of course. 

>Perhaps the tug could be a pair light rockets hanging onto opposite sides
of 
>1000km+ wide sail. They could have their own shielding and would be in
excellent positions to do their jobs.
>End Excerpt

Hanging them on the sails doesn't matter. The weight after all is in the
ship, not the sail. 

Given the power levels of the beam, the lateral thrusters on the ship and
mirror assembly would need to be incredable. Possibly prohibativly so. 

>>Brian Says:
>>>Some method of periodic or even continuous course correction on both
the Asimov's part and the array's will be required to correct for the 
>angle
>>>at which the maser beam must be reflected. The Asimov may simply
angle 
>its
>>>sail slightly with the edge furtherest from the Sol to array beam tilted
back toward Sol. The array will have to use built in rockets, or else 
>tilt
>>>from time to time in the proper direction to allow vectorial force to
push it back into the center of the beam.

>>Kelly Says:
>>>This might be complicated given the main sail would be curved like a
parachute, not flat.

>>Brian Says:
>>Good point. Of course the angle of vectorial force will be tiny 
>considering
>>the reflector and the Asimov are several AU apart. 

>>Kelly Says:
>>Oh, I forgot you couldn't do that with the reflectors and get the beam to
the ship.

>Brian Says:
>Huh? I don't understand this.

If you angle the mirrors to counter thrust you back into the beam, you'ld be
reflecting the beam away from the ship not toward it. Trying to anticipate
where the ship is relative to the mirror array would be a problem too. The
mirrors obviously can't 'aim' in the conventional sence due to the time
delay. 

You might try a secondary set of sails rigged to provide lateral thrust.
After all. Only a tiny fraction of the beam will hit the reflectors (The
beam would after all be pretty spread out), and only a fraction of the
reflected beam would hit the main sail (since you can't aim accuratly,
shotgun the area). 

>>Kelly Says:
>>Also targeting on a moving ship when you get a few light months apart
is dangerous.

>Brian Says:
>See my above question on just how well Kev's gyroes could be adapted to
work for mechanical reflection. If this isn't solvable for aiming mirrrors,
I guess its back to the drawing board.

=============================================================

Date: Tue, 5 Mar 1996 09:21:21 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: kgstar <[email-masked]>, David <[email-masked]>,
hous0042 <[email-masked]>, KellySt <[email-masked]>,
lparker <[email-masked]>, rddesign <[email-masked]>,
Steve VanDevender <[email-masked]>, "T.L.G.vanderLinden"
<[email-masked]>
Bcc: 
X-Attachments: 
At 3:48 PM 3/4/96, Brian Mansur wrote:
>>From Brian At 3:45 CT 3/4/96

>>At 3:00 PM 3/4/96, Brian Mansur wrote: 
>>>From Brian,

>>Brian Says:
>>>PHASE 4: SYSTEM EXPLORATION/CONSTRUCTION OF MASER REFLECTOR 
>>>The Asimov enters the Tau Ceti star system's Kupier Belt. At this point
it disassembles its sail and starts scouting for a low gravity, 
>metal
>>>rich Kupier body that is not too far from the maser beam path. Once
such 
>a
>>>body is located, the seed robots are deployed to begin a robot
community. 
>>>Since the Kupier body will be too far away from Tau Ceti for solar
energy collection, it is assumed that the robots will be powered by fusion 
>reactor
>>>that must be brought along (in addition to the fuel). Depending on the
automation technology at the time of launch, these robots will at least be
responsible for construction of a mirror platform needed for 
>reacceleration
>>>to Sol.

>>Kelly Says:
>>>Why so far out? That doesn't sound like and area we'ld want to do most
of our exploring at. So why make the base there? You could fuel the fusion
reactors with fuel avalible were you set up the operations.

>>Brian Says:
>>The reason for putting the base so far out is because whatever Kupier
body we find near the maser beam is going to be orbiting TC very slowly.
It 
>will
>>give us time to set up our reflector and get it into position with the 
>least
>>amount of effort. It just occured to me that if you find an object further
inside the system whose orbit would be just right at certain times to let
you do the same thing. Of course that also depends upon the orbital plane
of TC.

>>Kelly Says:
>>Object that far out areactually moving faster than orbits closer in. They
just have farther to go. You also have to remember that if the beam is
powerfull enough to push the ship at 10m/s, it will push the lighter
mirror faster.

>Brian Says: I'm sick of writing says. From now on its just the name of the
person.
>Brian:
>Doh! Oh well. Guess that just means that we'll have to use an extra
100,000 tons of fuel to slow the array down to keep it inside the beam.
You know, when I joined LIT I really never thought that getting to another
star system would be so hard. Back then I thought you could just say
"engage" and the engines would start up and "whosh." You'd be there after
the commercial break. Ugh!

Yeah, reality sucks some times. MOst of LIT thought we'ld have the drive
systems ironed out in a couple of months. That was nearly 2 years ago. 

>[Much discusion deleted]

>Brian:
>>I'll go ahead and put a few ideas I had for mirror and ship course
corrections here. We could have the Asimov detach its ion drive and cable
connect it to an edge of the wire mesh sail and the hab section. The drive
could then gently pull the whole set up back onto the beam path. We could
also, perhaps have the maser array at Sol periodically decrease power to
allow this tug to do its job without being microwave fried. We would have
to do something about shielding the tug, of course. 

>>Perhaps the tug could be a pair light rockets hanging onto opposite sides 
>of
>>1000km+ wide sail. They could have their own shielding and would be in
excellent positions to do their jobs.

>Kelly:
>>You have to remember these tugs would have to pump out thousands, to
hundreds of thousands of tons of thrust. That's too much to just hang off
the sail.

>Okay, new twist. Leave the blasted maser beam on full and use power
from the masers to convert to electricity and let the tug boat ion
accelerator eat cake (the kind made up of one ion variety of course). You
can tell I'm getting frustrated here.

Many sore head ponding on this wall. We certainly didn't come up with this
crazy interstellar microwave beam sail trick because it sounded easy! 

Kelly

=========================================================

Date: Tue, 5 Mar 1996 09:28:33 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: David <[email-masked]>, Kelly Starks x7066 MS 10-39
<[email-masked]>, hous0042 <[email-masked]>,
KellySt <[email-masked]>, lparker <[email-masked]>, rddesign
<[email-masked]>, Steve VanDevender <[email-masked]>,
"T.L.G.vanderLinden" <[email-masked]>
Bcc: 
X-Attachments: 
At 4:12 PM 3/4/96, Brian Mansur wrote:
>----------
>From: David
>To: Kelly Starks x7066 MS 10-39
>Cc: Brian Mansur; hous0042; KellySt; lparker; rddesign; Steve
VanDevender; T.L.G.vanderLinden
>Subject: Re: MARS HYBRID DESIGN II (First Draft) Date: Monday, March 04,
1996 4:35PM

>Brian 4:08 CT 3/4/96

>Kelly Starks x7066 MS 10-39 wrote:
>>Thats a very long time to wait around for first initial survey reports! 
>At
>>61 years (2111) you'ld get you first report back from Tau. 

>Brian:
>Actually, it will take 50 years. That assumes 35 to 40 years from the
time of the deceleration mirror launch to the final deceleration of the
Asimov. 
>Remember that the Asimov will be launching just 15 to 25 years after
the reflector has been sent up before it. After final deceleration and
exploration begins, the first survey reports will be received 12 years
later around the year 2100 (assuming a decel reflector launch date of
2050 which I am not).

Opps, were sorry.

>I would like to point out that I haven't seen an answer to my question
about the doplar shift effect on a fast moving reflector. If the doplar
effect simply decreases efficiency of the beam before it reaches the
Asimov, that can be compensated for by using more power. Of course that
means building more solar panels and masers but then I'm assuming
increadible automation capability where there is virtually no human cost. 

Don't have numbers, but yes the shift will whipe out most of the power. 

>>Kelly:
>>If you were
>>that patient, you wern't that interested. You might as well have just 
>done
>>photo recon from orbiting 1000 kilometer telescope arrays. You'ld get a
lot of the data, 60 years earlier.

>>If your 60 years patent, you probably arn't interested enough to pay the
big bill for this stuff.

>>David:
>>I agree. If you launch a mission that will not return scientific results in
your lifetime (assume you are in your 30s or 40s when you send the
mission off), most people would probably just say "why not let them do it
-then-, instead?" 

>>The payoff is too distant for most corporations, and the bill too big for
governments to justify to the people when considering the length of time
involved. 

>Brian:
>Who was that one European prince that started looking for a route to
India by sailing around Africa? Didn't it take about 50 years for his dream
to come true. And that after he died? Of course most of us aren't that
patient.

They never made it to China. Ironicly the Chineese were coming around the
other side of Africa at the same time. They gave up because the outside
world was full of infearious that wern't worth talking to. (The government
also though sailers were to uppity.) So they never made it to europe. 

None of them of course is used to the tech of ten years from now being
drasticly better than that of now. We KNOW we will be able to do it much
better later. 

>David:
>>If we can't do it faster, we're not going to do it. 

>Brian:
>This lack of patience on the part of human society is starting really to
bug me. Of course I've no right to complain seeing as how I should have
been patient enough to do my Calculus before replying to these e-mails. 

Its not a limitation. Its just not trying to be stupid and wastfull. 

>>David:
>>Too bad we don't have a target system with already-contacted ETs.
Deceleration seems to be our biggest problem. They could construct an in-
system maser decelerator... Of course, assuming they trusted us. I don't
know what we'd do if an alien civilization contacted us and asked us to
build a maser array to decelerate their spacecraft.

>Perhaps let them come but I'd certainly make sure that they'd have to go
through serious customs checks before we let them anywhere near Earth. 
>Can't have illegal aliens running about now can we? 

;)

Kelly

===========================================================

Date: Tue, 5 Mar 1996 11:26:50 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: Mirrors (first draft)
Cc: David <[email-masked]>, hous0042
<[email-masked]>, jim <[email-masked]>, KellySt
<[email-masked]>, kgstar <[email-masked]>, lparker
<[email-masked]>, rddesign <[email-masked]>, Steve
VanDevender <[email-masked]>, "T.L.G.vanderLinden"
<[email-masked]>, zkulpa
<[email-masked]>
Bcc: 
X-Attachments: 
At 5:12 PM 3/4/96, Brian Mansur wrote:
>Brian 5:10 CT 3/4/96

>Okay, here it is. The mirror paper.

>First off. I'd like to thank everyone for the comments on the MARS Hybrid
II (first draft). Although it has been mangled and shot through, I think it
still has a chance of working. This is because I'm already assuming a
miracle in robotics to make it happen. Why not a few more? But to make it
more believable, here are some ideas on the mirrors to perhaps add (or
eliminate) credibility.

>MASER BEAM REDIRECTING MIRROR:
>This component of my hybrid design was originally meant to be
disassembled and launched aboard a protective pathfinder shell. This is
because the mirror will have to be precision crafted to reflect maser
energy back to the Asimov during its deceleration phase. Whether or not
the mirror will be curved overall I am not knowledgable enough to
determine. But to allow flexiblitity for the design, I planned on making the
entire mirror a composite of individually targetable mirrors of say 10km
to a side. 

Thats kind of the problem with these big structures. They won't stay
precice under these loads. They will flex. Probably need to be flexible like
fabric. 

>Since the total reflective area will span a diameter of at least 1000km,
this mirror will also have to be extremely thin. I figure that by the time
we decide to launch this mission, we should have come up with some
superstrong, superlightweight plastics for the support structure and
reflective surface. This is necessary to make this array light enough to
push. A point of confusion for me is just what a microwave reflector
would be like in terms of the reflective surface. I have heard that a
reflective sail could be made like chicken wire with spaces of say 1 mm
between wires. 
>That would certainly lighten the load.

A looser mesh than that, possibly up to 1/2 cm mesh. But varies alot
depeding on transmitted frequency and dopler shift. 

>Refiguring my reflector ideas, I decided that the mirror could be
protected against the interstellar debris using a lightweight solid shield. 
>See Shielding below for an explanation. If this can be accomplished, then
we could use the mirror as its own sail, pushing it via masers. It would be
heavy but that is actually good because it means less acceleration during
the Asimov's decel phase and so less distance between the two to aim
across. 

>Aiming the array would be accompished by applying the same kinds of
gyros that are employed on the masers to keep the beams on target from
the Sol end. I hope this is adaption can be made because my entire
deceleration scheme really depends on it. I note that these gyros will need
some kind of protection from the maser beam and that is something I've
not yet worked out.
>In flight course corrections will be needed for this reflector to work.
This will have to be accomplished with onboard rockets. Just how
powerful they must be and how much fuel they must carry depends on how
light we can get the mirror structure. If the mirror is chicken wire, this
shouldn't be much of a problem.

>SHIELDING:
>Here's my proposal on shielding. Make a bag out of chicken wire and fill it
with superlightweight ping pong balls or with a superlightweight foam.
These substances would act like a dust or gas barrier but would stay
inside the bag. Anything that hits the bag will probably cause a sizable
explosion so replenishment of these materials will be needed. Robots can
scout the surface of the bag to patch and reknit gaping holes. The size of
the bag depends on how much shielding we want. 
>It just occured to me that this idea may not work very well because the
chemical structural of the pp balls or the foam will probably be altered by
the tremendous heat from collisions. Kelly, I believe, had proposed keeping
a plasma in a bag several km in thickness. I don't know how to contain
plasma in such a thin bag as chicken wire even it the wire was producing a
hefty field. Also, how do we keep the plasma a plasma. How about a "less"
energetic charged dust cloud. Would that stay in a magnetic field better? 
>Could we keep it charged. Wouldn't we have static electricity problems? 

My shield wasn't a plasma shield. I just assumed the ship launched a cloud
of electrostatically charged dust ahead of the ship. Given the charge. The
cloud would spread out a bit, but wouldn't clump up on the ship. Dust
plowing back past the ship would need to be scooped up before it got out
past the sides, and relaunched forward. 

On the other hand your huge frontal area mirrors wouldn't need to worry
about that. You might even just ignore the shield and assume a certain % of
the mirror mesh will be eroded during the flight, and carry extra mirrors. 

>So much for bolstering my hybid design. By the way. From now on I'm
going to officially call it an ARGOSY class starship. Since I'll probably
have nothing better to do over spring break (like relaxing?), I'll see if I
can improve my design. Expect to see a lot of ideas borrowed from the
Explorer design. I should at least be able to give the group a decent
description along with a critic of the problems associated with the thing.
Oh, and a long list of assumptions as well.

Great! I was hoping we'ld get a fleet of compeating ship designs! We can
try to cross link our pages when they are uploaded by Dave. 

Let me know if you want copies or help.

Kelly

==========================================================

Date: Tue, 5 Mar 1996 11:41:23 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: David <[email-masked]>, kgstar <[email-masked]>,
Brian Mansur <[email-masked]>, hous0042 <[email-masked]>,
KellySt <[email-masked]>, lparker <[email-masked]>, rddesign
<[email-masked]>, Steve VanDevender <[email-masked]>,
"T.L.G.vanderLinden" <[email-masked]>
Bcc: 
X-Attachments: 
At 10:03 AM 3/5/96, Brian Mansur wrote:
>Brian 9:56 CT 3/5/96

>David:
>>Just rambling.

>>David

>Kelly
>>Yeah.

>>Interesting point about Star travel. The whole idea of the radio search of
the galaxy is that phyisical star travel is impossible. So civilizations
would have to content themselves with randomly transmiting (possibly for
hundreds of thousands of years!), until someone in the galaxy decides to
listen and reply. We have shown that it is possible; not practical yet, but
possible. Given that what civilization would wait hundreds of thousands of
years for an answer, when they could just go look for themselves.

>>So in a way, we haven't come up with a doable concept yet, but we've
done better than Carl Sagen and friends.

>Brian
>So how does it feel to be on the cutting edge ;) of starship design? What's
sad is that we are the only ones who really look at this problem from at
least a semi-real perspective. And whats sadder is that we're finding that
we have to be completely unrealistic (by today's tech standards) to think
up anything that would get us to TC.

Well there have been some serious attempt to do this. They ran into most
of the same problems. But, we've stuck at it longer, and are more widely
visible given the web. So we might keep more discusion going. 

Kelly

================================================================

Date: Tue, 5 Mar 1996 11:43:09 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: David <[email-masked]>, Kelly Starks x7066 MS 10-39
<[email-masked]>, Brian Mansur <[email-masked]>, hous0042
<[email-masked]>, KellySt <[email-masked]>, lparker
<[email-masked]>, rddesign <[email-masked]>, Steve
VanDevender <[email-masked]>, "T.L.G.vanderLinden"
<[email-masked]>
Bcc: 
X-Attachments: 
At 10:21 AM 3/5/96, Brian Mansur wrote:
>Brian 10:15 CT 3/5/96

>>Kelly Starks x7066 MS 10-39 wrote:
>>Pluto moves MUCH faster than Earth. Your mirror would quickly move out
of the beam. even if the beam was larger than Earths orbit. 

>>David
>>Pluto's mean orbital velocity is 4.74 km/sec. Earth's mean orbital
velocity is 29.79 km/sec. 

>Why is the mean orbital velocity of Pluto 4.74 compared to a much larger
29.79. Did you get the numbers mixed up. I'm confused. 

So am I. This does fit with my understanding and exerience with orbital
mechanics. 

Kelly

==========================================================

Date: Tue, 5 Mar 1996 12:50:32 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: MARS HYBRID DESIGN II (First Draft)
Cc: Brian Mansur <[email-masked]>, kgstar <[email-masked]>,
David <[email-masked]>, hous0042 <[email-masked]>,
KellySt <[email-masked]>, lparker <[email-masked]>, rddesign
<[email-masked]>, Steve VanDevender <[email-masked]>,
"T.L.G.vanderLinden" <[email-masked]>
Bcc: 
X-Attachments: 
At 10:48 AM 3/5/96, Brian Mansur wrote:
>>From Brian 10:40 AM CT 3/5/96

>[Much discussion deleted]

>>Kelly Says:
>>>Thats a very long time to wait around for first initial survey reports! 
>At
>>>61 years (2111) you'ld get you first report back from Tau. If you were
that patient, you wern't that interested. You might as well have just 
>done
>>>photo recon from orbiting 1000 kilometer telescope arrays. You'ld get a
lot of the data, 60 years earlier.

>>Brian
>>I see where our differences in opinion are coming from. You and I have
different ideas as to what a kind of human universe this hybrid idea will 
>be
>>taking form. And I admit that it is my fault here because you are
sticking to the LIT charter and I'm not qualifying my designs by noting
that I am 
>not
>>limiting my technology to what would be available to 2050. Sorry. 

>>Kelly
>>Thats ok. Its an old argument in the group. As I mentioned in those draft
web pages I sent around (and got no responce to!). If you slip the time
table to a cetury from now, you have to start guessing what new
technologies, and Physcics! will be avalible. A hundred years ago Fusion,
fission, relativity, momentum transfer of momentum, and a bunch more
were not enve theories. Physisists (sp?) are currently mutering about
inertian and kinetic energy (i.e. what the hell are they), mater conversion,
controled distortion of space and time, alternate dimentions, faster than
light travel, and even freakier stuff. By 2050 a lot of these mutterings
will be hardened theories, and our designs will look like a Saturn-V the
size of a mountain fueled by burning coal. 

>>But, if you don't know what we'll get, you got to plan conservativly. 

>Brian
>I'm hoping that conservative includes future automated industry that
makes today's automated factories look like how the first English
factories do compared to today's.

I'm kind of dubious on that one. You are talking about fully self replicating
machines, constructing power transmitters with billions of times the
power of Earths current electric grid, and and mirrors the size of planets,
all fielded in 50 years. I'ld kind of think that was a non conservative
assumption. 

>[Much more discussion deleted]

>>Brian Says:
>>If the reflector is construction at Kupier Belt distance, it won't be 
>moving
>>any faster than Pluto. That is until we put the mirror into the beam path. 
>>Then it will slowly accelerate. With relatively minor course
corrections, it will stay in the beam.

>>Kelly
>>Pluto moves MUCH faster than Earth. Your mirror would quickly move out
of the beam. even if the beam was larger than Earths orbit. 

>Brian
>(imitating Homer Simpson's voice) Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh!
Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! 
>Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh! Doh!

>David gave me these numbers
>Pluto's mean orbital velocity is 4.74 km/sec. Earth's mean orbital
velocity is 29.79 km/sec. 

>Are these right? They seem backwards.

I'ld agree. It seems odthat you'ld accelerate out from the inner system to a
slower velocity. I suppose you might be losing the dif to potential energy
changes. 

But I suppose it isn't critical for our discusion. Assumeing a beam
diameter 40 times the dimeter of earth. 4.76Km/s will still have you
cross the beam in 31 hours. 

>>Kelly
>>Then how do you slow down the packaged mirrors without the pathfinder
rockets? Or is this the expendable set? I'm confused. 

>Brian:
>The decel mirrors are expendable. Again, considering the automation level
of the civilization necessary just to put together such mirrors and maser
arrays to launch them, I'm not worried about the cost. 

I've noticed the cost isn't discused much by us. Stark raving fear perhaps? 

>>>Kelly Says:
>>>>If the Pathfinders are reflecting the beam off to one side. They will be
pushed out of the beam in the other direction, and accelerated forward.
Given that the beam presure is strong enough push the ships in the first
place, it would be too strong for the ships thrust against. 

>>>Brian Says:
>>>I'm not sure I understand the last sentence. 

>>>Kelly Says:
>>>The beam holds the projected momentum needed to push our obserdly
heavy ship. If said ship isn't in the beam, the reflectors in the beam will 
>have
>>>to angle relative to the beam. That will mean that the thrust angles on
the reflectors and the receaving ship, will also be angled. Since the thrust
isn't paralell to the beam/course. The ship and reflectors will be pushed
out to the sides. I.E. off the beam, and off course. 

>>------------\
>>/
>>/
>>\--------

>>Brian Says:
>>Understood as inevitable. Here are some ideas I put into an e-mail sent
to you just a little earlier today which address the problem. Begin Excerpt
>>I'll go ahead and put a few ideas I had for mirror and ship course
corrections here. We could have the Asimov detach its ion drive and cable
connect it to an edge of the wire mesh sail and the hab section. The drive
could then gently pull the whole set up back onto the beam path. We could
also, perhaps have the maser array at Sol periodically decrease power to
allow this tug to do its job without being microwave fried. We would have
to do something about shielding the tug, of course. 

>>Perhaps the tug could be a pair light rockets hanging onto opposite sides 
>of
>>1000km+ wide sail. They could have their own shielding and would be in
excellent positions to do their jobs.
>>End Excerpt

>Kelly:
>>Hanging them on the sails doesn't matter. The weight after all is in the
ship, not the sail.

>>Given the power levels of the beam, the lateral thrusters on the ship and
mirror assembly would need to be incredable. Possibly prohibativly so. 

>Brian
>Are you saying that the power level of the beam will keep us from
manuvering? If so, we can periodically turn it off like I suggested. 

Well my thought was that the main beam would throw the ship and mirror
off to the side very quickly. Assuming a 1% lateral thrust, thats a .1 m/s
accell. You'ld drift 373,000 kilometers and get a lateral speed of 8.6
kilometers per secound, after 1 day. (Well ok you'ld exit the beam after a
couple hours and stop accelerating.) Rockets that could push back against
that load would rival the stardrive for powe. But of couse you can't thrust
laterally without twisting the mirrors (no known material can stay
optically flat over that distence under any load.) 

So if everything isn't precisely balenced and trimed you'ld get radically
out of alignment. If that happens not only do you lose power and have a
hell of a time geting back aligned. Since the ships could be light months
apart, you couldn't correct your aim for where the ship really is. 

>What we need is a powerful enough rocket, probably ion drives that can
periodically tug the Asimov, its sail, and the tugs themselves, perhaps a
few thousand km back toward the beam every now and then. Lets assume
that the tug accelerator weighs 10 tons/m, and the drive needs to be 1000
m long. 
>This does not account for fuel because I don't know what that will be:
hopefully 10ton/m is an overestimate. Two accelerators will weigh
20,000 together. By the way. At rest, I figured we might put them along an
axis perpendicular to the direction we want to tugs to tug. 

>What we need to do is find exactly how many km we'll have to adust over
the flight. Then we can find better weight values. To find the km
displacement, lets say that for safety, the Asimov is traveling 100,000
km to the side of the beam. Also assume that the decel reflector (during
decel phase) and the reaccel mirror (durring reaccel phase) never come
closer than 1 AU from the Asimov. Can anyone do the trig here? I'll see if I
can find the time get the numbers myself, but I don't make promises even
when relatively simple mathmatics are involved. 

>I also have an idea to add to my mirror paper. I'll probably reprint this
next paragraph in it later but here it is anyway. How about putting a
Fresnel lens in the path to TC to refocus our beam. The lens could be of the
thin variety, although I believe we would have some power losses through
the lens.

>The lens could be launched and stopped at the desired position if we
attached detachable reflective sail blankets on both sides. One side would
reflect maser energy for acceleration. The other would be the surface
facing TC to which a decel mirror. The decel mirror would be like the kind
envisioned for the Asimov and so would probably be launched separately. I
guess this idea would add several more years to our launch time-table
assuming we only had enough masers and power to launch the weight of 1
reflective mirror at a time. By the way, I have little conception as to how
much this Fresnel lens would weigh and I don't know if it would
experience acceleration while refocusing. For aiming I suggest the famous
Waveguide gyros simply because I don't have any better ideas. 

>>>Brian Says:
>>>>Some method of periodic or even continuous course correction on both
the Asimov's part and the array's will be required to correct for the 
>>angle
>>>>at which the maser beam must be reflected. The Asimov may simply
angle 
>>its
>>>>sail slightly with the edge furtherest from the Sol to array beam
tilted back toward Sol. The array will have to use built in rockets, or else 
>>tilt
>>>>from time to time in the proper direction to allow vectorial force to 
>push
>>>>it back into the center of the beam. 

>>>Kelly Says:
>>>>This might be complicated given the main sail would be curved like a
parachute, not flat.

>>>Brian Says:
>>>Good point. Of course the angle of vectorial force will be tiny 
>>considering
>>>the reflector and the Asimov are several AU apart. 

>>>Kelly Says:
>>>Oh, I forgot you couldn't do that with the reflectors and get the beam to
the ship.

>>Brian Says:
>>Huh? I don't understand this.

>>Kelly
>>If you angle the mirrors to counter thrust you back into the beam, you'ld
be reflecting the beam away from the ship not toward it. Trying to
anticipate where the ship is relative to the mirror array would be a
problem too. The mirrors obviously can't 'aim' in the conventional sence
due to the time delay.

>Brian
>Don't we already have computers that could be programed to reasonably
figure this aiming problem out?

They could given current accurate info. But given that the info has to
travel at the spped of light, it would be months out of date by the time the
mirror systems got it. Given that the actuall rates will varry back and
forth a bit durring the interveaning time (given random flexing of the sail,
and random variations of the beam), and we can't predict what these
variations will be. The aiming calculations will be precise calculations
bases on very bad information. I.E. computer generated guesses. Even
assuming not one unexpected thing ever happens on the ship or mirror. If
you guess wrong even once. You're aiming the beam into empty space and
the ship is racing away from where you think it is. 

Just to complicate things. The mirror is moring at a high fraction of the
speed of light. So relatavistic distortion will distort the beam, mirror,
and apparent space. 

>>Kelly
>>You might try a secondary set of sails rigged to provide lateral thrust.
After all. Only a tiny fraction of the beam will hit the reflectors (The
beam would after all be pretty spread out), and only a fraction of the
reflected beam would hit the main sail (since you can't aim accuratly,
shotgun the area).

>Brian
>I'm not sure I follow you here? I think I need a diagram. 

----------\
/ /
//
\--------

A little hard to folow I know, but you have a secound set of sails
connected to each mirror and sail, angled to the beam shining on them.
These are angled to provide lateral thrust against the main lateral thrust
of the main mirror/sails . They would use parts of the beam that pass to
the side of the areas that the mirror and sail would see (yes that means
the beam would need to be huge, which would waste the vast majority of
its power. Probably 99%- 99.99% of it). 

Oh, and you have to make sure the cross thrust dosen't distort the
optically perfect surfaces or the mirrors. 

>>>Kelly Says:
>>>Also targeting on a moving ship when you get a few light months apart
is dangerous.

>>Brian Says:
>>See my above question on just how well Kev's gyroes could be adapted to 
>work
>>for mechanical reflection. If this isn't solvable for aiming mirrrors, I
guess its back to the drawing board.

>Brian
>So does anyone know if these gyros will work. Kev? Haven't heard from
you yet bud.

Even if the gyros would work, how flat can you keep hundreds of miles of
unsupported (you are in spec) chicken wire being blown down wind under
VERY high thrust loads? 

Kelly

============================================================

Date: Tue, 5 Mar 1996 12:55:24 -0500
To: Brian Mansur <[email-masked]>
From: [email-masked] (Kelly Starks x7066 MS 10-39)
Subject: Re: Mirrors (first draft)
Cc: Brian Mansur <[email-masked]>, kgstar <[email-masked]>,
David <[email-masked]>, hous0042 <[email-masked]>,
jim <[email-masked]>, KellySt <[email-masked]>, lparker
<[email-masked]>, rddesign <[email-masked]>, Steve
VanDevender <[email-masked]>, "T.L.G.vanderLinden"
<[email-masked]>, zkulpa
<[email-masked]>
Bcc: 
X-Attachments: 
At 10:57 AM 3/5/96, Brian Mansur wrote:
>Brian 10:50 AM CT 3/5/96,

>Thanks for the comments. I'll try to reply to them in a day or two (I'll be
busy for the rest of this week on School Club activities and homework).
But here's a little something.

>[much discussion deleted]

>>Brian
>>So much for bolstering my hybid design. By the way. From now on I'm
going to officially call it an ARGOSY class starship. Since I'll probably
have nothing better to do over spring break (like relaxing?), I'll see if I
can improve my design. Expect to see a lot of ideas borrowed from the
Explorer design. I should at least be able to give the group a decent
description along with a critic of the problems associated with the thing.
Oh, and a long list of assumptions as well.

>>Kelly
>>Great! I was hoping we'ld get a fleet of compeating ship designs! We can
try to cross link our pages when they are uploaded by Dave. 

>>Let me know if you want copies or help. 

>Brian
>A word of warning is that I still have to work with BMP. I'm afraid that I
wasn't able to download the GIF program you gave me so all I can do for
now is send bit demons. I can do some decent drawings with the bit
however and I will over the break. I was wondering if you could compress
them and send them on to the rest of the group so that their hard drives
don't explode. 

I'm not sure I can handel BMP files. I'm sure I didn't send you a program
given that my stuff is all Macintosh, and it sound like you are an IBMer. 

>Glad to hear that you're enthusiastic about the idea. I'm beginning to see
already that much of the ARGOSY design will be vague, however. It figure
that it will at least have a similar summary as see in my Hybrid first
draft plus troubleshooting points.

>By the way, something I also plan to get to is an e-mail discussing the
decel problems with the EXPLORER. Its a great idea if drag can be
overcome with minimal power losses. Loading the decel/reacel track is
also a pain. 

Stoping these things is a nightmare! We can't carry enough fuel (unless the
ships get EXTREEAME), and we can't beam it, because the beam only pushes
one way. 

Perhaps we're using these beams wrong? hummm. 

Kelly