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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
>>>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
>>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
>>take 12+ years to get to TC and 12+ years to get back and I figure that
>>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? ;(
>>>     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.
>>>     At least one heavy pathfider vessel will be sent before the Asimov
>>>using  maser sail to reach a terminal velocity of 1/3c.  Pathfinder
>>>several thousand, heavy duty, heavy weight, individually targetable,
>>>disassembled mirror arrays that will be deployed roughly 30 years later
>>>TC (see reflectors in an upcoming posting).  These arrays (probably making
>>>an effective 1000 km+ wide reflector) will reflect maser energy back to
>>>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
>>>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
>> And when I get time to write up the specifics on this idea, you'll see
>>the mirror can actually be thousands of individually targeted mirrors
>>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.
>>>     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
>>>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
>>>robots.  They will be used to start a robot workforce that will help
>>>construct, among other things, a precision mirror array to reflect the
>>>energy from Sol back to the Asimov's maser sail when the exploration phase
>>>is completed.
>>>     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
>>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
>>>at which the maser beam must be reflected.  The Asimov may simply angle
>>>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
>>>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
>>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.


Kelly Starks                       Internet: kgstar@most.fw.hac.com
Sr. Systems Engineer
Magnavox Electronic Systems Company
(Magnavox URL: http://www.fw.hac.com/external.html)