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MARS HYBRID DESIGN II (First Draft)
>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
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.
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.
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.
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.
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.
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.