Forrest Bishop
Institute of Atomic-Scale Engineering, Seattle, Washington, USA
http://www.speakeasy.org/~forrestb
Abstract
The rapidly improving ability to build atomically precise structural materials of
extreme strength-
to-mass ratio will permit a revolution in aerospace engineering. Graphenes, or
'Buckytubes' may
become available in commercial quantities, allowing the realization of previously
untenable
proposals, such as the 'Skyhook', or geosynchronous tether, for example. A number of
novel
spacecraft propulsion systems and machines are presented, as well as new applications for
some
very ancient devices. The crossbow and other mechanical catapults are re-examined in
light of this
materials development. A design for an electrically powered, automatic Graphene crossbow
capable
of loosing 10 kg payloads at 5 km/sec is presented.
A Solar System-wide transportation system is proposed by the author for freight and
for
spacecraft propulsion. A network of accelerator/decelerator stations in various positions
around the
Solar System pass 'Smart Pellets' and other forms of matter and energy between each
other, to
planets and other bodies, and to spacecraft in transit. The systems presented here are
amenable to
inclusion in that proposal.
Between the proposals for particle beam and pellet stream spacecraft propulsion lies
an immense,
largely unexplored spaceflight regime. Pushing a spacecraft using a collimated beam of
mesoscopic
particles, very roughly on the order of a nanogram mass each (plus or minus several
orders of
magnitude), presents new opportunities for high speed interplanetary manned
transportation. This
kind of beam can be tailored in velocity, mass flow, and beam profile parameters to fit
the mission
requirements. The ballistic coefficient, or mass-to-cross-section ratio of this type of
particle is much
greater than single atom particle beams, allowing more precise control over pointing and
dispersion. With atom counts per particle reaching into the millions, molecular
nanotechnologies
may permit the inclusion of entire guidance systems. The receiver onboard the spacecraft
may be as
simple as a pusher plate, or may incorporate particle ionization and magnetic mirroring.
Combining the concepts of solar sailing and mesoparticles leads to the notion of
mesoscopic
solar sails. A mesoparticle beam composed of thin film sails with nanoscale electronics
and
actuators may be able to accelerate, turn, and navigate itself to a target spacecraft.
Its accelerator
may be the Sun, or a laser located on a deep space 'relay station'. The magnetic sail
analog, though
suffering a scaling disadvantage, is investigated briefly.
The performance of the rotating tether, or sling, is considerably enhanced by
constructing it of
Graphene fiber. A relatively short sling with a reasonable taper ratio can attain tip
velocities of
several tens of km/sec, along with firing rates of several hertz, making it an attractive
substitute for
the Mass Driver. Scaling down further, the notion of a mesoparticle sling is introduced.
A planar
array composed of many thousands of centimeter-size slings and associated support systems
forms
a type of mesoparticle beam projector.
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Some References
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[ ] Bishop, F., "Open Air Space Habitats", (1997), in "Tools for the Next Millennium",
CRC Press, Lance Chambers, Ed.
[ ] Bishop, F., "The Construction and Utilization of Space Filling Polyhedra for
Active Mesostructures", (1995), available at: http://www.speakeasy.org/~forrestb
[ ] Bishop, F., "A Proposed MNT Active Cell", (1996), available at:
http://www.speakeasy.org/~forrestb
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(1996) available at: http://www.speakeasy.org/~forrestb
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