Some Novel Space Propulsion Systems
Forrest Bishop*
Institute
of Atomic Scale Engineering
This is an abstract
for a poster to be presented at the
Fifth
Foresight Conference on Molecular Nanotechnology.
The full paper is available here.
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 and braked, fully automatic Graphene
crossbow capable of loosing 10 kg payloads at several 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 receiver onboard the spacecraft may be as
simple as a pusher plate, or may incorporate particle ionization
and magnetic mirroring.
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 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.
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'. Several sail structures
are presented. The magnetic sail analog, though suffering a
scaling disadvantage, is also investigated.
*Corresponding Address:
P. O. Box 30121, Seattle, WA 98103, ph: (206)-367-5268, email: [email protected]
(abstract references available)
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