space travel can change the world

The cost and complexity of space travel has been cited as a reason
that space travel hasn't achieved much since the landing of men on the
moon in the late 1960s through early 1970s. I would beg to differ.

It is true not much improvement in rockets has occured in the last 30
years, especially when compared to the first 30 years of rocket
development. This is due entirely to lack of investment in rocket
development. Such investments largely ended when the US and USSR
achieved their missile development goals. The Delta, Atlas and Titan
space launch vehicles were built around missiles developed at the same
time. Much of the development cost was done on the civilian purse
through NASA. Just as much nuclear research was accomplished through
the civilian reactor programs of the AEC. Where are real interest lie
is to note that for every space launch vehicle built around these
rockets over 100 missiles were built around the same rocket design.
By the time America was assured of landing on the moon, continued
investment which would undoubtedly produce additional cost reductions,
was curtailed.

Even so, significant changes were wrought in the world due to early
successes in space travel;

(1) Global communications networks, with it global business and
internet.
(2) Global reconnaissance and weather satellites, with it, Gaia
hypothesis
(3) Pictures of Earth from vicinity of moon, with it, Environmental
movement
(4) Possible global thermonuclear war, with it, an end to all out
global war
(5) Global navigation satellites

In the near term additional global services can be contemplated;

(6) Global wireless hotspot - a vast network of powerful satellites
having a phased array microwave downlink uplinnk maintain stationary
virtual cells on Earth's surface as they pas overhead, and communicate
with quite modest portable ground stations (think two-way Sirus
satellite radio) and with each other via open optical laser beams.
Broad availability of wireless broadband acorss the surface of the
Earth allows people to live anywhere and work anywhere else via
telepresence and telerobotics.

(7) Global powernet - a network of lightweight solar power satellites
beam IR laser energy from solar pumped lasers at 1,000 nm wavelength
to silicon based solar panels on the ground. Operating at 1/2 solar
intensity, these ground receivers produce over 10x the energy in a
year when powered from space powersats than they do when powered by
sunlight alone. The solar pumped laser operates with sunlight
focused by a large inflatable concentrator on orbit.

(8) Asteroid capture/deflection - nuclear pulse propulsion techniques
are capable of moving worldlets - asteroids and asteroid fragments -
using the existing weapons grade materials already inventoried
throughout Earth by nuclear weapons states. This technique may be
used to deflect an errant asteroid from collision with Earth. It may
also be used to bring a rich asteroid into stable orbit around Earth.
This last possibility may be used to inspire global cooperation on the
ultimate peaceful disposal of nuclear materials. Asteroids that are
captured may then be mined and materials processed into useful
products and goods using telerobotics and solar power. These products
may be then exported to Earth using a GPS guided supply capsule, or
stay in orbit to expand the range of products available to be made in
space, or support expanded human presence in space. For example,
large pressure vessels can be made in orbit and used to grow food and
fiber in orbiting farms and forests. The food and fiber may be
processed and exported to Earth, or across the solar system, wherever
demand exists for it.



EXAMPLE - mining Ceres

Suppose Ceres, the largest asteroid in the solar system, is found to
be rich industrial materials. A nuclear pulse spaceship is sent there
with sufficient equipment and personnell to establish a semi-
automated, solar powered production cell, to make a series of space
colonies that are then dispatched to Earth.

http://en.wikipedia.org/wiki/Hohmann_transfer_orbit
http://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29
http://en.wikipedia.org/wiki/Project..._propulsion%29
http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
http://en.wikipedia.org/wiki/Antimat...lse_propulsion
http://en.wikipedia.org/wiki/Antimatter_rocket
http://en.wikipedia.org/wiki/Self-replicating_machine
http://en.wikipedia.org/wiki/Self-replication
http://en.wikipedia.org/wiki/Von_Neu...al_constructor
http://en.wikipedia.org/wiki/List_of...y_applications

An estimate can be made of what might be required to do something
amazing...

Earth: 1.00 year, 1.00 AU
Ceres 4.60 year, 2.77 AU

A 200,000 metric ton 'mid-range' Orion type spacecraft with 40%
payload fraction carries 80,000 metric tons of payload, and a crew of
800 on a journey to the dwarf planet Ceres.

A hohmann transfer orbit takes 1 year 111 days 41 minutes and 40
seconds to complete, and requires 6.294 km/sec add on velocity at
Earth, and 4.836 km/sec add on at Ceres to circularize the orbit.
With an exhaust speed of 20 km/sec this requires a propellant fraction
of 42.7% - 85,350 metric tons. This exhaust jet has a total energy of
17 TJ. Nuclear pulse rocketry is about 50% efficient - so, that's 34
TJ total energy required.

Assuming this energy comes from anti-protons stored aboard the vehicle
to energize propellants like lead also stored board the vehicle, this
requires 380 milligrams of anti-matter.

Once on planet 10,000 metric tons of solar powered self-replicating
hardware is established to process a portion of the 9.46e+20 kg of
material into useful products. With a specific rate of energy use of
100 watts per kg this initial 'seed' requires 1 MW to function fully.
The system is ultimately solar powered and at 2.77 AU requires 20,000
sq m of solar collector area (thin film concentrator) massing 1/500th
of a MT. The 160 m diameter concentrator based power unit masses only
2 kg.

The self replicating system processes the raw material on Ceres, and
manufactures daughter elements that double the replicating mass every
30 days. Only 1 part in 100 is assumed to be used by the self-
replicating systems Thus the following table can be prepared;

Days Mass Collectors Diam (m)
MT

0 10000 1 160.0
30 20000 2 226.3
60 40000 4 320.0
90 80000 8 452.5
120 160000 16 640.0
150 320000 32 905.1
180 640000 64 1,280.0
210 1280000 128 1,810.2
240 2560000 256 2,560.0
270 5120000 512 3,620.4
300 10240000 1024 5,120.0
330 20480000 2048 7,240.8
360 40960000 4096 10,240.0
390 81920000 8192 14,481.5
420 163840000 16384 20,480.0
450 327680000 32768 28,963.1
480 655360000 65536 40,960.0
510 1310720000 131072 57,926.2
540 2621440000 262144 81,920.0
570 5242880000 524288 115,852.4
600 10485760000 1048576 163,840.0
630 20971520000 2097152 231,704.8
660 41943040000 4194304 327,680.0
690 83886080000 8388608 463,409.5
720 1.67772E+11 16777216 655,360.0
750 3.35544E+11 33554432 926,819.0
780 6.71089E+11 67108864 1,310,720.0
810 1.34218E+12 134217728 1,853,638.0
840 2.68435E+12 268435456 2,621,440.0
870 5.36871E+12 536870912 3,707,276.0
900 1.07374E+13 1073741824 5,242,880.0
930 2.14748E+13 2147483648 7,414,552.0
960 4.29497E+13 4294967296 10,485,760.0
990 8.58993E+13 8589934592 14,829,104.0
1020 1.71799E+14 17179869184 20,971,520.0
1050 3.43597E+14 34359738368 29,658,208.0
1080 6.87195E+14 68719476736 41,943,040.0
1110 1.37439E+15 1.37439E+11 59,316,416.0
1140 2.74878E+15 2.74878E+11 83,886,080.0
1170 5.49756E+15 5.49756E+11 118,632,832.0
1200 1.09951E+16 1.09951E+12 167,772,160.0
1230 2.19902E+16 2.19902E+12 237,265,664.1
1260 4.39805E+16 4.39805E+12 335,544,320.0
1290 8.79609E+16 8.79609E+12 474,531,328.1

In less than 4 years Ceres has been totally processed, and one part in
100 is processed into useful products. Total power collected by the
solar panels covering half the diameter of Ceres is equal to half that
of the entire industrial capacity of Earth. 8.8 TW.

It is assumed that adequate fissile materials, and other materials
(such as Lithium 6 and Deuterium) are found to power nuclear pulse
rockets built on planet.

http://en.wikipedia.org/wiki/Space_habitat
http://en.wikipedia.org/wiki/O%27Neill_Cylinder

The material is then reprocessed by the machine systems into a large
modified O'Neill cylinder.

Each modified O'Neill Cylinder is 6.36 km in diameter and 30 km long -
with a habitable area of 600 square kilometers. Two counter-rotating
cylnders are joined together to form a single pair. A large thin
film parabolic mirror is fixed to the end of these cylinders to
concentrate sunlight to a hyperbolic projector, to project sunlight
along the central axis of each cylinder. A solar power unit along
with industrial unit, is affixed to the dark side of the cylinder.
There additional reaction and industrial mass is stored - with a
machine system setup. At Ceres 100% of the light illuminates the
surface with 850 W/m2. At night the light communicates to the
industrial system to power it. At Earth orbit, 6/7th of the light
goes to the industrial setup during the day, and all the energy goes
to the industrial setup at night.

The mass of each cylinder pair is 2 billion tons, including all
agricultural and industrial systems, and propellant mass. 43,980,000
cylinder pairs are formed and sent to Earth via low energy orbits -
over a 9 month period.

Each of the 800 astronauts are offered a cylinder pair with
replicating industrial system, for staying another 5 years in the
asteroid belt to manage development. Those who return, are parsed 10
to 12 per cylinder pair, for managing orbital operations near Earth
for another 5 years. Those who return to Earth are given $2 million -
bonus.

The cylinders form a ring in sunsynchronous orbit starting at 2,000 km
above the Earth, with 2,314 pairs per orbit, and increasing every 20
km up. Emigres are welcome up to a design density of 100 people per
sq km (farming is done off-colony, along with industry) With 1,200 sq
km per pair, this is 120,000 people per cylinder pair. So, 2314 pairs
per orbit equates to 277 million per ring. 24 rings topping out at
2,480 km above Earth - houses 6 billion people. This is a total of
55,536 cylinder pairs. A little more than 1/1,000th the total
available for shipment to Earth or across the solar system..

The cylinder pairs orient the concentrating dish toward the sun when
in orbit around Earth and stay that way by interaction of the oblate
spinning Earth withthe ring. The ring makes use of ring dynamics
discovered to operate around Saturn, to engineer a safe reliable place
for all 55,536 cylinders to operate.

Durint the 1 year 111 day transit to Earth, seed material, transported
cyrogenically aboard the original nuclear pulse spacecraft, are grown
over the construction period, to a sizeable biomass, and each seeded
cylinder pair grows to maturity during the transit back. Managing the
biomass, and technomass is part of the job of the folks who stay on
planet at Ceres.

While the system uses nuclear power (at this stage) to transport
across the solar system, when on orbit at Earth, or residing on orbit
at Ceres, the system is entirely solar powered.