Article
Circle Launcher and Space Keeper
Circle Launcher and Space Keeper*
Alexander
Bolonkin
1310 Avenue R, #6-F,
Tel/Fax 718-339-4563
E-mail: aBolonkin@juno.com, http://Bolonkin.narod.ru
Abstract
The article describes a new
method and installation for flight in space. This method uses the centrifugal
force of a rotating circular cable that provides a means to launch a load into
outer space and to keep the stations fixed in space at altitudes up to 200
km. The purposed installation may be
used as a propulsion system for space ships and/or probes. This system uses the
material of any space body for acceleration and changes to the space vehicle trajectory.
The suggested system may be also used as a high capacity energy accumulator.
The article contains the theory
of estimation and computation of suggested installations and four projects.
They include: a maximum speed given the tensile strength and specific density
of material, maximum lift force installation, specific lift force in planets
gravitation field, admissible local load, angle and local deformation of
material in different cases, accessible maximum of altitudes of space cabin,
speed which space ship can obtain from installation, power of installation,
passenger elevator, etc. The projects
utilize fibers, whiskers, and nanotubes produced by industry or in scientific
laboratories.
------------------------
* Detail manuscript was presented as Bolonkin paper
IAC-02-IAA.1.3.03 at the Would Space Congress-2002, 10-19 October,
Keywords: Bolonkin launcher, centrifugal space keeper, space launcher, space
launch, planetary ring system.
Nomenclature
a = acceleration,
m/sec
Cf,l = local skin
friction coefficient of two side plate for laminar flow
Cf,t = local skin
friction coefficient of two side plate for turbulent flow
Cc,l = 0.5Cf,l
= local skin friction coefficient of cable
for laminar flow
Cc,t =0.5Cf,t =
local skin friction coefficient of cable for turbulent flow
D = air drag (friction), N
DT = turbulent
drag, N
DL = laminar drag, N
d = cable diameter, m
E = Youngs modulus
Es = energy
storaged by rotary circle pDer 1 kg of the cable, J/kg
F = air friction, N
g = specific
gravity of the planet, m/s2 (for the Earth g=9.81 m/s2 on the altitude H=0)
G = local
load, kg
H = altitude, m
or km
Hmax = maximal attitude of a circle top, m or km
DH
= decrement of an altitude,
m or km
k =d/g =
ratio of tensile stress to a cable density
K = k/107 = strength
coefficient
L = length of a cable, m
M = Max Number
m = throwing mass, kg
mss = mass of a space ship, kg
n = safety factor
N = power ,
J/sec
p = internal pressure on the cable circle, N/m2
P = max.vertical lift force of the vertical cable circle in the constancy gravity field of a
planet, N
P1 = specific lift force of 1
kg of cable mass in a planets gravity field, N
PL = specific
lift force of 1 m of cable in a planets
gravity field, N
Pa = full lift force of a closed loop cable
circle rotated around of a planet, N
Pa,1 = specific lift force of a 1 kg closed loop
cable circle rotated around of a planet, N
Pa,L = specific lift force of a 1 m loop cable
circle rotated around of a planet, when g=0,
N
Pmax = maximum lift force of the rotary
closed-loop circle cable when the gravity g=0,
N
r =
radius of cable cross-section area or a half of cable width, m
R = cable (circular) radius, m
Rmax = maximum cable radius, m
Ro = radius of planet, m
Rv = radius of observation, m
Re* = reference Reynolds Number
S = cross-section area of cable, m2
Sc = cable surface, sq. m
Ss = area of
skin [sq.m] of both plate sides, it means for cable we must take Sc=0.5Ss;
T = air temperature, deg Co
T* = reference (evaluated) air temperature, deg
C
Tw = temperature of wall
(cable), deg C
Te
= temperature of flow, deg
Tmax
= maximum cable thrust, kg
t = time, sec
V = rotary cable
speed, m/s
Va = maximum speed of a closed loop circle around
of a planet, m/sec
Vmin = minimum speed of a closed loop circle, m/sec
Vc = mass speed, m/sec
Vf = speed of falling from an altitude H, m/sec
W = weight (mass) of cable, kg or ton
w = thickness of a boundary layer, m. For cable w
5r
x =
length of plate (distance from the beginning of the cable), m
Dh = cable deformation about a local load, m
Dho = cable deformation about a local load for
the cable circle around a planet, m
DR = increasing the cable radius an internal
pressure, m
DV = additional speed which a space ship gets
from a cable propulsion system, m/sec
a =
angle of cable section, rad
ah
= cable angle to the horizon
about a local load, rad
g = cable density, kg/m3
m = air viscosity. For standard conditions m = 1.72.10-5
m* =
reference air viscosity, kg/m.s
r = air density, for standard condition r =1.225 kg/m3
r* =
reference air density, kg/m3
s = cable tensile stress, n/m2
w = planet angle speed, rad/sec
1. Introduction
The
author offers a new revolutionary method and launch device for: (1) delivering
payloads and people into space, (2) accelerating space ships and probes for
space flight, (3) changing the trajectory of space probes, (4) landing and launching of space ships on space
bodies having small gravity, and (5) accelerating other space apparatus. The
system may be used as a space propulsion system by utilizing the material of
space bodies for propelling space
apparatuses, as well as for storing energy. This method utilizes the
centrifugal force of a closed-loop cable
circle (hoop, semi-circle, double circle). The cable circle rotates at high
speed and has the properties of an elastic body.
The current proposal is a unique
transport system for delivering loads and energy from Earth to the space
station and back. The major difficulties of the Space Elevator are in
delivering the energy to the transport gondola of a space elevator and the fact
that electric wire weighs a lot more than a load bearing cable. The currently proposed space transportation
system solves this problem by locating a motor on the Earth and using
conventional energy to provide the power to move the gondola to the space
station. Moreover the present
transportation system can transfer large amounts of mechanical energy from the
Earth to the Space Station on the order of 3 to 10 Millions watts.
Other non-rocket accesses to
space and applications of this idea are presented in [1]-[19].
2. Description of Circle Launcher
The
installation includes (Fig.1): a closed-loop cable made from light, strong
material (such as artificial fibers, whiskers, filaments, nanotubes, composite
material) and a main engine, which rotates the cable with a fast speed in a
vertical plane. The centrifugal force makes the closed-loop cable a circle. The
cable circle is supported by two pair (or more) guide cables, which connect on
one end to the cable circle by a sliding connection and on the other end to the
planets surface. The installation has a transport (delivering) system comprising the closed-loop load cables (chains),
two end rollers at top and bottom that can have medium rollers, a load engine
and a load. The top end of the transport system is connected to the cable
circle by a sliding connection; the lower end is connected to a load motor. The
load is connected to the load cable by a sliding control connection.
The
installation can have an additional cable for increasing the stability of the
main circle. The transport system can have an additional cable in case the load
cable will damaged.
The
installation works in the following way. The main engine rotates the cable
circle in the vertical plane at a sufficiently high speed where the centrifugal
force becomes large enough so that it lifts the cable and transport system.
After this, the transport system lifts the space station to space.
The
first modification of the Installation is shown on fig.2. There are two main
rollers 20, 21. These rollers change the direction of the cable by 90 degrees
so that the cable travels along the diameter of the circle, thus creating the
form of a semi-circle. It can also have two engines. The others parts are same.
Fig.2. Semi-circle
launcher (space station keeper) and transport system. Notation is same with
fig.1. Semi-circle is same (see right side in Fig.4).
The
Installation can be used for the launch of a payload to outer space (Fig.3).
The load is connected to the cable circle by a sliding bearing through a brake.
The load is accelerated by the cable circle, lifted to a high altitude, and
disconnected at the top of the circle (semicircle).
The
Installation may be used as transport system for delivery people and payload
from one place to other through space (Fig.4).
Fig.3. Launching the space ship (probe) to space by cable
semi-circle. 27 - load.
Fig.4.
Double semi-circle with opposed
speeds for delivery of load to another semi-circle end. 29. Roller.
The
double cable can be used as an excellent launch system, which generates a
maximum speed three times the speed of cable. The launch system has a space
probe (Fig.5) connected to the semi-circular cable and to a launch cable. The
launch cable is connected through a roller (block) to the main cable. We get
the tackle block in which the maximum speed is three times more then a cable
speed.
The
maximum cable speed depends on the tensile strengths of the cable material.
Speeds of 4-6 km/sec can be achieved using modern fibers, whiskers, and
nanotubes (see attached projects).
For
stability, the installation can have guide cables connected to the top of the
cable circle by a sliding connection and to the ground (Fig.6).
Fig.5. Launching
load to space with a triple circle rope speed
by the double semi-circle. Notations
are: 31 - space probe, 32 - engine, 33 - launch cable, 34 - roller, 35 -
connection point of the launch cable, 16,17 - semicircle.
Fig.6. Support
the semi-circle in vertical position (against precession). 38 - guide cable.
The
ship installation may be used as a system for vertical landing and taking-off
(launch) on or from a planet or asteroid because the cable circle can work like
a spring.
The
cable circle of the space ship can be used as a propulsion system (Fig.7). The propulsion system works in the following
way: material from asteroids, or meteorites, or garbage from the ship, are
packed in small packets. The packet is connected to the cable circle. The
circle engine turns on and rotates at a high speed. At the desired point the
pack is disconnected from the circle and, as the throw back mass flies off with
a velocity, the space ship gets an impulse in the requested direction.
The
suggested cable circle or double cable circle can be made around a planet or
space body (Fig.8). This system can be used for suspended objects such as space
stations, tourist cabins, scientific laboratories, observatories, or
re-translators of TV and radio stations.
Figs.7. Using the rope circle as a propulsion system.
Notations are: 98 - garbage, 120 - space ship.
Fig.8. Rope circle around the Earth for 8-10 Space Objects. Notations are: 170
- double circle, 180 drive stations, 182 - guide cable, 186 - energy
transport system, 188 - space station.
This
system works in the following way. The installation has two cable circles,
which move in the opposite directions with the same speed. The space stations are connected to the cable
circle through the sliding connection. They can move along the circle in any
direction when they are connected to one of the cable circles through a
friction clutch, transmission, gearbox, brake, and engine. They can use the
transport system in figs.1 and 2 for climbing to or descending from the
station. Because energy can be lost from friction in the connections, the
energy transport system and drive rollers transfer energy to the cable circle
from the planet surface. The cable circles are supported at a given position by
the guide cables (see Project No. 2). No towers for supporting the circle cable
are needed.
The
installation can have a system for changing the radius of the cable circle
(Fig.9). When an operator moves the tackle block, the length of the cable
circle is changed and the radius of the circle is also changed.
Fig.9. Radius
system for changing a radius of the rope circle. Notations are: 230 - system
for radius control. 234 - engine, 236 - mobile tackle block, 244 - transport
system, 246 - engine, 248 - circle, 250 - guide cable.
With
the radius system the problem of creating the cable circle is solved very
easily. Expensive rockets are not necessary. The operator starts with a small
radius near the planet surface and increases it until the desired radius is
achieved. This method may be used for making a semi-circle or double
semi-circle system.
The
small installation may be used as a crane for construction engineering,
developing building, bridges, in the logging industry, and so on.
The main advantage of the proposed launch
system is a very low cost for the amount of payload delivered to space and over
long distances. Expensive fuels, complex control systems, expensive rockets,
computers, and complex devices are not required. The cost of payload delivery
to space would drop by a factor of a thousand.
In addition, large amounts of payloads could be launched into space (on
the order of a thousand tons a year) using a single launch system. This launch
system is simple and does not require high-technology equipment. The payloads
could be delivered to space at production costs of 2 - 10 dollars per kg (see
computations in the attached projects).
2.1. Cable problem
Twenty years ago, the mass of the required cable would not allow this
proposal to be possible. However,
todays industry widely produces artificial fibers which have tensile strength
3-5 times more than steel and density 4-5 times less than steel. There are experimental fibers (whiskers),
which have tensile strength 30-100 times more than steel and density 2 to 5
times less than steel. For example,
Galasso [3], p.158 quotes data for a
fiber (whisker) CD, which
tensile strength s = 8000
kg/mm2 and density (specific gravity) g = 3.5 kg/m3.
The mechanical behavior of nanotubes also has
provided excitement because nanotubes are seen as the ultimate carbon fiber,
which can be used as reinforcements in advanced composite technology. For
example, Carbon nanotubes (CNT) have a tensile strength of 2×1011
Pa (20,000 kg/mm2) and a
Youngs modulus over 1012 Pa (1999).
The theory predicts tensile strength up 1012 Pa (100,000 kg/mm2) and Young module
of 1÷5×1012
Specific strength
(strength/density) is important in the design of the space circle and elevator.
Nanotubes have a specific strength at least 2 orders of magnitude greater than
steel. Traditional carbon fibers have a specific strength 40 times that of
steel. Whereas nanotubes are made of graphite carbon, they have good resistance
to chemical attack and have high terminal stability. Oxidation studies have
shown that the onset of oxidation shifts by about 1000 C or more in
nanotubes compared to high modulus graphite fibers. In a vacuum or reduced
atmosphere, nanotubes structures will be stable to any practical service
temperature.
The price of the whiskers SiC
produced by Carborundun Co. with s = 20,690 MPa (2069 kg/sq.mm), g =3.22 g/cc were 440 $/kg in 1989.
Below the author provides a brief overview
of research information regarding the proposed fibers, whispers, and
nanotubes. In addition, the author has
also solved additional problems, which appear in potential projects and which
can look as difficult as the proposed space transportation technology.
3. Theory of Circle Launcher
Take a small
part of a rotary circle and write the equilibrium
2SRagV2/R
= 2Ss
sina
.
When a0, the relationship between
maximum rotary speed and tensile strength of a closed-loop circle cable is
V=(s/g)1/2 =k1/2 ,
(1)
Results of this computation are presented in
fig.10.
Maximum lift force Pmax of the rotary
closed-loop circle cable when the gravity g=0
equals the cable tensile force:
Pmax=
2V2gS = 2sS . (2)
The maximum vertical lift force P of the vertical cable circle in the
constancy gravity field of a planet equals the lift force (2) minus the cable
weight
P=2S(s - pRgg) .
(3)
The maximum lift force P of the double semi-circle cable in the gravity field of a planet
is
P=4S(s - 0.5pRg g) .
(3a)
Approximately one quarter of this force can
be used. The result of computation is presented in fig.11.
Figs.10-11.
The minimum speed of the cable circle can be
given from (3) and (1) for P = 0
. (4)
Example:
For R = 0.15 m, the minimum speed is
2.15 m/sec; for R = 50 km, the
minimum speed is 1241 m/sec.
The minimal speed of the double semi-circle
can be given from (3a) and (1) for P =
0
. (4a)
Specific lift force of one kg of cable mass P1 in a planets gravity field equals the lift force
(3) divided by the cable weight 2pRSg . For a conventional circle
P1=(s/pgR) - g . (5)
While for a double semi-circle
P1=(2s/pgR) - g . (5a)
The specific lift force PL of one meter of
cable in a planets gravity field equals the lift force (3),(3a) divided
by the cable length, respectively
PL = S[(s/pR)
- gg] ,
PL = 2S[(s/pR)
- 0.5gg] . (6),(6a)
The length of a cable L, which
supports the given local load G is
L = G/PL. . (7)
The cable angle, ah, to the horizon about a local load equals (from a
local equilibrium)
ah = argsin(G/2sS) . (8)
Cable deformation about a local load
(decreasing of altitude) for a cable semi-circle in a planet gravitys field
approximately equals
Dh @ GL/12sS . (9)
Cable deformation about a local load for the
double cable circle around a planet in
space is
. (10)
The internal pressure on the cable circle we
can derived from equilibrium condition. The result is
p = p rs/2R . (11)
Increasing the cable radius under an
internal pressure
DR = gV2R/E
. (12)
Maximum cable radius (maximal cable top) in a
constant gravity field can derived from the equilibrium of the lift force and a
cable weight:
a) Full circle (from (3))
Rmax = s/pgg , Hmax=2Rmax . (13)
b) Semi-circle (from (3a))
Rmax = 2s/pgg , Hmax=Rmax . (13a)
The result of computation is presented
in fig.12.
The maximum cable radius in a variable
gravity field of a rotating planet can be found from the equation of a circle
located on equator flat)
. (14)
The maximum speed of a closed-loop circle
rotated around a planet can be found
from the equilibrium between centrifugal and a gravity forces
Va = [(s/g) + Rg]1/2 . (15)
The results of computation are presented in
fig.13. The minimum Va = (Rg)1/2
occurs when
k=s/g=0.
Figs.12-13.
The lift force Pa of a double closed loop cable circle rotated around a
planet can be found from equilibrium of a small circle element
Pa=4pSg (Vs2
- k - Rg). (16)
The full lift force of a double closed loop
cable circle rotated around a planet is (multiple p from (11) by a cable area 4pRr) or
Pa = 2psS . (16a)
The results of computation are presented in
fig.14.
The specific lift force of a one kg closed loop cable circle rotated
around a planet can be found from Eq.(16), by
dividing by cable weight
Pa,1 = s/gR . (17)
The specific lift force of a one meter
closed loop circle around a planet in space, when g = 0, can be found from Eq. (16), if it is divided by the cable
length
Pa,L = Ss/R . (18)
We can derive from momentum theory an
additional speed, DV, which a space ship (Fig.7) gets from a cable
propulsion system
DV = Vcm/(mss-m) . (19)
The results of computation are presented in
fig.15.
Fig.14-15.
The speed of falling from an altitude H
Vf
= (2gH)0.5 . (20)
The energy, Es , stored by a
rotary circle per 1 kg of the cable mass can be derived from the known equation
of kinetic energy. The equation is
Es = s/2g . (21)
The result of computation are presented
in fig.16.
Fig.16.
The radius of observation versus altitude H [km]
over the Earth is approximately
Rr
= (2RoH + H2)0.5 [km]
, (22)
where Earth radius Ro=6378 km. If H=150 km, then Rr = 1391 km.
Estimation of Cable Friction Due to the Air
This
estimation is very difficult because there is no experimental data for air
friction of an infinitely very thin cable (especially at hypersonic speeds). A
computational method for plates at hypersonic speed was used, described in the
book [4], p.287. The computation is made
for two cases: laminar and turbulent boundary layer.
The results compare very
differently. The maximum friction is for turbulent flow. About 80% of the
friction drag occurs in the troposphere (from 0 to 12 km). If we locate the cable
end on a mountain at an altitude of 4 km the maximum air friction decreases by
30%. So the drag is calculated for three cases: when the cable end is located
on the ground H=0.1 km over sea level, H=1
km and when it is located on the mountain at H = 4 km (2200 ft).
The major part of cable will have the
laminar boundary layer because a small wind will blow away the turbulent layer
and restore the laminar flow. The blowing of the turbulent boundary layer is
studied in aviation and is used to restore laminar flow and decrease air
friction. The laminar flow decreases the friction in hypersonic flow by 280
times! If half of cable surface has a laminar layer it means that we must
decrease the air drag calculated for full turbulent layer by a minimum of two
times.
Below the equations from
(T*/T) =1 + 0.0032M2 + 0.58(Tw/Te
-1) ; m*=1.458.10-6T*1.5/(T*+110.4)
; r* = rT/T*;
Re*=r*Vx/m* ; Cf,l
= 0.664/(Re*)0.5 ; Cf,t=0.0592/(Re*)0.2
; Cc,l = 0.5Cf,l , Cc,t =0.5Cf,t ,
DL = 0.5Cc.lr*V2Sc ; DT = 0.5Cc.tr*V2Sc ; D = 0.5(DT+DL)
. (23)
Apply the above theory to the double
semi-cycle case. Approximate the atmosphere density by exponential equation
, (24)
where ro=1.225 kg/m3, b=-0.00014,
h is the altitude [m]. Then the air
friction drag is
(25)
where DT,L and Cc,l,t are turbulent and
laminar drag and drag coefficient respectively, a1 is angle of cable element to the horizon. The full drag is D = 0.5(DT+DL). The
results of computation are presented in Fig.17.
The simplest formula of air friction F
is
F = mVSc/w . (26)
The required power, N, equals
N = DV
. (27)
The results of computations using
Eq.(27) are presented in fig.18.
Fig.17-18.
4.
Case Studies
Consider the following
experimental and industrial fibers, whiskers, and nanotubes.
1. Experimental carbon nanotubes CNT (Carbon
nanotubes) have a tensile strength of 2×1011 Pa (20,000 kg/mm2),
a Youngs modules of over 2×1012
Pa and a specific density g =1800 kg/m3 (2000 year)[6]. For a safety factor of n=2.4, we can use σ =2×1011 Pa (s = 8300 kg/mm2
= 8.3.1010 n/m2 ) and g=1800 kg/m3,
or k = (s/g)=46×106,
K = 4.6.
2. Whiskers CD have σ =8×1010 Pa (s = 8000 kg/mm2), and g = 3500 kg/m3
(1989)[3]. We take for computations: s = 7000 kg/mm2, g = 3500 kg/m3, k = sg = 20x106 , K = 2.
3. Industrial fibers have s = 500-650
kg/mm2 and g = 1800 kg/m3,
or sg = (2,78
3.6)x106, K= 0.278 - 0.36.
Some other experimental whiskers and
industrial fibers are listed in Table 1. The planet data is in Table 2.
Tables 1-2.
4.1. Project 1
Space Station for Tourists
or a Scientific Laboratory at an Altitude of 140 km (figs.1-6)
The closed-loop cable is a
semi-circle. The radius of the circle is 150 km. The Space Station is a cabin
with a weight of 4 tons (9000 LB) at an altitude of 150 km (94 mils). This
altitude is 140 km under load.
The results of computations for
three versions (different cable strengths) of this project are in Table 3.
Table 3.
Economic Estimations of these projects for Space
Tourisms.
Take the weight (mass) of the
tourist cabin as 2 tons (it may be up 4 tons), and the useful payload as 1.3
tons (16 tourists plus one operator). Acceleration (braking) is 0.5g (a
=5 m/s). Then the time to climb and descend will be about 8 minutes (H=0.5at2) and 20 minutes for
observation at an altitude 150 km. The common flight time will be 30 minutes.
The passenger capability will be about 800 tourists per day.
Let us to use the following
equation for estimation of delivery cost, C
:
, (26)
where: I = installation cost,
$; n1 = installation life
time, years; M = yearly maintenance,
$; N =DV - engine power, J/sec; t - year time (t =3600.24.365), sec; c = fuel cost, $/kg; q =
fuel heat capability, J/kg (for benzene q=43.106
, J/kg, for coal q=20.106
; for natural gas q=45.106);
h = engine
efficiency, h = 0.2 - 0.3; n2 = number of
tourist per day, people/day; n3
= number working days in year.
Let us take for variant 3: I=$100 millions; n1 = 10 years; M
= $2 millions in year; N =DV - engine
power, J/sec, where D=50,000 N, V=1670
m/s; t
=3600.24.365=31.5.106 sec; c
= 0.25, $/kg; q=43.106
, J/kg; h = 0.25; n2 =400 people; n3 = 360 . Results of
computations are presented in fig.19.
Fig.19.
Then the production cost of a space trip
for one tourist will be equal to $508 (about 84% of this cost is the cost of
benzene). This cost is $363 for variant 2. If the cost of the trip ticket will
be $100 more than the production cost, the installation will give a profit of
about $14-49 million per year. This profit may be larger if we design the
installation especially for tourism. If our engines use natural gas (not
benzene), the production cost decreases by the same ratio that gas cost is to
benzene.
Discussing of the project 1.
1)
The first variant has a cable diameter of 1.13 mm
(0.045 inch) and a general cable weight of 1696 kg (3658 LB). It needs a power
(engine) station to provide from 102 to a maximum of 146 MW (the maximum amount
is needed for additional research).
2)
The second variant need the engine power from 49 to
76 MW.
3)
The third variant uses a cable with tensile strength
near that of current fibers. The cable has a diameter of 11.3 mm (0.45 inch)
and a weight of 170 tons. It needs an
engine to provide from 83.5 to 117 MW.
The systems may be used for launching (up to
1 ton daily) satellites and interplanetary probes. The installation may be used
as a relay station for TV, radio, and telephones.
4.2. Project 2
Semi-circle of a Radius 1000 km (625 miles)(Fig.4) for
Delivering Passengers to a Distance of 2000 km (1250 miles) Through Space
The two closed-loop cable is a semi-circle.
The radius is 1000 km. The Space cabin has a weight of 4 tons (9000 LB). The
maximum altitude is 1000 km. The results of Computation for two versions are in
Table 4.
Table 4.
Estimation of economical efficiency
Let us take the cost of installation
and service as the same as the previous project. Then the delivery cost of one
passenger will be same (see Fig.19). If a ticket is marked up 50 dollars more
(from $130 to $180 if there are 2000 passengers), then the profit will be about
18 million dollars per year.
Discussing of Project 2.
Version 1 has a cable diameter of 1.13 mm
(0.047 inch), a cable weight of 11.3 tons, and has a passenger capacity of 2000
passengers per day in two directions. The distance is 2000 km (1250 miles) and
delivery time 27 minutes.
These transport systems may be
used for launching (weight up to 1 ton) satellites.
This system may be the optimum
way to travel between two countries that are separated by a third country which
does not have an air corridor for conventional airplanes, or is an enemy
country. The suggested project goes into outer space (H=1000 km) and out of the atmosphere of the third country.
4.3. Project 3
Circle Around the Earth at an Altitude of 200 km (125 miles) for 8-10 Scientific
Laboratories (fig.8)
The closed-loop cable is the
circle around the Earth at an altitude H
of 200 km (125 miles). The radius is 6578 km. The Space Stations are 8-10
cabins with a weight of 1 ton (2222 LB)).
Results of Computation for
three versions are in Table 5.
Table 5.
Discussing of Project 3.
The variant 3 using current
fibers (s =500 kg/sq.mm; 5000 MPa) has a cable diameter of 3.6 mm
(0.15 inch), a cable weight 744 tons, and can keep 10 Space Stations with
useful loads (200-500 kg) for each Station at an altitude of 180 km (112
miles). This may also be used for launching small (up to weight 200 kg)
satellites.
4.4. Project 4
Using the
As presented in the main text the suggested
system may be used as a space ship launch system, as a landing system of space
ships on planets and asteroids, or as a delivery system for people and loads
from a space ship to the planets, asteroids surface and back without landing
the ship.
Below we consider an application
of this system as a propulsion system used any
mass (for example, meteorites, asteroid material, ship garbage, etc.) for
creating of ship thrust. The offered system may be used also for storing of energy.
Let us suggest that a space ship
has a nuclear energy station. The ship has a lot of energy. However, the ship
can not use this energy efficiently for thrust because known ion thrusters
(electric rocket engines) produce only small amounts of thrust (from grams to
kg). Consequently any trip would
require a lot of time (years). Rocket engines require a lot of expensive fuel
(for example, liquid hydrogen for a nuclear engine) and oxidizer (for example,
liquid oxygen), which increases greatly launch costs, the ship mass,
requirements for low temperatures and difficulties for storage.
The suggested system allows any
material (mass) to be used for imparting speed to a ship. For example, let the
space ship have the cable system made from carbon nanotubes (tensile
strength 8300 kg/mm2 and
density 1800 kg/m3). It means [Equ.(1)] the cable system can have a
maximum speed of 6800 m/s (Table 3, column 5). The system can throw off mass at
this speed in any direction and provide thrust for the space ship. The specific
impulse of the cable system 6800 m/s, is better than the specific impulse of
any modern rocket engine. For example, current rocket engines have 2000-2500
m/s (solid fuel), 3000-3200 m/s (liquid kerosene - oxygen fuel), and up to 4200
m/s (an hydrogen - oxygen fuel). If the ship takes 50% of the ships mass in
asteroid material, the space ship can get an additional speed 6800 m/s [see
Equ. (19)]. The space ship can also use for thrust any of the ships garbage.
As energy storage system the suggested
cable system allows 23 MW of energy for storage per every 1 kilogram of a cable
[see Equ.(21)]. It is more than any current 1 kg of a full fuel (fuel and
oxidizer).
5. Discussing, Summary, and
Conclusions
The offered method and installations promise
to decrease a launch cost by a factor of a thousands. They are very simple and
inexpensive. As any method, the suggested method requires further detailed
theoretical research, modeling, and development.
Science laboratories have whiskers and nanotubes
which have high tensile strength. The theory shows that these values are only
one tenth of the theoretical level. We must study how to get a thin cable, such
as the strings or threads we produce from cotton or wool, from whiskers and
nanotubes. About 300 kg nanotubes will be produced in the
The fiber industry produces
fibers, which can be used for some of the authors projects at the present
time. These projects are unusual (strange) for specialists and people now, but
they have huge advantages, and they have a big future. The government must
award scientific laboratories and companies who can get a cable with the given
performances for a reasonable price, who research and development perspective
methods.
References
1Space
technology & Application. International Forum, 1996-1997,
2 D.V.
Smitherman, Jr., Space Elevators, NASA/CP-2000-210429, 2000.
3 F.S. Galasso, Advanced
Fibers and Composite, Gordon and Branch Scientific Publisher,
1989.
4 J.D. Anderson, Hypersonic and High Temperature Gas Dynamics,
McCrow-Hill Book Co., 1989.
5 Carbon and High Performance Fibers, Directory, 1995.
6 J.I. Kroschwitz, (Ed.) Concise Encyclopedia of Polymer Science and Engineering, 1990.
7 M.S. Dresselhous, Carbon Nanotubes, Springer, 2000.
8 A.A. Bolonkin,
Centrifugal Keeper for Space Stattions and Satellites, JBOS, Vol.56, No.9/10,
2003, pp.314-327.
Figure
Captures
Fig.2.
Semi-circle launcher (space station keeper) and transport system.
Notation is same with fig.1. Semi-circle is same (see right side in Fig.4).
Fig.3. Launching the space ship (probe) to space by
cable semi-circle. 27 - load.
Fig.4. Double semi-circle with opposed speeds for
delivery of load to another semi-circle end. 29. Roller.
Fig.5. Launching load to space with a triple circle rope speed by the double semi-circle. Notations are: 31 - space probe, 32 - engine, 33 -
launch cable, 34 - roller, 35 - connection point of the launch cable, 16,17 -
semicircle.
Fig.6. Support the semi-circle in vertical position (against precession).
38 - guide cable.
Fig.7. Using the rope circle as a propulsion system. Notations are: 98 -
garbage, 120 - space ship.
Fig.8. Rope circle around the Earth for 8-10
Space Objects. Notations are: 170 - double circle, 180 drive
stations, 182 - guide cable, 186 - energy
transport system, 188 - space station.
Fig.9. Radius system for changing a radius of the rope circle. Notations
are: 230 - system for radius control. 234 - engine, 236 - mobile tackle block,
244 - transport system, 246 - engine, 248 - circle, 250 - guide cable.
Fig.10. Maximum cable
speed versus admissible specific cable stress.
Fig.11. Maximum lift force
of cable S=1 mm2 versus stress.
Fig,12. Maximum radius of
Earth semi-circle versus specific cable stress.
Fig.13. Maximum speed of a
closed-loop circle around a planet,
Fig.14. Full lift force of
the closed-loop cable circle rotated around a planet.
Fig.15. Relative speed of
space ship versus relative throwing mass.
Fig.16. Storage energy of
1 kg of the cable.
Fig.17. Estimation of the friction air drag [tons]
versus cable speed [km/s] and initial altitude [km] for double semi-circle
keeper.
Fig.18. Estimation of the drive power [kW] versus
cable speed [km/s] and initial altitude [km] for double semi-circle keeper.
Fig.19. Estimation of the production cost per one
tourist versus number of tourist per day for the installation cost 50, 100,
150, 200, 250 millions
Table 3.
Results of Computation for Project 1.
Table 4. Result of Computation for Project 2.
Table 5. Result of Computation for Project 3.
Table 1. Properties
of Some Relevant Materials.
Material Tensile Density, Tensile Density,
Strength, g/cc strength, g/cc
Whiskers kg/mm2
Fibers kg/mm2
AlB12 2650 2.6 QC-8805 620 1.95
B 2500 2.3 TM9 600 1.79
B4C 2800 2.5 Thorael 565 1.81
TiB2 3370 4.5 Allien
1 580 1.56
SiC 1380-4140
3.22 Allien 2 300 0.97
Reference [4]-[7].
Table 2. Planet Data
Planet Radius,
106 m ` Gravitation, m/s2 Angle speed 10-6
, rad/sec
Earth 6.378 9.81 72.685
Mars 3.390 3.72 71.06
Moon 1.737 1.62 2.662
Table 3. Result of Computation for Project 1.
# variants s, kg/mm2 g, kg/m3 K=sg /107 Vmax,
km/s
Hmax, km S mm2
1 2 3 4 5 6
7
--------------------------------------------------------------------------------------------------------------------------------
1 8300 1800 4.6 6.8 2945 1
2 7000 3500 2.0 4.47 1300 1
3 500 1800 0.28 1.67
180 100
Pmax[tons] G kg Lift
force kg/m Loc.load kg L
km a0 DH km
8 9 10 11 12 13 14
---------------------------------------------------------------------------------------------------------------------
30 1696 0.0634 4000 63
13.9 5.0
12.5 3282 0.0265 4000 151 16.6 7.2
30.4 170x103 0.0645 4000 62 4.6 0.83
Cable Thrust Cable drag
Cable drag Power MW PowerMW
Max.Tourists
Tmax kg H=0
km, kg H=4
km, kg H=0 km H=4 km men/day
15 16 17 18 19 20
-------------------------------------------------------------------------------------------------------------
8300 2150 1500 146 102 800
7000 1700 1100 76 49 400
50000 7000 5000 117
83.5 800
The column numbers are: 1)
the number of the variant; 2) the
permitted maximum tensile strength [kg/mm2]; 3) the
cable density [kg/m3]; 4) the
ratio K=s/g 10-7;
5) the maximum cable speed [km/s] for a given tensile strength; 6) the maximum altitude [km] for a given
tensile strength; 7) the cross sectional
area of the cable [mm2]; 8) the
maximum lift force of one semi-circle [ton];
9) the weight of the two semi-circle cable [kg]; 10) the lift force of one meter of cable
[kg/m]; 11) the local load (4 tons or 8889 LB); 12) the length of the cable required to
support the given (4 tons) load [km];
13) the cable angle to the horizon near the local load [degrees]; 14) the change of altitude near the local
load; 15) the maximum cable thrust
[kg]; 16) the air drag on one semi-circle
cable if the driving (motor) station is located
on the ground (an altitude H=0)
for a half turbulent boundary layer; 17)
the air drag of the cable if the driving station is located on a mountain at H=4 km; 18) the power of the driving
stations [MW] (two semi-circles) if located at H=0; 19) the power of the driving stations [MW] if
located at H=4 km; 20) the amount of
tourists (tourist capacity) per day (0.35 hour in Station) for double
semi-circles.
Table 4. Result of
Computation for Project 2.
s kg/mm2 g kg/m3 V km/s S mm2 W
tons Pmax tons Pus kg Men/day
Time[min]
1 2 3 4 5 6
7 8 9
----------------------------------------------------------------------------------------------------------
8300
1800 4.6
1 11.3 11 3000
2000 27
7000 3500 2.0
1 20.2 3 750 500 27
Where in the columns are:
1) Tensile strength [kg/mm2]; 2) Density [kg/m3]; 3) Cable
speed [km/s]; 4) Cross sectional cable area [mm2]; 5) Cable
weight of two semi-circles [tons]; 6) Maximum cable lift force [tons]; 7)
Useful local load [kg]; 8) Maximum
passenger capability in both directions [people/day]; 9) Time of flight in one direction.
Table 5. Result of Computation for Project 3.
# s g V
kg/mm2
kg/m3 km/s mm2 [tons]
[tons] [kg/km]
[degree] [km]
-----------------------------------------------------------------------------------------------------------------------
1 2 3 4
5 6 7
8 9 10
-----------------------------------------------------------------------------------------------------------------------
1 8300 1800
10.53 1 52.1 74.4
1.26 3.45
12.5
2 7000 3500
9.19 1 44 145
1.06 4.1 17.2
3 500 1800 8.06 10 31.4
744 0.76
5.74 35
The numbers note: 1)the number of the
variants; 2)Tensile strength [kg/mm2]; 3) Cable
density [kg/m3]; 4) Cable speed [km/s];
5) Cross sectional cable area [mm2]; 6) Maximum
cable lift force [tons]; 7) Cable weight [tons]; 8) Lift force of 1 km of cable
[kg/km]; 9) Cable angle to the horizon near a local load [degrees]; 10) Change
(decreasing) of the altitude under a local load 1 ton [km].