The GEOS cable boom mechanism allows the controlled deployment of a 20 m long cable in a centrifugal force field. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface

Schmidt, B. K.

Suttner, K.

English

NASA Technical Reports Server

N79-21389
GEOS - 20 m Cable Boom Mechanism
By Giinter K. Schmidt and Klaus Suttner
Dornier System GmbH - Germany
ABSTRACT
The GEOS Cable Boom Mechanism allows the controlled deployment of a 20 m long cable in a
centrifugal force field. In launch configuration the flat cable is reeled on a 240 mm diameter drum.
The electrical connection between the rotating drum and the stationary housing is accomplished via
a Flexlead positioned inside the drum. Active motion control of this drum is achieved by a self
locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by
an optical length indicator, sensing black bars engraved on the cable surface.
This paper describes the design, development, and testing of the operational modules.
Drum with Cable and Flexlead
Worm gear drive with stepper motor
and
Deployment length indicator
1. INTRODUCTION
GEOS is a scientific geostationary satellite spinning at 10 rpm in orbit. The payload consists of
seven experiments with approximately 30 modular units. Most of the experiment probes and
sensors had to be positioned at specific distances from the S/C surface to reduce body interference.
The location and orientation requirements of these probes led to the design of a Boom and
Mechanism Subsystem comprising of 8 different booms and 5 mechanisms. Two of the booms are
20 m long Cable Booms serving two active electronic sensors at their tips. During launch these
sensors are stowed tangentially on the spacecraft surface in experiment containers. When released,
these containers are opened to allow the sensors to swing out. The swinging motion is damped by a
release system and a tubular damper. This release system is called the "Experiment Release
Mechanism" and was presented by Mr. G. Bring from ESA at the May 76 Symposium in F rascati,
Italy. (Ref. 1). After the release motion is damped out, the two boom cables are radially deployed
by their "Cable Boom Mechanisms", which are positioned inside the Spacecraft below the lower
equipment shelf.
2. BASIC DESIGN REQUIREMENT
Deployment length is 20 m.
Deployment accuracy is +_5 cm.
I ntermittant synchronous deployment in 10 cm steps and general start-stop mode.
Test retractability and limited retractability in orbit.
All bearings are dry lubricated.
Maximum power consumption is 35 W.
Maximum height is 270 mm.
Magnetic cleanliness has to be achieved.
1 Dipole and 10 connection lines for signals and power between tip sensor and S/C.
Operation in vacuum between -20 and +55°C.
153 Precedingpageblank
https://ntrs.nasa.gov/search.jsp?R=19790013218 2020-03-20T18:54:21+00:00Z
3. FUNCTIONAL DESIGN CHARACTERISTICS
A brief description of the Cable Boom Mechanism design is shown in Fig. 1. Additional details are
provided in a Design Study Report. (Ref. 2). The following will highlight the more interesting
functional groups: -
Cable and Flexlead
Worm gear drive
Stepper motor
Optical deployment sensor.
4. CABLE AND FLEXLEAD
For GEOS a flat cable of 1,5 x 7,3 mm cross section, consisting of five pairs of signal- and power
leads AWG 36 and one AWG 24 central load wire with 60 pf/m lead capacitance was used. (Fig. 2).
The cable was braided with twelve AWG 42 conductors and covered with gold plated Kapton tape.
One side was painted with 2 x 6 mm black bars spaced at 10 mm intervals for the optical length
indications. The cable was manufactured by HABIA, Sweden. Further details and dynamics of this
cable are provided in Ref. 3.
Major problems were created by Use of the Kapton tape. Due to poor gold adhesion of the standard
tape, the gold had to be vapor deposited in an ultra high vaccuum chamber. Following this process,
a double sided self adhesive scotch tape was applied to the inner surface of the gold plated Kapton
tape. The tape was then wrapped around the braided cable body.
The Flexlead which is attached to the stationary housing is positioned within the cable drum. It is
reeled on the centre hub in the stowed configuration and unreeled onto the inner surface of the
worm wheel fixation ring in the deployed configuration.
The Flexlead cable which electrically connects the rotating drum and the stationary housing, is a
flat teflon cable of 0,5 x 14 mm cross section with sixteen AWG 30 leads. The cable complied with
specified capacitance and impedance values. This cable was also developed and manufactured by •
HABIA, Sweden.
To assure reliable performance, one side of the Flexlead cable is required to be as flat as possible to
reduce lateral forces between the layers during unreeling. The results of tests and post test analyses
led to a design shown in Fig. 3.
The geometrical lay-out of the Flexlead is based on the following equations.
I
I
1. L=dm.W.Tr
2. dmi = d i + W i . S
dma = da + W a . S
3. n = W i - Wa
L = Flexlead length
W i = number of inner windings
Wa = number of outer windings
n = number of revolutions
S = Flexlead cable thickness
d i -- inner diameter
da = outer diameter
154
using the dimensionless Factors _ttt. 6"S
the following Flexlead equation can be derived:
a) Range of definition: d i _<d _< da
p/
£ L =&
=
b) differentiated for maxima:
= +I -
The Flexlead Diagram, see Fig. 4, includes equations (a) and (b). For GEOS the following para-
meters wereused: (j,= 6 6" = 5_ _'_ = q_'_¢ _1_ =_
A Flexlead cable length of 12 m for 37 reel revolutions was derived from this diagram. A coiling
factor of 0,9 was used.
The Flexlead was built and tested according to these parameters and performed successfully.
5. WORM GEAR DRIVE
For a cable boom system, a worm gear drive has fundamental advantages. Since cable booms deploy
by the action of centrifugal force induced by the spinning satellite, deployment forces need not be
provided. The task of the gear in this case is to prevent uncontrolled deployment. This can be
obtained in a very efficient way with a self locking worm gear. The lower the self locking efficiency,
the lower the torque requirement at the worm shaft necessary to control deployment motion. Thus,
deployment control can be accomplished with a very small motor.
However, these operational conditions with the use of dry lubrication require a very careful design
of the worm gear configuration and material selection. Of considerable importance are stable
friction conditions between worm and worm wheel.
Several material combinations were tested in a special test to determine their frictional behaviour as
a function of operation time. Excellent results were obtained with a titanium worm and a
HOSTAFLON worm wheel. In actuality, the initial friction of this combination is rather high.
However, the friction reduces after a run-in period to a very constant value. A friction value of
about # = 0,16 to 0,18 was determined as the result of these friction investigations. Considering this
value and the configuration data the gear data was thereby chosen:
pitch 2 mm
gear ratio 100
pitch angle 6,33 °
With this gear design and the available torque of the stepper motor, an operational range of V = 0,11
to 0,25 was achieved, providing a sufficient safety margin. The design parameters for the worm gear
can be obtained from the worm gear Nomogram (Fig. 5) which was specifically developed for this
drive assembly.
Full conformity between design and actual hardware was demonstrated during qualification testing.
155
6. THE MOTOR
A size 11, 4 phase variable reluctance stepper motor was chosen to drive the Cable Boom
Mechanism.
Even considering the poor efficiency of these motors, they provide several important advantages:
Small rotational speed without gear head and speed variation capability
High calculated reliability due to minimal amount of mechanical parts
Low residual magnetism following switch off
Digital servo electronics
Simple electronic synchronisation of several motors.
The motors, used for the GEOS Cable Boom Mechanisms, were specially developed by SAGEM,
France. These stepper motors can provide a starting torque of more than 25 Nmm. The length of
the housing is 52 mm and its mass 125 g. The motor has a step angle of 15° and runs with 12 Hz
(speed A) and 48 Hz (speed B).
The motor is operated by a Motor Control Electronic (MCE), which functions in several deploy-
ment modes, with a synchronous four phase driver signal for two stepper motors.
7. DEPLOYMENT LENGTH INDICATOR
The purpose of the deployment length indicator is to measure the deployed length of the boom
cable. It consists of the following:
the optical head and
the processing electronics.
The optical elements of the optical head consist of a matched pair of light emitting diode and photo
transistor. The geometrical arrangement of both of these devices assure that the maximum possible
amount of emitted light is reflected into the photo transistor. Reflectance is achieved by a gold
plated cover tape on the Boom Cable, which passes under the optical head. Maximum reflection
occurs when the optical axes of the light emitting diode and the photo transistor intersect in the
plane of the cover tapes. The gold plated cover tape is marked with a periodic pattern of non-
-reflecting black bars, that are spaced 10 mm apart and are 2 mm wide. (Fig. 6).
The processing electronics generate a counting pulse when a bar has passed the optical head in either
direction. However, no counting will occur if the bars are oscillating back and forth in the cable axis
direction at amplitudes of less than 5 mm. To achieve this count deletion, a second optical element
in the optical head is displaced from the first by 5 mm in the cable axis direction. Using the outputs
of both optical elements, the counting pulses due to cable longitudinal oscillations are automatically
suppressed by the processing electronics. For reliability purposes, the arrangement of the two
optical elements is duplicated in the optical head, the outputs of the redundant photo transistors
being O R-gated.
156
8. TESTING
The Cable Boom Mechanism as a unit was successfully tested at development, qualification and
acceptance levels. The following environmental tests were carried out at unit level:
Vibration tests - sinus and random
Thermal - Vacuum test between -30 ° and +60°C at a pressure less than 10 -7 Torr
Electromagnetic Cleanliness Tests
The environmental tests were accompanied by unit performance tests. The most significant and
comprehensive performance test was accomplished by means of a special Unit Test Rig.
This Unit Test Rig consists of an electronic Unittester simulating the electrical interfaces to the
Satellite, and a test fixture simulating the mechanical orbit conditions. It also allows the simulation
of any required orbital deployment load characteristic.
The deploying cable is stored on a drum which simulates the cable load by means of a controllable
torque motor. The torque profile is provided and monitored via the Unittester. The Cable Boom
Mechanism itself is mounted on a base plate supported by bar springs. Strain gauges positioned at
the bar springs measure the cable loads, applied to the drum.
The test fixture is very compact and enables simulated Cable Boom deployments also in small test
chambers. In addition to these unit tests, comprehensive component tests were carried out with the
Boom cable, and cable marks, Flexlead cable, stepper motor, worm gear, optical head and control
electronics.
9. CONCLUSIONS
For the GEOS satellite a 20 m Cable Boom Mechanism was designed, developed and qualified. This
effort was sponsored by the EUROPEAN SPACE AGENCY as part of the GEOS Development
Contract.
The layout of the Flexlead and the worm gear required rather careful consideration. Problems
associated with the adhesion of the gold layer and the black marks on the gold surface as well as
with the optical head had to be solved.
However, due to the modular configuration and the availability of a parametric design lay-out and
computer programs, the application of this mechanism is not limited to a 20 m cable, but can be
easily adapted to other configurational requirements and applications. Longer and heavier cables
can be deployed and retracted with a stronger motor for instance.
The application range of this mechanism covers 100 and more metres deployment lenght. If neces-
sary, a deployment accuracy of less than 1 cm can be achieved.
10.
1)
2)
3)
REFERENCES
ESA SP 117, Presentation held in Frascati, Italy 24-26 May 1976 by G.L.Bring: Design
Features and Zero Gravity Simulation of the GEOS Satellite Long Radial Boom Release.
ESTEC Publication Nr. 1511/71 AA by Dornier System GmbH, GiJnter K. Schmidt:
Cable Boom System for Spin-Stabilized Satellites - Design, Development, and Testing.
ESTEC Presentation at the 8 th Aerospace Mechanisms Symposium, October 1973 by G.L.
Bring: Development of and Dynamic Studies Concerning a Cable Boom System Prototype.
157
AA
B
C
D
E
F
G
H
I
K
Boom Cable with optical marks
Cable Drum
Flexlead
Central Hub
Housing
Worm Wheel
Worm
Motor
Motor Electronics
Optical Head and
processing Electronics
G
CBM Scheme
H
Fig. 1 GEOS - Cable Boom Mechanism
158 pOORQUALrrY
<3
Envelope
g
lectrical Leads Insulation
LoadWire
Index Marks
Signal Leads
Teflon Cable Body
Fig. 2 LRB Cable Cross Section
SCALE I 1 mm !
ORZGINAL PAGE _,
--- PTFE Body - '2 POOR QUALITY \ AWG 30 TF Hard\
0,5 0,35 . 0,85 \ 0,2
I
1
=. 14 mm 4
I
V
0.25
Fig. 3 :-Flexlead Cable Cross Section 159
E
i
S_ o_
17"6_.-I
OL
'PO
9"O
¢.0Iro
O'L
*f!
,.g
U
,,,eJ6OmON_eeD ,,UOM 9 "6!=1
Ott OOL 09
_u_u_
_p
wJo_, ;.o
._lno
! " low iN
¢.D
COUNTER
PHOTO TRANSISTOR
TIL 601/604
LIGHT SOURCE
GA-AS-DIODE
TIL 23/24
REFERENCE
PHOTO TRANSISTOR
TIL 601/604
/
/
OPTICAL HEAD:
Scheme
and
Hardware
.:+:.:.:
::::::::::
.......
-1
OPTICAL HEAD I
I
I
I
l
N-= i
I
I
I
I
l
Block Diagram of Processing Electronics
_ VIBRATION
__t suPPRESS.
Fig. 6 Deployment Length Indication
162
SQUARER


GEOS-20 m cable boom mechanism

The GEOS Cable Boom Mechanism which allows the controlled deployment of a 20 m long cable in a centrifugal force field is described. In launch configuration the flat cable is reeled on a 240 mm diameter drum. The electrical connection between the rotating drum and the stationary housing is accomplished via a flexlead positioned inside the drum. Active motion control of this drum is achieved by a self locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by an optical length indicator, sensing black bars engraved on the cable surface

Schmidt, G. K.

https://ntrs.nasa.gov/search.jsp?R=19780011097 2020-03-20T12:53:02+00:00Z
G EOS - 20 m Cable Boom Mechanism
By Giinter K. Schmidt and Klaus Suttner
Dornier System GmbH - Germany
ABSTRACT
The GEOS Cable Boom Mechanism allows the controlled deployment of a 20 m long cable in a
centrifugal force field. In launch configuration the flat cable is reeled on a 240 mm diameter drum.
The electrical connection between the rotating drum and the stationary housing is accomplished via
a Flexlead positioned inside the drum. Active motion control of this drum is achieved by a serf
locking worm gear, driven by a stepper motor. The deployment length of the cable is monitored by
an optical length indicator, sensing black bars engraved on the cable surface.
This paper describes the design, development, and testing of the operational modules.
Drum with Cable and Flexlead
Worm gear drive with stepper motor
and
Deployment length indicator
1. INTRODUCTION
GEOS is a ;rientific geostationary satellite spinning at 10 rpm in orbit. The payload consists of
seven experiments with approximately 30 modular units. Most of the experiment probes and
sensors had to be positioned at specific distances from the S/C surface to reduce body interference.
The location and orientation requirements of these probes led to the design of a Boom and
Mechanism Subsystem comprising of 8 different booms and 5 mechanisms. Two of the booms are
20 m long Cable Booms serving two active electronic sensors at their tips. During launch these
sensors are stowed tangentially on the spacecraft surface in experiment containers. When released,
these containers are opened to allow the sensors to swing out. The swinging motion is damped by a
release system and a tubular damper. This release system is called the "Experiment Release
Mechanism" and was presented by Mr. G. Bring from ESA at the May 76 Symposium in Frascati,
Italy. (Ref. 1). After the release motion is damped out, the two boom cables are radially deployed
by their "Cable Boom Mechanisms", whiuh are positioned inside the Spacecraft below the lower
equipment shelf.
2. BASIC DESIGN REQUIREMENT
Deployment length is 20 m.
Deployment accuracy is +__5 cm.
Intermittant synchronous deployment in 10 cm steps and general start-stop mode.
Test retractability and limited retractability in orbit.
All bearings are dry lubricated.
Maximum power consumption is 35 W.
Maximum height is 270 mm.
Magnetic cleanliness has to be achieved.
1 Dipole and 10 connection lines for signals and power between tip sensor and S/C.
Operation in vacuum between -20 and +55°C.
147
3. FUNCTIONAL DESIGN CHARACTERISTICS
A brief description of the Cable Boom Mechanism design is shown in Fig. 1. Additional details are
provided in a Design Study Report. (Ref. 2). The following will highlight the more interesting
functional groups: -
Cable and Flexlead
Worm gear drive
Stepper motor
Optical deployment sensor.
4. CABLE AND FLEXLEAD
For GEOS a flat cable of 1,5 x 7,3 mm cross section, consisting of five pairs of signal- and power
leads AWG 36 and one AWG 24 central load wire with 60 pf/m lead capacitance was used. (Fig. 2).
The cable was braided with twelve AWG 42 conductors and covered with gold plated Kapton tape.
One side was painted with 2 x 6 mm black bars spaced at 10 mm intervals for the optical length
indications. The cable was manufactured by HABIA, Sweden. Further details and dynamics of this
cable are provided in Ref. 3.
Major problems were created by use of the Kapton tape. Due to poor gold adhesion of the standard
tape, the gold had to be vapor deposited in an ultra high vaccuum chamber. Following this process,
a double sided self adhesive scotch tape was applied to the inner surface of the gold plated Kapton
tape. The tape was then wrapped around the braided cable body.
The Flexlead which is attached to the stationary housing is positioned within the cable drum. It is
reeled on the centre hub in the stowed configuration and unreeled onto the inner surface of the
worm wheel fixation ring in the deployed configuration.
The Flexlead cable which electrically connects the. rotating drum and the stationary housing, is a
flat teflon cable of 0,5 x 14 mm cross section witl', sixteen AWG 30 leads. The cable complied with
specified capacitance and impedance values. This cable was also developed and manufactured by
HABIA, Sweden.
To assure reliable performance, one side of the Flexlead cable is required to be as flat as possible to
reduce lateral forces between the layers during unreeling. The results of tests and post test analyses
led to a design shown in Fig. 3.
The geometrical lay-ou_ of the Flexlead is based on the following equations.
1wG
1. L=dm.W.Tr
2. dmi = d i + W i . S
dma = d a + W a . S
3. n = W i - W a
L = Flexlead length
W i = number of inner windings
W a = number of outer windings
n = number of revolutions
S = Flexlead cable thickness
d i = inner diameter
d a = outer diameter
148
,11
using the dimensionless Factors tilt. _'
the following Flexlead equation can be derived:
d==£ LT ,, ;t
a) Range of definition: d i _<d _< da
= ,, + - +
b) differentiated for maxima:
TLe Fiexlead Diagram, see Fig. 4, includes equations (a) and (b). For GEOS the following para-
meter_wereused: <j,= 6" _' == _.jp _,_ = q_'_
A Flexlead cable length of 12 m for 37 reel revolutions was derived from this diagram. A coiling
factor of 0,9 was used.
The Flexlead was built and tested according to these parameters and performed successfully.
5. WORM GEAR DRIVE
For a cable boom system, a worm gear drive has fundamental advantages. Since cable booms deploy
by the action of centrifugal force induced by the spinning satellite, deployment forces need not be
provided. The task of the gear in this case is to prevent uncontrolled deployment. This can be
obtained in a very efficient way with a self locking worm gear. The lower the self locking efficiency,
the lower the torque requirement at the worm shaft necessary to control deployment motion. Thus,
deployment control can be accomplished with a very small motor.
However, these operational conditions with the use of dry lubrication require a very careful design
of the worm gear configuration and material selection. Of considerable importance are stable
friction conditions between worm and worm wheel.
Several material combinations were tested in a special test to determine their frictional behaviour as
a function of operation time. Excellent results were obtained with a titanium worm and a
HOSTAFLON worm wheel. In actuality, the initial friction of this combination is rather high.
However, the friction reduces after a run-in period to a very constant value. A friction value of
about _u= 0,16 to 0,18 was determined as the result of these friction investigations. Considering this
value and the configuration data the gear data was thereby chosen:
pitch 2 mm
gear ratio 100
pitch angle 6,33 °
With this gear design and the available torque of the stepper motor, an operational range of # = 0,11
to 0,25 was achieved, providing a sufficient safety margin. The design parameters for the worm gear
can be obtained from the worm gear Nomogram (Fig. 5) which was specifically developed for this
drive assembly.
Full conformity between design and actual hardware was demonstrated during qualification testing.
149
6. THE MOTOR
A size 11, 4 phase variable reluctance stepper motor was chosen to drive the Cable Boom
Mechanism.
Even consinering the poor efficiency of these motors, they provide sew'ral important advantages:
Small rotational speed without gear head and speed variation capability
High calculated reliability due to minimal amount of mechanical parts
Low residual magnetism following switch off
Digital servo electronics
Simple electronic synchronisation of several motors.
The motors, used for the GEOS Cable Boom Mechanisms, were specially developed by SAGEM,
France. These stepper motors can provide a starting torque of more than 25 Nmm. The length of
the housing is 52 mm and its mass 125 g. The motor has a step angle of 15 ° and runswith 12 Hz
(speed A) and 48 Hz (speed B).
The motor is operated by a Motor Control Electronic (MCE), which functions in several deploy-
ment modes, with a synchronous four phase driver signal for two stepper motors.
I
i
I
7. DEPLOYMENT LENGTH INDICATOR
The purpose of the deployment length ind;cator is to measure the deployed length of the boom
cable. It consists of the following:
the optical head and
the processing electronics.
The optical elements of the optical head consist of a matched pair of light emitting diode and photo
transistor. The geometrical arrangement of both of these devices assure that the maximum possible
amount of emitted light is reflected into the photo transistor. Reflectance is achieved by a gold
plated cover tape on the Boom Cable, which passes under the optical head. Maximum reflection
occurs when the optical axes of the light emitting diode and the photo transistor intersect in the
plane of the cover tapes. The gold plated cover tape is marked with a periodic pattern of non-
-reflecting black bars, that are spaced 10 mm apart and are 2 mm wide. (Fig. i
The processing electronics generate a counting pulse when a bar has passed the optical head in either
direction. However, no counting will occur if the bars are oscillating back and forth in the cable axis
direction at amplitudes of less than 5 mm. To achieve this count deletion, a second optical element
in the optical head is displaced from the first by 5 mm in the cable axis direction. Using the outputs
of both optical elements, the counting pulses due to cable longitudinal oscillations are automatically
suppressed by the processing electronics. For reliability purposes, the arrangement of the two
optical elements is duplicated !n the optical head, the cutputs of the redundant photo transistors
being OR-9ated.
150
8. TESTING
The Cable Boom Mechanism as a unit was successfully tested at development, qualification and
accepta.lce levels. The following environmental tests were carried out at unit level:
Vibration tests - sinus and random
Thermal - Vacuum test between -30 ° and +60°C at a pressure less than 10 .7 Torr
Electromagnetic Cleanliness Tests
The environmental tests were accompanied by unit performance tests. The most significant and
comprehensive performance test was accomplished by means of a special Unit Test Rig.
This Unit Test Rig consists of an electronic Unittester simulating the electrical interfaces to the
Satellite, and a test fixture simulating the mechanical orbit conditions. It also allows the simulation
of any required orbital deployment load characteristic.
The deploying cable is stored on a drum which simulates the cable load by means of a controllable
torque motor. The torque profile is provided and monitored via the Unittester. The Cable Boom
Mechanism itself is mounted on a base plate supported by bar springs. Strain gauges positioned at
the bar springs measure the cable loads, applied to the drum.
The test fixture is very compact and enables simulated Cable boom deployments also in small test
chambers. In addition te these unit tests, comprehensive component tests were carried out with the
Boom cable, and cable marks, Flexlead cable, stepper motor, worm gear, optical head and control
electronics.
i
i
9. CONCLUSIONS
For the GEOS satellite a 20 m Cable Boom Mechanism was designed, developed and qualified. This
effort was sponsored by the EUROPEAN SPACE AGENCY as part of the GEOS Development
Contract.
The layout of the Flexlead and tPe worm gear required rather careful consideration. Problems
associated with the adhesion of the gold layer and the black marks on the gold surface as v, ell as
with the optical h']d had to be solved.
However, due to the modular configuration and the availability of a parametric design lay-out and
computer programs, the application of this mechanism is not limited to a 20 m cable, but can be
easily adapted to other configurational requirements and applications. Longer and heavier cables
can be deployed and retracted with a stronger motor for instance.
The application range of this mechanism covers 100 and more metres deployment lenght. If neces-
sary, a deployment accuracy of less than 1 cm can be achieved.
10.
1)
2)
3)
REFERENCES
ESA SP 117, Presentation held in Frascati, Italy 24-26 May 1_7R by G.L.Bring: Design
Features and Zero Gravity Simulation of the GEOS Satellite Long Radial Room Release.
ESTEC Publication Nr. 1511/71 AA by Dornier System GmbH, Gunter K. Schmidt:
Cable Boom System for Spin-Stabilized Satellites - Design, Development, and Testing.
ESTEC Presentation at the 8 th Aerospace Mechanisms Symposium, October 1973 by G.L.
Bring: Development of and Dynamic Studies Concerning a Cable Boom System Prototype.
151
AB
C
D
E
F
G
H
I
K
A
Boom Cable with optical marks
Cable Drum
Flexlead
Central Hub
Housing
Worm Wheel
Worm B
Motor
Motor Electronics
Optical Head and
processing Electronics
l,
CBM Scheme
G
a B F D H G
t" E
Fig. 1 GEOS - Cable Boom Mechanism
15,)
L.. 7,3mm
I ..... '-- - 2,0 _'= < 3
,ii---I,0- _i_l,l
IIIIII
• l
15
-- Teflon Cable Body
Fiq. 2 LRB Cable Cross Section
SCALE t 1 mm I
1 PTFE Body _ AWG 30 TF Hard\
0,5 0,35 0,85 \ 0,2
"',, _ 0,5mm !
............ 14 mm ....................... _
Fig. 3 Flexlead Cable Cross Sect=on 133
DOFiI_IEFI
|
o
o
E
a
_L_
x
LJ.
•-Ib _. _ o.. Od
134
IE
01
o
E
o
Z
o
IJ.
133
REPROI)UCIBIIYI'Y OP 'rile
,),_.I(;INAi. _,;\,_iI; IS POOR
COUNTER
PHOTO TRANSISTOR
TIL 601/604
LIGHT SOURCE
J -f_T_ _ GA-AS-DIODE
/ ..... i L _" TIL 23/24
REFERENCE
PHOTO TRANSISTOR
TIL 6011604
OPTICAL HEAD:
Scheme
and
Hardware
L-
3
OPTICAL HEAD I
I
Fig. 6
Block Diagram of Processing Electronics
Deployment Len_jth Indication
I56
SQUARER J .....
VIBRATION[SUPPRESS. ---_
° •



GEOS-20 m cable boom mechanism

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server

NASA Technical Reports Server