Automatic Control in Aerospace 1989. Selected Papers from the IFAC Symposium, Tsukuba, Japan, 17–21 July 1989

284 Pages·1990·36.41 MB·English

by  T. Nishimura

IFAC SYMPOSIA SERIES
Editor-in-Chief
JANOS GERTLER, Department of Electrical Engineering,
George Mason University, Fairfax, Virginia 22030, USA
JOHNSON et al.\ Adaptive Systems in Control and Signal Processing {1990, No. 1)
ISIDORI: Nonlinear Control Systems Design {1990, No. 2)
AMOUROUX & EL JAI: Control of Distributed Parameter Systems {1990, No. 3)
CHRISTODOULAKIS: Dynamic Modelling and Control of National Economies {1990, No. 4)
HUSSON: Advanced Information Processing in Automatic Control {1990, No. 5)
NISHIMURA: Automatic Control in Aerospace {1990, No. 6)
RIJNSDORP et al: Dynamics and Control of Chemical Reactors, Distillation Columns and Batch Processes
(DYCORD '89) {1990, No. 7)
UHI AHN: Power Systems and Power Plant Control {1990, No. 8)
REINISCH & THOMA: Large Scale Systems: Theory and Applications {1990, No. 9)
KOPPEL: Automation in Mining, Mineral and Metal Processing {1990, No. 10)
BAOSHENG HU: Analysis, Design and Evaluation of Man-Machine Systems {1990, No. 11)
PERRIN: Control, Computers, Communications in Transportation {1990, No. 12)
PUENTE 8c NEMES: Information Control Problems in Manufacturing Technology {1990, No. 13)
NISHIKAWA & KAYA: Energy Systems, Management and Economics {1990, No. 14)
DE CARLI: Low Cost Automation: Components, Instruments, Techniques and Applications {1990, No. 15)
KOPACEK, MORITZ & CENSER: Skill Based Automated Production {1990, No. 16)
COBELLI 8c MARIANI: Modelling and Control in Biomedical Systems {1989, No. 1)
MACLEOD 8c HEHER: Software for Computer Control (SOCOCO '88) {1989, No. 2)
RANTA: Analysis, Design and Evaluation of Man-Machine Systems {1989, No. 3)
MLADENOV: Distributed Intelligence Systems: Methods and Applications {1989, No. 4)
LINKENS 8c ATHERTON: Trends in Control and Measurement Education {1989, No. 5)
KUMMEL: Adaptive Control of Chemical Processes {1989, No. 6)
CHEN ZHEN-YU: Computer Aided Design in Control Systems {1989, No. 7)
CHEN HAN-FU: Identification and System Parameter Estimation {1989, No. 8)
CALVAER: Power Systems, Modelling and Control Applications {1989, No. 9)
REMBOLD: Robot Control (SYROCO '88) {1989, No. 10)
JELLALI: Systems Analysis Applied to Management of Water Resources {1989, No. 11)
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A U T O M A T IC C O N T R OL IN A E R O S P A CE
Selected papers from the IFAC Symposium,
Tsukuba, Japan, 17-21 July 1989
Edited by
T. NISHIMURA
Institute of Space and Astronautical Science,
Sagamihara, Japan
Published for the
INTERNATIONAL FEDERATION OF AUTOMATIC CONTROL
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First edition 1990
Library of Congress Cataloging in Publication Data
Automatic control in aerospace: selected papers from the IFAC
symposium, Tsukuba, Japan, 17-21 July 1989/edited by T. Nishimura.
—1st ed.
p. cm.—(IFAC symposia series: 1990, no. 6)
I. Airplanes—Control system—Congresses. 2. Space vehicles—
Control systems—Congresses. I. Nishimura, T. (Toshimitsu), 1930-
II. International Federation of Automatic Control. III. Series.
TL678.A93 1990 629.132'6—dc20 90-31776
British Library Cataloguing in Publication Data
Automatic control in aerospace
I. Space vehicles. Automatic control
I. Nishimura, T. II. International Federation of
Automatic Control III. Series
629.4742
ISBN 0-08-037027-6
These proceedings were reproduced by means of the photo-offset process using the manuscripts supplied by the
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lay-out, figures and tables of some papers did not agree completely with the standard requirements: consequently
the reproduction does not display complete uniformity. To ensure rapid publication this discrepancy could not be
changed: nor could the English be checked completely. Therefore, the readers are asked to excuse any deficiencies
of this publication which may be due to the above mentioned reasons.
The Editor
Printed in Great Britain by BPCC Wheatons Ltd, Exeter
IFAC SYMPOSIUM ON A U T O M A T IC CONTROL
IN AEROSPACE
sponsored by
Technical Committee on Aerospace (IFAC)
Co-sponsored by
The Japan Society for Aeronautical and Space Sciences Liaison Committee
with IFAC TC Aerospace
Society of Instrument and Control Engineers of Japan Technical Committee
on Guidance and Control in Aerospace
Institute of Electronics, Information and Communication Engineers
Technical Group on Space, Aeronautical and Navigational Electronics
Organized by
Japanese IFAC Aerospace Symposium Organizing Committee
International Programme Committee
D. B. DeBra, USA (Chairman) A. H. Reynaud, Canada
G. Bertoni, Italy J.J. Rodden, USA
E. Gottzein, FRG A. J. Sarnecki, UK
S. C. Gupta, India D. N. Soo
W. Haeussermann, USA T. Tanabe, Japan
M. Higashiguchi, Japan H. Tolle, FRG
J. W. Hursh, USA I. N. Vasiljev, USSR
Yangjia-Chi, PRC P. Y. Willems, Belgium
P. Kant, The Netherlands W. Wimmer
K. R. Lorell, USA H.-D. Zago
M.J. Pelegrin, France
National Organizing Committee
T. Tanabe (Chairman) T. Nakao
K. Fukuizumi K. Ninomiya
M. Higashiguchi T. Nishimura
H.Ihara M. Ghara
M.Ikeuchi Y. Ohkami
M. Kamata S. Sakano
K. Kanai R. Seo
Y. Kosaka M. Shigehara
H. Koshiishi J. Tabata
T. Kumazawa Y. Takizawa
H. Kurokawa M. Torii
M. Kusanagi N. Yajima
K. Machida H. Yamamoto
S. Manabe T. Yasaka
N. Nagao
Advisers
T. Godai
H. Maeda
H. Nagasu
T. Nomura
Copyright © IFAC Automatic Control in PLENARY SESSION
Aerospace, Tsukuba, Japan, 1989
NASDA'S LONG-RANGE PLAN AND
AUTOMATIC CONTROL
M. Nagatomo
Program Planning and Management Department,
National Space Development Agency of Japan (Ν AS DA), Tokyo, Japan
Abstract. A long-range plan of NASDA's space development, until the
beginning of the 21st century and thereafter, is outlined, and automatic
control-related features and technologies of the space systems appearing
in this long-range plan are described. Currently, NASDA is developing
world-level rockets and satellites such as the H-II rocket and the
Engineering Test Satellite-VI (ETS-VI). And, NASDA is about to develop
the Japanese Experiment Module (JEM) participating in the International
Space Station (ISS) program. In the future, NASDA intends to place
emphasis on the development of the space infrastructure including such
future space systems as the H-II Orbiting Plane (HOPE), the H-II derived
rockets, the Rocket Plane (RP), space-to-space transportation systems,
the Data Relay and Tracking Satellite (DRTS), manned space facilities,
various platforms, etc. And, the space infrastructure around the earth
will be extended to the moon and planets. The space infrastructure will
be developed economically by employing unmanned systems as much as
possible, safely by employing fully-automatic, manned systems, and
efficiently by promoting international cooperation with autonomy.
keywords. Actuators; Attitude control; Guidance systems; Manipulation;
Navigation; Robots; Satellites, artificial; Sensors; Space vehicles;
Strapdown systems.
1. INTRODUCTION (l)From now until the first half of the
1990s, the establishment of original and
NASDA has been conducting space fundamental technologies for large-scale
development in various fields over the rockets and satellites, which Japan should
past 19 years. NASDA had developed the own, are to be pursued through the
N-I, N-II, and H-I rockets, and has been development of the H-II rocket and the
developing the H-II rocket capable of ETS-VI. The development of space
launching a two-ton class geostationary Infrastructure, Including the JEM, which
satellite and equipped with cryogenic is a foundation for space activities, will
(L0X/LH2) engines. And, NASDA has been be pursued.
developing communications, broadcasting,
meteorological observations, earth (2)From the last half of the 1990s to the
observations, and engineering test beginning of the 21st century, the
satellites Including the Engineering Test operation of the JEM, and the development
Satellite-VI (ETS-VI) weighing about two and operation of space Infrastructure
tons in a geostationary orbit and equiped around the manned space station of the ISS
with an Ion engine system for nortii-south program will be advanced. This will
orbit control. Through the development of promote manned space activities and
the H-II rocket and the ETS-VI, NASDA Is encourage the space Industry to become
well on Its way to acquire world-level self-supporting. The exploration of the
technologies of lauch vehicles and moon and planets will be also started.
satellites. In addition to the activities
mentioned above, NASDA has been conducting Under these basic directions, a long-range
the First Material Processing Test (FMPT) plan on the development of space
program utilizing the Space Shuttle, and infrastructure and the evolution of manned
is about to start the development of the space activities, extended until the
Japanese Experiment Module (JEM) attached beginning of the 21st century, has been
to the manned space station of the investigated as follows:
International Space Station (ISS) program.
From now until the first half of the
Based on the space development conducted 1990s, the development of the JEM will be
so far, NASDA will pursue Its space advanced. At the same time, the
development in line with the following utilization of the Space Flyer Unit (SFU)
directions, solely for peaceful purposes, for microgravity experiments, the
aiming at acquiring the capability to acquirement of manned support technologies
promote autonomous space activities by through the FMPT program, the preparation
developing world-level, domestic of training facilities required for manned
technologies and extending positively space systems, and the preparation of the
International cooperation suitable to support systems to promote the utilization
Japan's role in international society: of microgravity environment in space will
be accomplished. Furthermore, the research
1
Μ. Nagatomo
and development of inter-satellite entirely with domestic technologies to
communications will be promoted for the contribute to world space activities. The
operation of the JEM, etc. Besides, the H-II rocket and the H-II derived rockets
development of the H-II rocket equipped under study will be used not only to
with a strapped-down inertial guidance launch satellites but also to support the
system utilizing laser-gyros will be operation of space infrastructure.
advanced. And, the research and
development of an unmanned, winged (1) H-I Rocket
recovery vehicle launched by the H-II
rocket (HOPE), capable of performing The H-I rocket is a current Japan's main
rendezvous-docking and automatic landing« launch vehicle. Four launches of the
will be promoted. Furthermore, the rocket have been successfully made to
precursor research and development of a launch a geodetic satellite, an
rocket plane, a fully-resusable, winged engineering test satellite and two
rocket, and a space plane will be also communications satellites since the first
promoted. one was successfully made in August 1986.
In the latter half of the 1990s, the The H-I rocket is a two or three-stage
operation of the JEM/ISS will be rocket capable of launching an about 550
commenced. The development of an orbital kg satellite into a geostationary orbit.
maneuvering vehicle equipped with robot It is about 40 meters in total length and
arms, the development and operation of a 2.5 meters in outside diameter. Its
co-orbiting platform enabling long lift-off weight is about 140 tons. The
duration experiments under better first stage, strap on boosters and
microgravity environment, and the payloard fairing are the same as those of
development of a Japan's own polar the former N-II rocket. However, the
orbiting platform forming a community of second stage, the third stage and the
international polar orbiting platforms inertial guidance system were newly
will be implemented. And, materials will developed using Japanese own technologies.
be trnsported using the H-II rocket, the The second stage is equipped with a
HOPE, and H-II derived rockets. The high-performance liquid-oxygen and
research and development of a rocket plane liquid-hydrogen engine, called the LE-5
and/or a space plane will be promoted. engine, with a restart capability. The
Furthermore, an space operation and data third stage is equipped with a solid
system employing data relay satellites for rocket motor.
inter-satellite communications, a landing
facility from space, etc. will be
completed.
w
In the beginning of the 21st century, the
utilization of the JEM/ISS will be
extended, a manned platform will be
developed and operated, and the
development of a rocket plane and/or a
space plane will be promoted for operation 1. ?ArL0*3 fAiHiNC : »*^LOAO ATAC FiTTlKC 3 Tt<(fl:$7*c£s:iiow2:o«
in the primary stage. Furthermore, the I£. «CCUA.O*ATN{RC fS £SC£TCl:3iOr.'K S SiCOMC STACt tHQ'Hi
Geostationary Platform (GPF) and an
orbital transfer vehicle to trnsport the 13 $Ti4» OK lOCSTt* U SCIRT SECTIW 15 £7AGt MAIM l»<Cl>is
GPF from a low earth orbit to a Fig. 2.1. Congiguration of the H-I rocket
geostationary orbit will be developed.
The inertial guidance system called NICE
The evolution of space activities after is installed at the top of the second
the beginning of the 21st century has been stage. It is a stable platform type
investigated as follows: inertial guidance system and consists of
Inertial Measurement Unit (IMU) and
Japan's own space station forming a Inertial Guidance Computer (IGC). IMU
community of international space stations consists of Inertial Platform Unit (IPU)
will be constructed and operated. And, a and Platform Electronics Unit (PEU). IPU
large-scale space factories utilizing the houses three rate-integrating gyros and
space station as a base will be three accelerometers mounted on a
constructed and operated, while a low-cost 4-gimbal-axis platform. Rate gyros are
transportation system will be al^o installed both in the first and second
completed and placed in service. stages. The principal functions of NICE
Furthermore, exploration activities in are navigation, guidance adopting an
space will be extended to ones such as the explicit steering law, attitude control,
routine observation of space from an flight sequence control, tank pressure
in-orbit astronomical observatory, the control, etc. Attitude control moments are
direct exploration of celestial bodies in obtained by the gimbal actuation systems
the solar system, and sample returns. of the main and vernier engines for the
first stage, and by the gimbal actuation
systems of the main engine and the
2. SPACE TRANSPORTATION reaction control systems for the second
SYSTEM stage.
NASDA has been developing the expendable The H-I rocket will be used as a main
satellite launch vehicles of the N-I, launch vehicle of Japan until the
N-II. H-I and H-II rockets. The N-I and beginning of the 1990s. Five more launches
N-II rockets were already phased out, the of the H-I rocket are scheduled to be made
H-I rocket is now under operation, and the from 1989 through 1992 to launch a
H-II rocket is now under development. The geostationary meteorological satellite,
main parts of the H-I rocket were two earth observation satellites and two
developed domestically to meet Japan's broadcasting satellites of Japan.
satellite launch demands. On the other
hand, the H-II rocket is to be developed
NASDA's Long-range Plan and Automatic Control
pre-launch inspection and monitor.
Guidance accuracy is estimated to be 250
km (3-sigma) in apogee altitude and 0.03
C»*«TC« ^ deg (3-sigma) in inclination angle of a
II geostationary transfer orbit.
i««swcf«tn
U-JT .IHIjJ
Payload fairing
Payload
attachment fitting
Guidance section
2nd-stage LH tank
2nd-stage LOX tank
Inter-stage
2nd-stage engine
'(LE-5A)
lst-stage LOX tank
Center body
seclion
Fig. 2.2. Guidance and control system of
the H-I rocket ist-stage LH tank
(2) H-II Rocket
A Japan's main launch vehicle In the 1990s
will be the H-II rocket, a successor of
the H-I rocket. The H-II rocket is under
development aiming at the first test
flight in 1992. It is to be developed 1st-stage
entirely with Japanese technologies based engine section Auxiliary engine
on the experiences obtained through the
development of the H-I rocket.
lst-stage main enaine
Solid rocket (LE-7)
The H-II rocket is a two-stage launch booster
vehicle capable of launching a
geostationary satellite weighing about 2.2
Fig. 2.3. Configuration of the H-II rocket
tons. It Is also capable of launching
multiple payloads, totaling 2 tons,
Μ * in STACC
simultaneously into a geostationary orbit.
Liquid-oxygen and liquid-hydrogen engines
^v. L ~¥ «···. ^·ττπ.;
are adopted both for the first stage and
I -γ- ^
for the second stage, and two large solid
boosters are attached to the first stage.
The H-II rocket is A meters in diameter
and 49 meters in height. Each solid
booster is 1.8 meters in diameter and 23
meters in height. The H-II rocket weighs
about 260 tons at lift off.
A new liquid oxygen and liquid-hydrogen
engine, called the LE-7 engine, is under
development for the first stage. The LE-7
engine is a high performance engine
adopting a high-pressure staged-combustion
cycle, and can make a thrust of about 93
tons at sea level. The improved version of
the LE-5 engine, called the LE-5A engine,
is under development for the second stage.
Each solid booster makes a thrust of 160 Fig. 2.4. Guidance and control syste of
tons at sea level and is equipped with a the H-II rocket
movable nozzle for thrust vector control.
The system is installed on the top of the
A strapped-down inertial guidance system second stage and consists of Inertial
was selected for the guidance and control Measurement Unit (IMU), Inertial Guidance
system of the H-II rocket, because of its Computer (IGC), Inertail Guidance Program
superior mission flexibility and high (IGP). Data Interface Unit (DIU). Control
reliability. The functions of the system Electronics Packages (E-PKGs) and Lateral
are initial alignment, navigation, Acceleration Measurement Unit (LAMU). IMU
guidance, attitude control, sequence contains three ring laser gyros (RLGs) and
control, propulsion system control, three accelerometers. RLG has many
Μ. Nagatomo
advantages such as wide range of input capability, reliability, launch cost,
rate, high reliability, no etc., it will contribute to world
acceleration-sensitive drift, etc. over a satellite launch demands. The H-II rocket
conventional gyro. LAMU contains two will be used not only for satellite
accelerometers on pitch and yaw axes, launches but also for materials supply to
whose data are used for load relief the International Space Station.
control at the maximum point of dynamic
pressure. The IMU's and LAMU's data are (3) H-II Derived Rockets
sent to IGC/IGP at a rate of 32 samples
per second, and IGC/IGP makes a As the construction and operation of such
computation of navigation and guidance at space facilities as the International
a rate of 1 Hz and that of attitude Space Station will start, space
control at a rate of 32 Hz. transportation demands will increase in
the latter half of the 1990s and
NASDA plans to launch a total of three thereafter. To cope with this situation,
TR-I test rockets which obtain the NASDA is studying the performance
necessary technical data, and also confirm improvement of the H-II rocket. The
the functions of the subsystems for the easiest option to increase the launch
H-II design. The first two TR-Is flew in capability of the H-II rocket is to add
summer 1988 and winter 1989. The third, two or four more solid boosters. The
last TR-I is scheduled to be launched in option having six solid boosters can lift
this summer. There are two main objectives about 15 tons into a 300 km orbit, as
of the TR-I mission. The first objective compared to the H-II rocket which lifts
is to obtain flight data, such as about 10 tons into the same orbit.
aerodynamic pressure , heat, sound and
vibration generated by the atmospheric More significant improvement can be
effects on the vehicle through flight. The obtained by attaching two large
second objective is to confirm the liquid-fuelled boosters with two solid
function of the Solid Rocket Booster (SRB) boosters. The option having two liquid
separation mechanism. The TR-I is a oxygen and hydrogen boosters each with the
single-stage rocket, one-quarter the size LE-7 engine, which is almost equivalent to
of the H-II rocket. It is 14.3 meters in the option strapping three H-II first
overall length, 1.1 meters in diameter, stages together, can lift about 24 tons
and weighs about 11.8 tons. into a 300 km orbit. Even higher
performance and lower operation cost will
Adapter come from adopting a liquid oxygen and
Section hydrocarbon booster. The option having two
liquid oxygen and hydrocarbon boosters can
lift about 34 tons into a 300 km orbit.
SRB Front
Separation
Sect ion Nose A more advanced option adopting the
airbreathing engine such as the Liquid Air
Fairing
On-board Cycle Engine (LACE) is also studied. An
Equipment airbreathing engine has an advantage that
Section it can reduce the amount of a liquid
On-board oxygen consumption, because it uses air as
Equipment an oxidizer during the early phase of its
Recovery Section flight.
Equipment^
3. SPACE UTILIZATION SYSTEM
Separation
Plane
Solid Fueled Space utilization systems are divided into
Rocket Motor space position utilization systems and
SRB Rear space environment utilization systems.
Separation Dummy SRB Space position utilization systems are the
Section space utilization systems which utilize
such positions of space as geostationary
Tail Fin orbits and polar orbits for
communications, broadcasting,
Solid Motor meteorological observation and earth
Roll Control observation. On the other hand, space
Unit (SMRC) environment utilization systems are the
space utilization systems which utilize
the microgravity environment of space for
material processing and life science
experiments.
Fig. 2.5. Configuration of the TR-I rocket 3.1. Engineering Test Satellites
A new launch site for the H-II rocket is Engineering test satellites have been
under construction in the Tanegashima developed aiming at the establishment of
Space Center located in the southern the basic technologies of satellites to
island of Japan. The H-II rocket will be apply those to future practical
used as a main rocket of Japan from the satellites. The last engineering test
beginning of the 1990s to launch various satellite was Engineering Test Satellite-V
payloads. In the first half of the 1990s, (ETS-V) weighing about 550 kg which was
an engineering test satellite, a successfully launched into a geostationary
microgravity experiment satellite, a orbit using the three-stage H-I test
geostationary meteorological satellite and rocket in August 1987. It established the
an earth observation satellite of Japan basic technologies needed for
are scheduled to be launched using the geostationary three-axis stabilized
H-II rocket. Since the H-II rocket is at satellite bus systems and has been
high level in such points as launch successfully carrying out mobile satellite
NASDA's Long-range Plan and Automatic Control
comeunications experiment with aircrafts, has many remarkable features as follows:
ships and automobiles taking the The ETS-VI is a box-type satellite with
initiative in the world. the design lifetime of 10 years for
satellite bus and the end-of-life power of
(1) ETS-VI. The Engineering Test 4,100 W at summer solstice. A truss type
Satellite-VI (ETS-VI), a three-axis tower to hold three antennas extends about
stabilized geostationary satellite 5 meters from the earth-facing panel. Two
weighing about 2 tons is under development solar arrays extend about 15 meters each
and scheduled to be launched in 1992 using from the south-facing and north-facing
the H-II rocket. The main objectives of panels. Each solar array wing has four
the ETS-VI project are to establish the hinged light-weight semi-rigid panels with
satellite bus system which meets the 50 micron meters thick silicon solar
requirements in the field of satellite cells. The payload mass including the
communications and broadcasting in the tower is more than 660 kg. Other major
1990s, and to demonstrate advanced design features are use of a restartable
technologies on advanced fixed satellite bipropellant 2,000 Ν engine for apogee
communications, mobile satellite maneuvers. 25 mN Xenon-fueled ion engines
communications, and inter-satellite for north-south station-keeping,
communications needed in the 1990s. The large-scale, light-weight body structure,
and many Hybrid IC's and LSI's for
technologies on inter-satellite
reducing components weight.
communications will be used for the
development of the Data Relay and Tracking
Satellite (DRTS) which is a key subsystem The attitude control system (ACS) of the
of the Space Operarion and Data System ETS-VI is a microprocessor based zero
(SODS) . momentum three-axis control system using
four skew-mounted reaction wheels. The ACS
has many remarkaible features as follows:
TTC Anc«nn«
Sol*r Ψ·4ΑΙ·
Hi eiab«l«d ikr.t«MM <or -High accuracy attitude control
Sin$:« Acne* CeMMAic«ti*ni
Attitude control errors are less than 0.05
degrees for roll and pitch axes, and less
than 0.15 degrees for yaw axis in
S'hiii riMMj Arrey AAMIMA for geostationary orbit. To achieve the
Xr.t*r-Mt«i:iM CsMKnicaCion* accuracy, precise earth sensors (ESA) are
lSAtrXufc«t-; ae«l* ii9nt--*i5fti tody used mainly for roll and pitch axes
control, and a strap down control system
•Λ1Λ Silisso with the Inertial Reference Unit (IRU) is
se:«r c«::« employed for yaw axis control.
-Tree axis control in transfer orbit
A three-axis stabilized attitude control
system is employed in transfer orbit, too.
The Fine Sun Sensor.(FSS) and the IRU are
used for yaw axis control, the FSS and the
Rate Integral Gyro (RIGA) are used for
pitch axis control, and the IRU is used
for rol axis control. The ESA is used for
the IRU calibration at specific period in
transfer orbit.
-Autonomous functions
The ACS adopted many autonomous functions,
Fig. 3.1.1. Configuration of the ETS-VI some are to eliminate ground operations,
others are to increase survivability. The
formers are initial acquisition sequences
from separation to sun acquisition in
:<-b*r.d/C-b*.-ici transfer orbit, auto unloading, auto gyro
calibration and auto sun biasing. The
latters are fault tolerant functions by
duplex CPU operation, auto switching to
redundant components in case of failure
and auto sun acquisition in case of loss
of earth.
-Re-programing capability
The ACS flight software can be
re-programmed on orbit from ground command
to change the control parameters or
software program if required and it is
also used for experimental purpose to
evaluate the advanced control
technologies.
The K-band Single Access (KSA) antenna
system is mounted on the earth-facing
panel of the main body to demonstrate the
advanced technology of inter-satellite
communications. The KSA antenna system has
the Antenna Pointing Mechanism (APM) to
acquire and track low earth orbit
satellites such as the Advanced Earth
Observing Satallite (ADEOS) and ground
stations. The APM employs a 2-axis-gimbal
system consisting of a stepping motor, a
harmonic drive and a position indicator.
Fig. 3.1.2. Exploded view of the ETS-VI
M. Nagatomo
demands and develop advanced satellite
Ε» 3f we communications technologies. The third
generation Communications Satellites
(CS-3S), consisting of CS-3a and CS-3b,
were launched in 1988 using the H-I
ACE rocket. The CS-3 is a spin-stabilized
RIM satellite weighing about 550kg and
consisting of a despun section that is
always directed towards the earth and a
90-rpm rotating spin section. The despun
section holds a communications antenna
while spin section contains transponders,
bus equipments, etc. The CS-3
VCE communications subsystem contains ten
channels at Ka band and two channels at C
-ροε band.
-RIU
Fig. 3.1.3. Attitude Control System (ACS)
of the ETS-VI
Fig. 3.1.4. Configuration of the Antenna
Pointing Mechanism (APM)
Fig. 3.2.1. Configuration of the CS-3
An experiment on modal parameter
identification, and attitude and vibration
The design life time of CS-3 is seven
control is planned to be performed as one
years, therefore, the fourth genaration
of the flight experiments of the ETS-VI
Communications Satellites (CS-4s) will be
having flexible appendages of two long
necessary in 1995 for the continuation of
solar paddles. Three accelerometers are
the satallite communications service by
mounted on each paddle to measure the
the CS-3. As for the CS-4, a 2-ton class
in-plane and out-of-plane bending modes.
satelite using the ETS-VI bus is
As for the modal parameter identification,
considered to be necessary for increasing
the spacecraft is excited by the thrusters
and diversifying communications demands.
of the RCS to cause the paddle vibration,
and measured acceleration of the paddle
3.3 Broadcasting Satellites
vibration is used for off-line modal
analysis. As for the attitude and
vibration control, controller parameters The direct broadcasting satellite series
are tuned to be optimal values based on have been developed to meet increasing
the identified modal parameters, and an broadcasting service demands and develop
experiment of closed-loop attitude and advanced satellite broadcasting
vibration control is performed. technologies. At present, the BS-2b, one
of the second generation direct
Broadcasting Satellites (BS-2s), is
providing satellite broadcasting service.
And, the third generation direct
Broadcasting Satellites (BS-3s),
consisting of BS-3a and BS-3b, are now
being developed by NASDA, and scheduled to
be launched in 1990 and 1991,
respectively, using the H-I rockets. The
design life time of the BS-3 is seven
years, therefore, the fourth genaration
direct Broadcasting Satellites (BS-4s)
will be necessary in 1997 and 1998 for the
continuation of the satallite broadcasting
service by the BS-3. As for the BS-4, a
PITCH few concepts including a 2-ton class
satelite using the ETS-VI bus are studied
to meet increasing and diversifying
Fig. 3.1.5. Accelerometer locations for
broadcasting demands.
the attitude and vibration
control experiments
(1) BS-3. The BS-3 is a box-type and a
The Communications Satellite series have three-axis stabilized satellite weighing
been developed to meet increasing and about 550 kg. The BS-3 carries three
transponders with the output power of 120
diversifying domestic communications
w or more in order to make three channels
of color television broadcasting. The BS-3