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A low cost multimission bus for small satellites applications
Acta Astronourica, Vol. 39. No. 9-12. pp. 987-992. 1996 91997 Published by Elscvier Science Ltd Printed in Great Britain p11:soo94-5765(97)000854 0149-1970/96 $17.00+0.00
A LOW COST MULTIMISSION BUS FOR SMALL SATELLITES APPLICATIONS Philippe BERTHEUX, Francis DOUILLET, Jean Claude CHIARINI AEROSPATIALE CANNES 100 Bd du Midi, Cannes La Bocca, BP-99 06322 Cedex ABSTRACT - This article presents the AEROSPATIALE ESPACE & DEFENSE industrial approach for the CNES PROTEUS platform. Three major targets were assigned to the PROTEUS plat$onn. A very wide field of missions (orbits, attitude, instruments and launch vehicle compatibility) will be implemented on PROTEUS platform at a very attractive cost and within a 24 months delivery time. A cost driven system methodology has been established to produce a recurring platform at a very attractive cost. Cost reductions choices were analysed and selected on organisation, engineering, procurement, quality and industrialisation. 01997
1.
Published
by Elsevier
Science
Ltd.
the platform Technically, architectures are generic. Adaptations are limited to few electrical interfaces and Generic adaptations. software modules mechanical and thermal validation is reached through moke up manufacturing, testing and mathematical model correlation. Platform electrical and software validation is reached through the implementation of a ESSVB (Electrical and Software System Validation Bench) on which each mission application software and electrical adaptation can be organisation, we Concerning validated. thought of an improvement by merging different program phases and reducing different WBS layers.
INTRODUCTION
the presents article This AEROSPATIALE ESPACE & DEFENSE industrial approach for the PROTEUS platform. The CNES initiated PROTEUS to define a new Low Earth Orbit Satellite class (500 kg) in order to increase SPACE Mission ACCESSIBILITY (300 M.F. Budget). Three major targets were then assigned to the PROTEUS platform. A very wide field of missions (orbits, attitude, instruments and launch vehicle compatibility) will be implemented on PROTEUS platform at a very attractive cost and within a 24 months delivery time. A cost driven system methodology has been established to produce a recurring platform at a very attractive cost. AEROSPATIALE conducted cost reductions engineering, organisation, analysis on procurement, quality and industrialisation.
Validation Operations manufacturers
Finally cost optimisation was made simultaneously on recurring and adaptation costs to the various PROTEUS missions.
&
Engineering, Testing, In orbit
Ground Satellite
- Customer, Prime, Equipment (no subsystem layer)
Regarding Quality, we thought of a tuning of applicable requirements according to industrial experience in space application and technical risks. 987
988
2.
Small Satellites for Earth Observation
KEY SATELLITE REQUIREMENTS
SYSTEM
The multimission objectives of PROTEUS are Following mandatory. requirements express their importance. PROTEUS Platform has been designed to be compatible with various orbits with altitude from 500 to 1500 km within any orbit plane inclination. The stowed platform has to be compatible with Small Launch Vehicle fairings diameters from 1.4 to 2.5 m. The platform will provide wide field of payload pointing, the accuracy of which is mission dependant. - Earth and Anti-Earth pointing
- Inertial pointing - Accuracy from 0.05” for optical mission to 0.2” for RF transmission mission. The platform will accommodate payload class up to 250 kg / 200 Watts. In order to verify the platform ability to accommodate various missions, 4 reference missions were assigned to PROTEUS platform. - TOPEX POSEIDON Follow On (JASON) - COROT - SAMBA - TROPIQUES Following table related requirements :
describes
their
989
Small Satellites for Earth Observation
3.
PROTEUS DESCRIPTION 3.1.
PLATFORM
Cost reduction methodology
Main driving cost reduction criteria for platform definition are as follow : to have generic covering the widest l
architectures application
platform field of
to reduce adaptable elements to I70 on board computer, payload mechanical interface and few software modules connected with payload management l to have a generic and robust satellite safe mode l to remind that sometimes hardware solution can save engineering effort and cost l
In addition, AEROSPATIALE has initiated a process for the reduction of the project team and the project administration procedures. The main areas of investigation can be summarised as following: - Design and Development with cost objectives: all technical decision will be made with economical criteria. This assumes to have large design margins to concentrate efforts on the cost - Clear Understanding and approved objectives: at the start of the project, the development objectives must be frozen, clearly exposed and approved by all parties. They will not be up-dated during the development phase. - Limitation of engineering paper work to the minimum - Hardware oriented development: it is assumed to prefer hardware testing for qualification, that will help to validate software models which will be used after qualification candidate for mission customisation.
- Light Project Review policy: all necessary analyses and verifications will be performed but thanks to a close steering board involving the CNES at the Programme Management Office level, the Project Reviews will be limited to the upper level and mainly to the operational aspects. - Light Verification Matrix, thanks to the robust design a light verification matrix will be implemented. - Equipment numbers: as a direct contributor to the satellite cost, the number and the type of equipment will be reduced as far as possible and procurement policy will be initiated for a whole family of platform and not on the case by case according to contract awarding. - Operational modes limitation: the main criteria being the autonomy and the associated cost, a limitation of the operational modes will help for the On Board Computer and On Board Software developments. - light documentation formalism: thanks to the localisation on one site of the system team, design team, AIT team, operations team and management of both the Industrial Prime Contractor and the Customer Agency, a light formalism is applied to the documentation file as all information is available at any time for any member of the project team 3.2.
Platform Description
The AEROSPATIALE ESPACE & DEFENSE PROTEUS Platform is 1 m framed cubic shape. It accommodates in its lower part mono propellant hydrazine units with a 40 litres tank and four 1N thrusters. The upper part offer a simple mechanical interface for payload fixation through four points. When payload topology allows it, the payload module structure will be built using the same platform main structure definition. The payload module can accommodate attitude control sensors when pointing accuracy field of view requirements are too much stringent.
990
Small Satellites for
The two wings solar array are attached near the satellite centre of mass with two one axis driving stepping motor mechanisms. This configuration allows very easy adaptation to orbit altitude with regard to disturbing torque. Platform attitude control will provide a second rotation around axis perpendicular to array driving solar mechanisms, allowing 90% recovery of sun light in case of non sun synchronous orbit. This insures inclination compatibility and a generic thermal control concept (same cold face what ever orbit inclination is). In orbit platform normal attitude control is based on a concept. Accurate GYRO-STELLAR for stability gyrometers are used requirements, attitude propagation and allow attitude updating at low frequency using non expensive simple wide field of view Star Sensor. Three small reactions wheels will
Earth Observation
generate torque for attitude command and are desaturated using magneto couplers. GPS receiver will provide satellite position for accurate orbit ephemerids determination and accurate on board time delivery. Satellite power is distributed thanks to unique non regulated primary bus power (21 / 35 Volts) using recurring SPOT 4 NiCd battery and classical Silicium cells installed on six 1.5 x 0.7 m solar array panels. Internal and external electrical interfaces are taken into account by the central computer DHU ( Data Handling Unit). On board software is run by DHU 3 1750 processor. DHU offers 2 Gbits payload data storage capacity End Of Life. A 650 kbits/s S Band QPSK down link is available for telemetry. A telecommand capacity is provided by a 4 kbitsls S Band up link.
External view of PROTEUS PLATFORM Bobine Senreur
Stelbife
Hybride
Dupkxer Filtre Emetteur QPSK Recepteur
PCE
Vanne de 8ewke @yd rzdne) Reaction
(Hydrzzine)
Small Satellites for Earth Observation
991
PROTEUS PLATFORM BLOCK DIAGRAM
PIFA 1
V
’ Alimentation
MdM UT/R
UT/N
<
’ IIF Charge utile
DHU AcquisitiorVCommande
- Distribution de puissance ’ ContrGle Thermique
Following table synthesises PROTEUS platform main characteristics and related performances. Satellite Mass
It is designed to be compatible with several existing or under development launchers such as : TAURUS, Delta Lite, LLV l&2, START, SHAVIT, EUROCKOT, SOYOUZ and ESL.
up to 550 kg 30 kg Hydrazine Capacity 0.9 Reliability over 3 years 5 Years Lifetime Bus Dry Mass : 2145 kg Bus Average
Power : 170 W
With its folded solar array, the platform remains in a 1.450 m diameter fairing (START & SHAVIT) and offer a 0.9 m diameter interface for adaptation on launch vehicle. It can accommodate payload up to 300 kg with average power up to 230 W (420 W on down/dusk orbit).
992 4.
Small Satellites for Earth Observation
DEVELOPMENT PLAN LOGIC OF PROTEUS PLATFORM PRODUCT LINE.
Development plan logic comes from the 3 major points of PROTEUS multimission character. - Software customisation and Payload electrical I/F adaptation ; - Wide field of launch vehicle mechanical environment ; - Wide field of in orbit thermal environment. It is then proposed : - the use of prototypes for the mechanical achieve the platform to qualification, Structural Model, and the thermal qualification, Thermal Model.The benefit will be twice, first it will allow to demonstrate real margins which would be adapted from case to case for cost reduction. In addition these models will establish a Data Base in order to validate Software analysis for future determination of performances without additional tests. - to take advantage of easy to good coupled architectural concept knowledge of FEM tools, mainly NASTRAN, to be in a position to apply a Proto Flight logic since the first operational mission and qualification by similarity for the following missions. - to limit the mechanical and thermal tests on the following missions only to the specific aspects of the Pay-Load needs. - to develop an Electrical and Software System Validation Bench (ESSVB), built around PROTEUS Platform central computer (EBB model) using simulated and stimulated peripheral units and/or Engineering Models units. Satellite environment and dynamics are software simulated. The ESSVB is used for each new satellite application for electrical and software validation.
5.
CONCLUSION
AEROSPATIALE expertise in space industrialisation has been applied to PROTEUS technical definition. The selected technical solution allows cost reduction for PROTEUS adaptation and PROTEUS recurring production. The complete process for PROTEUS production has been reviewed with a cost/risk approach. Finally, after a national competition, CNES selected AEROSPATIALE within a partnership relation for the development of part of PROTEUS Space Segment and the TOPEX Follow On application JASON 1.
A LOW COST MULTIMISSION BUS FOR SMALL SATELLITES APPLICATIONS Philippe BERTHEUX, Francis DOUILLET, Jean Claude CHIARINI AEROSPATIALE CANNES 100 Bd du Midi, Cannes La Bocca, BP-99 06322 Cedex ABSTRACT - This article presents the AEROSPATIALE ESPACE & DEFENSE industrial approach for the CNES PROTEUS platform. Three major targets were assigned to the PROTEUS plat$onn. A very wide field of missions (orbits, attitude, instruments and launch vehicle compatibility) will be implemented on PROTEUS platform at a very attractive cost and within a 24 months delivery time. A cost driven system methodology has been established to produce a recurring platform at a very attractive cost. Cost reductions choices were analysed and selected on organisation, engineering, procurement, quality and industrialisation. 01997
1.
Published
by Elsevier
Science
Ltd.
the platform Technically, architectures are generic. Adaptations are limited to few electrical interfaces and Generic adaptations. software modules mechanical and thermal validation is reached through moke up manufacturing, testing and mathematical model correlation. Platform electrical and software validation is reached through the implementation of a ESSVB (Electrical and Software System Validation Bench) on which each mission application software and electrical adaptation can be organisation, we Concerning validated. thought of an improvement by merging different program phases and reducing different WBS layers.
INTRODUCTION
the presents article This AEROSPATIALE ESPACE & DEFENSE industrial approach for the PROTEUS platform. The CNES initiated PROTEUS to define a new Low Earth Orbit Satellite class (500 kg) in order to increase SPACE Mission ACCESSIBILITY (300 M.F. Budget). Three major targets were then assigned to the PROTEUS platform. A very wide field of missions (orbits, attitude, instruments and launch vehicle compatibility) will be implemented on PROTEUS platform at a very attractive cost and within a 24 months delivery time. A cost driven system methodology has been established to produce a recurring platform at a very attractive cost. AEROSPATIALE conducted cost reductions engineering, organisation, analysis on procurement, quality and industrialisation.
Validation Operations manufacturers
Finally cost optimisation was made simultaneously on recurring and adaptation costs to the various PROTEUS missions.
&
Engineering, Testing, In orbit
Ground Satellite
- Customer, Prime, Equipment (no subsystem layer)
Regarding Quality, we thought of a tuning of applicable requirements according to industrial experience in space application and technical risks. 987
988
2.
Small Satellites for Earth Observation
KEY SATELLITE REQUIREMENTS
SYSTEM
The multimission objectives of PROTEUS are Following mandatory. requirements express their importance. PROTEUS Platform has been designed to be compatible with various orbits with altitude from 500 to 1500 km within any orbit plane inclination. The stowed platform has to be compatible with Small Launch Vehicle fairings diameters from 1.4 to 2.5 m. The platform will provide wide field of payload pointing, the accuracy of which is mission dependant. - Earth and Anti-Earth pointing
- Inertial pointing - Accuracy from 0.05” for optical mission to 0.2” for RF transmission mission. The platform will accommodate payload class up to 250 kg / 200 Watts. In order to verify the platform ability to accommodate various missions, 4 reference missions were assigned to PROTEUS platform. - TOPEX POSEIDON Follow On (JASON) - COROT - SAMBA - TROPIQUES Following table related requirements :
describes
their
989
Small Satellites for Earth Observation
3.
PROTEUS DESCRIPTION 3.1.
PLATFORM
Cost reduction methodology
Main driving cost reduction criteria for platform definition are as follow : to have generic covering the widest l
architectures application
platform field of
to reduce adaptable elements to I70 on board computer, payload mechanical interface and few software modules connected with payload management l to have a generic and robust satellite safe mode l to remind that sometimes hardware solution can save engineering effort and cost l
In addition, AEROSPATIALE has initiated a process for the reduction of the project team and the project administration procedures. The main areas of investigation can be summarised as following: - Design and Development with cost objectives: all technical decision will be made with economical criteria. This assumes to have large design margins to concentrate efforts on the cost - Clear Understanding and approved objectives: at the start of the project, the development objectives must be frozen, clearly exposed and approved by all parties. They will not be up-dated during the development phase. - Limitation of engineering paper work to the minimum - Hardware oriented development: it is assumed to prefer hardware testing for qualification, that will help to validate software models which will be used after qualification candidate for mission customisation.
- Light Project Review policy: all necessary analyses and verifications will be performed but thanks to a close steering board involving the CNES at the Programme Management Office level, the Project Reviews will be limited to the upper level and mainly to the operational aspects. - Light Verification Matrix, thanks to the robust design a light verification matrix will be implemented. - Equipment numbers: as a direct contributor to the satellite cost, the number and the type of equipment will be reduced as far as possible and procurement policy will be initiated for a whole family of platform and not on the case by case according to contract awarding. - Operational modes limitation: the main criteria being the autonomy and the associated cost, a limitation of the operational modes will help for the On Board Computer and On Board Software developments. - light documentation formalism: thanks to the localisation on one site of the system team, design team, AIT team, operations team and management of both the Industrial Prime Contractor and the Customer Agency, a light formalism is applied to the documentation file as all information is available at any time for any member of the project team 3.2.
Platform Description
The AEROSPATIALE ESPACE & DEFENSE PROTEUS Platform is 1 m framed cubic shape. It accommodates in its lower part mono propellant hydrazine units with a 40 litres tank and four 1N thrusters. The upper part offer a simple mechanical interface for payload fixation through four points. When payload topology allows it, the payload module structure will be built using the same platform main structure definition. The payload module can accommodate attitude control sensors when pointing accuracy field of view requirements are too much stringent.
990
Small Satellites for
The two wings solar array are attached near the satellite centre of mass with two one axis driving stepping motor mechanisms. This configuration allows very easy adaptation to orbit altitude with regard to disturbing torque. Platform attitude control will provide a second rotation around axis perpendicular to array driving solar mechanisms, allowing 90% recovery of sun light in case of non sun synchronous orbit. This insures inclination compatibility and a generic thermal control concept (same cold face what ever orbit inclination is). In orbit platform normal attitude control is based on a concept. Accurate GYRO-STELLAR for stability gyrometers are used requirements, attitude propagation and allow attitude updating at low frequency using non expensive simple wide field of view Star Sensor. Three small reactions wheels will
Earth Observation
generate torque for attitude command and are desaturated using magneto couplers. GPS receiver will provide satellite position for accurate orbit ephemerids determination and accurate on board time delivery. Satellite power is distributed thanks to unique non regulated primary bus power (21 / 35 Volts) using recurring SPOT 4 NiCd battery and classical Silicium cells installed on six 1.5 x 0.7 m solar array panels. Internal and external electrical interfaces are taken into account by the central computer DHU ( Data Handling Unit). On board software is run by DHU 3 1750 processor. DHU offers 2 Gbits payload data storage capacity End Of Life. A 650 kbits/s S Band QPSK down link is available for telemetry. A telecommand capacity is provided by a 4 kbitsls S Band up link.
External view of PROTEUS PLATFORM Bobine Senreur
Stelbife
Hybride
Dupkxer Filtre Emetteur QPSK Recepteur
PCE
Vanne de 8ewke @yd rzdne) Reaction
(Hydrzzine)
Small Satellites for Earth Observation
991
PROTEUS PLATFORM BLOCK DIAGRAM
PIFA 1
V
’ Alimentation
MdM UT/R
UT/N
<
’ IIF Charge utile
DHU AcquisitiorVCommande
- Distribution de puissance ’ ContrGle Thermique
Following table synthesises PROTEUS platform main characteristics and related performances. Satellite Mass
It is designed to be compatible with several existing or under development launchers such as : TAURUS, Delta Lite, LLV l&2, START, SHAVIT, EUROCKOT, SOYOUZ and ESL.
up to 550 kg 30 kg Hydrazine Capacity 0.9 Reliability over 3 years 5 Years Lifetime Bus Dry Mass : 2145 kg Bus Average
Power : 170 W
With its folded solar array, the platform remains in a 1.450 m diameter fairing (START & SHAVIT) and offer a 0.9 m diameter interface for adaptation on launch vehicle. It can accommodate payload up to 300 kg with average power up to 230 W (420 W on down/dusk orbit).
992 4.
Small Satellites for Earth Observation
DEVELOPMENT PLAN LOGIC OF PROTEUS PLATFORM PRODUCT LINE.
Development plan logic comes from the 3 major points of PROTEUS multimission character. - Software customisation and Payload electrical I/F adaptation ; - Wide field of launch vehicle mechanical environment ; - Wide field of in orbit thermal environment. It is then proposed : - the use of prototypes for the mechanical achieve the platform to qualification, Structural Model, and the thermal qualification, Thermal Model.The benefit will be twice, first it will allow to demonstrate real margins which would be adapted from case to case for cost reduction. In addition these models will establish a Data Base in order to validate Software analysis for future determination of performances without additional tests. - to take advantage of easy to good coupled architectural concept knowledge of FEM tools, mainly NASTRAN, to be in a position to apply a Proto Flight logic since the first operational mission and qualification by similarity for the following missions. - to limit the mechanical and thermal tests on the following missions only to the specific aspects of the Pay-Load needs. - to develop an Electrical and Software System Validation Bench (ESSVB), built around PROTEUS Platform central computer (EBB model) using simulated and stimulated peripheral units and/or Engineering Models units. Satellite environment and dynamics are software simulated. The ESSVB is used for each new satellite application for electrical and software validation.
5.
CONCLUSION
AEROSPATIALE expertise in space industrialisation has been applied to PROTEUS technical definition. The selected technical solution allows cost reduction for PROTEUS adaptation and PROTEUS recurring production. The complete process for PROTEUS production has been reviewed with a cost/risk approach. Finally, after a national competition, CNES selected AEROSPATIALE within a partnership relation for the development of part of PROTEUS Space Segment and the TOPEX Follow On application JASON 1.