Changes between Version 22 and Version 23 of UserApp/Proba-V


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Timestamp:
Dec 8, 2011, 2:44:27 AM (8 years ago)
Author:
JoelSherrill
Comment:

Fixed figures to have captions and removed what I think were a cut and paste artifact

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  • UserApp/Proba-V

    v22 v23  
    5858The PROBA-V (Vegetation) mission definition is an attempt, spearheaded by ESA and CNES, to accommodate an improved smaller version of the large VGT (Vegetation) optical instrument of SPOT-4 and SPOT-5 mission heritage on a small satellite bus, such as the one of PROBA-2.
    5959
    60 As of 2008, small satellite technologies have reached a level of maturity and reliability to be used as a platform for an operational Earth observation mission. Furthermore, advancements in the techniques of detectors, optics fabrication and metrology are considered sufficiently mature to permit the design of a compact multispectral optical instrument. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10)
     60As of 2008, small satellite technologies have reached a level of maturity and reliability to be used as a platform for an operational Earth observation mission. Furthermore, advancements in the techniques of detectors, optics fabrication and metrology are considered sufficiently mature to permit the design of a compact multispectral optical instrument.
    6161
    6262The C/D Phase started in July 2010. The system CDR (Critical Design Review) took place in the spring of 2011. The acceptance review is planned for Dec. 2011 and the flight acceptance review is planned for the spring of 2012.. ESA is responsible for the overall mission, the technological payloads and for the launcher selection.
     
    7777As of 2008, a Vegetation archive of 10 years of consistent global data sets has been established permitting researchers access on a long-term basis. The SPOT-5 operational lifetime is estimated to expire in 2012. Pleiades, the next French satellite for Earth Observation, is solely dedicated to high-resolution imaging (on a fairly narrow swath) and will not embark any instrument providing vegetation data.
    7878
    79 Since the SPOT series spacecraft will not be continued and the SPOT-5 spacecraft will eventually fail — there is of course a great interest in the EO user community to the Vegetation observation in the context of a smaller mission, affordable to all concerned. 11)
     79Since the SPOT series spacecraft will not be continued and the SPOT-5 spacecraft will eventually fail — there is of course a great interest in the EO user community to the Vegetation observation in the context of a smaller mission, affordable to all concerned.
    8080
    8181PROBA-V will continue the production of Vegetation products exploiting advanced small satellite technology. However, this implies in particular a redesign of the Vegetation payload into a much smaller unit to be able to accommodate it onto the PROBA bus.
     
    9999An extensive feasibility study and trade-off work was undertaken to identify a solution that could meet not only the technical challenges, but that could also be developed and tested within a tight budget of a small satellite mission.
    100100
    101 The PROBA-V project of ESA includes the Space Segment (platform contract award to QinetiQ Space NV of Kruibeke, Belgium - formerly Verhaert), the Mission Control Center (Redu, Belgium) and the User Segment (data processing facility) at VITO NV. VITO (Vlaamse instelling voor technologisch onderzoek - Flemish Institute for Technological Research) is located in northern Belgium. VITO’s processing center of VGT1 and 2 data (SPOT-4 and SPOT-5) is operational since 1999. VITO is also the prime investigator and data service provider of PROBA-V for the user community including product quality control. 14)
     101The PROBA-V project of ESA includes the Space Segment (platform contract award to QinetiQ Space NV of Kruibeke, Belgium - formerly Verhaert), the Mission Control Center (Redu, Belgium) and the User Segment (data processing facility) at VITO NV. VITO (Vlaamse instelling voor technologisch onderzoek - Flemish Institute for Technological Research) is located in northern Belgium. VITO’s processing center of VGT1 and 2 data (SPOT-4 and SPOT-5) is operational since 1999. VITO is also the prime investigator and data service provider of PROBA-V for the user community including product quality control.
    102102= Implementation schedule: =
    103103
     
    112112
    113113{| align="center"
     114|+'''PROBA-V project organization (image credit: ESA)'''
    114115|-
    115116|[wiki:File:ProbaV_Auto11.jpeg File:ProbaV Auto11.jpeg]
    116117|}
    117 
    118 Figure 2: PROBA-V project organization (image credit: ESA, Ref. 9)
    119118= Spacecraft: =
    120119
     
    122121An industrial team, led by QinetiQ Space NV (Belgium), is supported by several European subcontractors and suppliers, and is responsible for the development of the flight satellite platform, the vegetation payload and the Ground Segment.
    123122
    124 The spacecraft bus (fully redundant) is of heritage from the PROBA-1 and PROBA-2 missions (structure, avionics, AOCS, OBS with minor modifications). The PROBA-V spacecraft has a total mass of ~160 kg, and a volume of 80 cm x 80 cm x 100 cm. The three-axis stabilized platform is designed for a mission lifetime of 2.5 years (Ref. 7). 15)
     123The spacecraft bus (fully redundant) is of heritage from the PROBA-1 and PROBA-2 missions (structure, avionics, AOCS, OBS with minor modifications). The PROBA-V spacecraft has a total mass of ~160 kg, and a volume of 80 cm x 80 cm x 100 cm. The three-axis stabilized platform is designed for a mission lifetime of 2.5 years.
    125124
    126125The spacecraft resources management is built around ADPMS (Advanced Data and Power Management System), which is currently flying on PROBA-2. The data handling part of ADPMS is partitioned using compact PCI modules. A cold redundant mass memory module of 16 Gbit is foreseen for PROBA-V. The newly developed mass memory will use NAND flash technology.
     
    131130
    132131{| border="1"
    133 |+ '''Table 1: Overview of PROBA-V subsystems'''
     132|+ '''Overview of PROBA-V subsystems'''
    134133|-
    135134|Avionics
     
    168167
    169168{| align="center"
     169|+'''PROBA-V spacecraft accommodation (image credit: QinetiQ Space)'''
    170170|-
    171171|[wiki:File:ProbaV_Auto10.jpeg File:ProbaV Auto10.jpeg]
    172172|}
    173 
    174 Figure 3: PROBA-V spacecraft accommodation (image credit: QinetiQ Space)== AOCS (Attitude and Orbit Control Subsystem)  ==
    175 
    176 AOCS (Attitude and Orbit Control Subsystem) provides three-axis attitude control including high accuracy pointing and maneuvering in different spacecraft attitude modes. The AOCS SW is an extension of the one of PROBA-2, including the following algorithms required by the on-board autonomous mission and payload management: 16)
     173== AOCS (Attitude and Orbit Control Subsystem)  ==
     174
     175AOCS (Attitude and Orbit Control Subsystem) provides three-axis attitude control including high accuracy pointing and maneuvering in different spacecraft attitude modes. The AOCS SW is an extension of the one of PROBA-2, including the following algorithms required by the on-board autonomous mission and payload management:
    177176
    178177 *  Prediction of land/sea transitions using a land sea mask to reduce the amount of data generated
     
    200199 *  The Inertial mode coupled with an inertial scanning of the Moon at a fixed rate is used for monthly radiometric full moon instrument calibration purposes. The pointing towards the moon takes 2.5 min, 9 min for scanning the moon and 2.5 min to return to nominal observation mode. It is sufficient to have the moon in the FOV of the SI (Spectral Imager) for a number of pixels.
    201200
    202 Beyond the technology demonstration through the PROBA program, it is also noted that the AOCS software technology developed in the course of this program is now the baseline of the AOCS of a major operational mission of the GMES (Global Monitoring for Environment and Security) program: Sentinel-3. NGC Aerospace Ltd (NGC) of Sherbrooke, (Québec), Canada was responsible for the design, implementation and validation of the autonomous GNC (Guidance, Navigation and Control) algorithms implemented as part of the AOCS software of PROBA-1 and PROBA-2. NGC has the same responsibilities for the PROBA-V mission (Ref. 16).
     201Beyond the technology demonstration through the PROBA program, it is also noted that the AOCS software technology developed in the course of this program is now the baseline of the AOCS of a major operational mission of the GMES (Global Monitoring for Environment and Security) program: Sentinel-3. NGC Aerospace Ltd (NGC) of Sherbrooke, (Québec), Canada was responsible for the design, implementation and validation of the autonomous GNC (Guidance, Navigation and Control) algorithms implemented as part of the AOCS software of PROBA-1 and PROBA-2. NGC has the same responsibilities for the PROBA-V mission.
    203202
    204203EPS (Electric Power Subsystem): The PVA (Photo-Voltaic Array) uses GaAs triple junction cells with an of efficiency of 28%. To obtain the operating voltage of 31.5 V, 18 cells are included in each string in series with a blocking diode. The PVA consists of a total of 25 solar strings taken into account the loss of one string on the most contributing PVA panel. The average solar string power under EOL conditions (summer solstice and T = 40°C) yields 12.8 W. The maximal incoming power at EOL during an orbit is 144 W. The energy budget for PROBA-V is derived for a bus power consumption of 140 W assuming a worst case day in the summer and while not taken into account the effect of albedo. A worst case power budget analysis indicated a maximum capacity discharge of 1.66 Ah. Use of a Li-ion battery. The battery cells provide a capacity of 1.5 Ah per string. The PROBA-V battery is sized to 12 Ah taking into account capacity fading and loss of a string.
     
    243242
    244243
    245 The development of the new X-band transmitter is based almost exclusively on COTS components to achieve at the same time high performances and low recurrent cost. The transmitter also features an innovative functionality with an on-board programmable RF output power from 1-10 W which allows to match finely with the chosen bit rate, and to reduce as much as possible the margins of the link budget and therefore the consumption power. PROBA-V is the first mission to use this newly developed transmitter. The transmitter has a mass of 1 kg, a size of 160 mm x 115 mm x 46 mm, an in-orbit life time of 5 years, and a radiation hardness of 10 krad. Data rates from 10-100 Mbit/s are available. The X-band transmitter was manufactured by TES Electonic Solutions of Bruz, France. 18)
    246 
    247 
    248 {| align="center"
    249 |+'''Figure 4: Overview of the transmitter architecture (CNES, TES)'''
     244The development of the new X-band transmitter is based almost exclusively on COTS components to achieve at the same time high performances and low recurrent cost. The transmitter also features an innovative functionality with an on-board programmable RF output power from 1-10 W which allows to match finely with the chosen bit rate, and to reduce as much as possible the margins of the link budget and therefore the consumption power. PROBA-V is the first mission to use this newly developed transmitter. The transmitter has a mass of 1 kg, a size of 160 mm x 115 mm x 46 mm, an in-orbit life time of 5 years, and a radiation hardness of 10 krad. Data rates from 10-100 Mbit/s are available. The X-band transmitter was manufactured by TES Electonic Solutions of Bruz, France.
     245
     246
     247{| align="center"
     248|+'''Overview of the transmitter architecture (CNES, TES)'''
    250249|-
    251250|[wiki:File:ProbaV_AutoF.jpeg? File:ProbaV AutoF.jpeg?]|}
     
    253252
    254253{| align="center"
    255 |+'''Figure 5: Photo of the X-band transmitter (image credit: CNES, ESA)'''
     254|+'''Photo of the X-band transmitter (image credit: CNES, ESA)'''
    256255|-
    257256|[wiki:File:ProbaV_AutoE.jpeg File:ProbaV AutoE.jpeg]
     
    260259
    261260
    262 The PROBA-Vegetation payload is a multispectral spectrometer with 4 spectral bands and with a very large swath of 2285 km to guarantee daily coverage above 35 latitude. The payload consists of 3 identical SI (Spectral Imagers), each with a very compact TMA telescope. Each TMA, having a FOV of 34º, contains 4 spectral bands: 3 bands in the visible range and one band in the SWIR spectral range. 19) 20)
     261The PROBA-Vegetation payload is a multispectral spectrometer with 4 spectral bands and with a very large swath of 2285 km to guarantee daily coverage above 35 latitude. The payload consists of 3 identical SI (Spectral Imagers), each with a very compact TMA telescope. Each TMA, having a FOV of 34º, contains 4 spectral bands: 3 bands in the visible range and one band in the SWIR spectral range.
    263262
    264263VGT-P is restricted to imaging land and dedicated calibration zones. On-board the spacecraft there is for each spectral imager a land sea mask that is provided by the PI (Principal Investigator). The land sea mask removes the pixels that contain only sea and it dictates when each SI should be in imaging mode.
     
    271270
    272271{| align="center"
    273 |+'''Figure 6: Conceptual accommodation of the VGT-P inside the PROBA-V spacecraft (image credit: OIP, ESA)'''
     272|+'''Conceptual accommodation of the VGT-P inside the PROBA-V spacecraft (image credit: OIP, ESA)'''
    274273|-
    275274|[wiki:File:ProbaV_AutoD.jpeg File:ProbaV AutoD.jpeg]
     
    279278
    280279{| align="center"
    281 |+'''Figure 7: Block diagram of the VGT-P (image credit: OIP)'''
     280|+'''Block diagram of the VGT-P (image credit: OIP)'''
    282281|-
    283282|[wiki:File:ProbaV_AutoC.jpeg File:ProbaV AutoC.jpeg]
     
    306305
    307306{| border="1"
    308 |+ '''Table 4: Performance requirements of MTF'''
     307|+ '''Performance requirements of MTF'''
    309308|-
    310309|Band
     
    335334
    336335{| align="center"
    337 |+'''Figure 8: Optical design concept of the TMA (ray tracing diagram), image credit: OIP'''
     336|+'''Optical design concept of the TMA (ray tracing diagram), image credit: OIP'''
    338337|-
    339338|[wiki:File:ProbaV_AutoB.jpeg File:ProbaV AutoB.jpeg]
     
    347346
    348347{| align="center"
    349 |+'''Figure 9: Proba-V TMA preliminary baffles layout (image credit: CSL, OIP, ESA/ESTEC)'''
     348|+'''Proba-V TMA preliminary baffles layout (image credit: CSL, OIP, ESA/ESTEC)'''
    350349|-
    351350|[wiki:File:ProbaV_AutoA.jpeg File:ProbaV AutoA.jpeg]
     
    369368
    370369{| align="center"
    371 |+'''Figure 11: Schematic view of of the mechanically butted SWIR detector array (image credit: OIP, Xenics)'''
     370|+'''Schematic view of of the mechanically butted SWIR detector array (image credit: OIP, Xenics)'''
    372371|-
    373372|[wiki:File:ProbaV_Auto8.jpeg File:ProbaV Auto8.jpeg]
     
    381380
    382381{| align="center"
    383 |+'''Figure 13: Photo of the fully assembled FPA in its package (image credit: OIP, Xenics)'''
     382|+'''Photo of the fully assembled FPA in its package (image credit: OIP, Xenics)'''
    384383|-
    385384|[wiki:File:ProbaV_Auto6.jpeg File:ProbaV Auto6.jpeg]