Changes between Version 27 and Version 28 of TBR/UserApp/Space/Proba_2


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Timestamp:
Nov 30, 2011, 12:14:16 AM (8 years ago)
Author:
Iliyankatsarski
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  • TBR/UserApp/Space/Proba_2

    v27 v28  
    376376
    377377For further info [http://ilrs.gsfc.nasa.gov/docs/ESA4S_06_11d.pdf PROBA-2 MISSION AND NEW TECHNOLOGIES OVERVIEW]
     378
     379= RetroReflector Array (RRA) Characteristics: =
     380
     381
     382PROBA-2 will use the same retroreflector package as was installed on Cryosat-1.
     383More information about the retroreflector characteristics can be found in the document "CryoSat-LRR-01 Laser Retro Reflector Technical Description" (V. Shargorodsky/2002).
     384PROBA-2 Retroreflector Information Form (29 August 2008, PDF):
     385
     386(from http://ilrs.gsfc.nasa.gov/satellite_missions/ilrssupretro.html)
     387Satellite name Name: PROBA-2
     388
     389Contact for retroreflector information: Stefano Santandrea, ESA/ESTEC
     390Phone number: +31 (71) 565-4407
     391E-mail address: stefano.santandrea @ esa.int
     392
     393A prerequisite for accurate reduction of laser range observations is a complete set of pre-launch parameters that define the characteristics and location of the LRA on the satellite. The set of parameters should include a general description of the array, including references to any ground-tests that may have been carried out, array manufacturer and whether the array type has been used in previous satellite missions. So the following information is requested.
     394
     3951. Array type (spherical, hexagonal, planar, etc.), to include a diagram or photograph: 7 reflectors (1 central and 6 lateral in a circular arrangement) mounted on a flattened cone. See picture for further details.
     3962. Array manufacturer: Scientific Research Institute for Precision Instruments, Moscow
     3973. Link (URL or reference) to any ground-tests that were carried out on the array:
     3984. Other missions using this LRA design and/or type of cubes: CryoSat-1/2, GOCE
     399
     400For accurate orbital analysis it is essential that full information is available in order that a model of the 3-dimensional position of the satellite centre of mass may be referred to the location in space at which the laser range measurements are made. To achieve this, the 3-D location of the LRA phase centre must be specified in a satellite fixed reference frame with respect to the satellite's mass centre. In practice this means that the following parameters must be available at mm accuracy or better.
     401
     4025. 3-D location (possibly time-dependent) of the satellite's mass centre relative to a satellite-based origin:
     403Spacecraft CoM (X,Y,Z) = (-0.0160m,-0.0060m,+0.3810m)
     404
     4056. 3-D location of the phase centre of the LRA relative to a satellite-based origin:
     406LRA CoM (X,Y,Z) = (+0.2085m,-0.2390m,+0.0102m), LRA MSC (X,Y,Z) = (+0.2085m,-0.2390m,+0.0300m)
     407Note: the LRA center-of-mass is offset by 19.8 mm from the reference point (= mounting surface center, MSC) along the boresight of the central reflector. The range finding correction relative to the mounting surface center amounts to +19+/-6 mm, and depends on the angle of position and the spacecraft bearing relative to station SLR, and shall be added to the measured range.
     408
     409However, in order to achieve (6) if it is not directly specified (the ideal case) by the satellite manufacturer, and as an independent check, the following information must be supplied prior to launch.
     410
     4117. Position and orientation of the LRA reference point (LRA mass-centre or marker on LRA assembly) relative to a satellite-based origin:
     4128. Position (xyz) of the centre of the front face of each corner cube within the LRA assembly, with respect to the LRA reference point and including information of amount of recession of front faces of cubes:
     413(dX,dY,dZ)_0 = (+0.000m,-0.000m,-0.0480m)
     414(dX,dY,dZ)_i = ( +0.0455*cos(p/3*(i-1)),-0.0455*sin(p/3*(i-1)),-0.0285m), i=1,...,6
     4159. Orientation of each cube within the LRA assembly (three angles for each cube): See design drawing.
     41610. Shape and size of each corner cube, especially the height:
     41711. Material from which the cubes are manufactured (e.g. quartz): fused silica with aluminium-coated reflecting prism faces
     41812. Refractive index of the cube material, as a function of wavelength ? (micron):
     41913. Dihedral angle offset(s) and manufacturing tolerance:
     42014. Radius of curvature of front surfaces of cubes, if applicable:
     42115. Flatness of cubes' surfaces (as a fraction of wavelength):
     42216. Whether or not the cubes are coated and with what material:
     423= Proba2 Station DATA =
     424
     425
     426timespan is October 1, 2010 through September 30, 2011
     427You can find the station data [http://ilrs.gsfc.nasa.gov/satellite_missions/list_of_satellites/prb2_stadata.html here]
     428
     429= RTEMS - part of the ESA =
     430
     431
     432RTEMS validation and tools
     433 
     434Saab Space AB performed a validation of the real-time operating system RTEMS. Since it is available for many different targets and includes a multitude of functionality, ranging from I/O drivers to file-systems and beyond, it was agreed to only focus on the parts that were applicable for European space community applications. This implied that only the ERC32 target and a limited sub-set of the configurable RTEMS managers had to be considered.
     435
     436Subsequently, Edisoft has reached an agreement with OAR to implement an RTEMS maintenance centre (see related link) in Europe. Edisoft has complemented the validation and the toolset associated with RTEMS for the specific needs of the European space industry. Gaisler Research also provides services based around RTEMS on ERC32 and Leon.
     437
     438RTEMS has already been used in several space applications, in particular FedSat (a scientific Research and Development microsatellite), the Surrey's Solid State Data Recorder (a component used in the Disaster Monitoring Constellation), ChipSat (a System-on-Chip architecture), the Electra UHF antenna of the Mars Reconnaissance Orbiter and in the Galileo GIOVE-A and Herschel-Planck satellites.
    378439= Providing flight opportunities =
    379440
     
    569630
    570631For further info [http://events.eoportal.org/presentations/7111/10001905.html PROBA-V (Project for On-Board Autonomy - Vegetation)]
    571 = RetroReflector Array (RRA) Characteristics: =
    572 
    573 
    574 PROBA-2 will use the same retroreflector package as was installed on Cryosat-1.
    575 More information about the retroreflector characteristics can be found in the document "CryoSat-LRR-01 Laser Retro Reflector Technical Description" (V. Shargorodsky/2002).
    576 PROBA-2 Retroreflector Information Form (29 August 2008, PDF):
    577 
    578 (from http://ilrs.gsfc.nasa.gov/satellite_missions/ilrssupretro.html)
    579 Satellite name Name: PROBA-2
    580 
    581 Contact for retroreflector information: Stefano Santandrea, ESA/ESTEC
    582 Phone number: +31 (71) 565-4407
    583 E-mail address: stefano.santandrea @ esa.int
    584 
    585 A prerequisite for accurate reduction of laser range observations is a complete set of pre-launch parameters that define the characteristics and location of the LRA on the satellite. The set of parameters should include a general description of the array, including references to any ground-tests that may have been carried out, array manufacturer and whether the array type has been used in previous satellite missions. So the following information is requested.
    586 
    587 1. Array type (spherical, hexagonal, planar, etc.), to include a diagram or photograph: 7 reflectors (1 central and 6 lateral in a circular arrangement) mounted on a flattened cone. See picture for further details.
    588 2. Array manufacturer: Scientific Research Institute for Precision Instruments, Moscow
    589 3. Link (URL or reference) to any ground-tests that were carried out on the array:
    590 4. Other missions using this LRA design and/or type of cubes: CryoSat-1/2, GOCE
    591 
    592 For accurate orbital analysis it is essential that full information is available in order that a model of the 3-dimensional position of the satellite centre of mass may be referred to the location in space at which the laser range measurements are made. To achieve this, the 3-D location of the LRA phase centre must be specified in a satellite fixed reference frame with respect to the satellite's mass centre. In practice this means that the following parameters must be available at mm accuracy or better.
    593 
    594 5. 3-D location (possibly time-dependent) of the satellite's mass centre relative to a satellite-based origin:
    595 Spacecraft CoM (X,Y,Z) = (-0.0160m,-0.0060m,+0.3810m)
    596 
    597 6. 3-D location of the phase centre of the LRA relative to a satellite-based origin:
    598 LRA CoM (X,Y,Z) = (+0.2085m,-0.2390m,+0.0102m), LRA MSC (X,Y,Z) = (+0.2085m,-0.2390m,+0.0300m)
    599 Note: the LRA center-of-mass is offset by 19.8 mm from the reference point (= mounting surface center, MSC) along the boresight of the central reflector. The range finding correction relative to the mounting surface center amounts to +19+/-6 mm, and depends on the angle of position and the spacecraft bearing relative to station SLR, and shall be added to the measured range.
    600 
    601 However, in order to achieve (6) if it is not directly specified (the ideal case) by the satellite manufacturer, and as an independent check, the following information must be supplied prior to launch.
    602 
    603 7. Position and orientation of the LRA reference point (LRA mass-centre or marker on LRA assembly) relative to a satellite-based origin:
    604 8. Position (xyz) of the centre of the front face of each corner cube within the LRA assembly, with respect to the LRA reference point and including information of amount of recession of front faces of cubes:
    605 (dX,dY,dZ)_0 = (+0.000m,-0.000m,-0.0480m)
    606 (dX,dY,dZ)_i = ( +0.0455*cos(p/3*(i-1)),-0.0455*sin(p/3*(i-1)),-0.0285m), i=1,...,6
    607 9. Orientation of each cube within the LRA assembly (three angles for each cube): See design drawing.
    608 10. Shape and size of each corner cube, especially the height:
    609 11. Material from which the cubes are manufactured (e.g. quartz): fused silica with aluminium-coated reflecting prism faces
    610 12. Refractive index of the cube material, as a function of wavelength ? (micron):
    611 13. Dihedral angle offset(s) and manufacturing tolerance:
    612 14. Radius of curvature of front surfaces of cubes, if applicable:
    613 15. Flatness of cubes' surfaces (as a fraction of wavelength):
    614 16. Whether or not the cubes are coated and with what material:
    615 = Proba2 Station DATA =
    616 
    617 
    618 timespan is October 1, 2010 through September 30, 2011
    619 You can find the station data [http://ilrs.gsfc.nasa.gov/satellite_missions/list_of_satellites/prb2_stadata.html here]
    620 
    621 = RTEMS - part of the ESA =
    622 
    623 
    624 RTEMS validation and tools
    625  
    626 Saab Space AB performed a validation of the real-time operating system RTEMS. Since it is available for many different targets and includes a multitude of functionality, ranging from I/O drivers to file-systems and beyond, it was agreed to only focus on the parts that were applicable for European space community applications. This implied that only the ERC32 target and a limited sub-set of the configurable RTEMS managers had to be considered.
    627 
    628 Subsequently, Edisoft has reached an agreement with OAR to implement an RTEMS maintenance centre (see related link) in Europe. Edisoft has complemented the validation and the toolset associated with RTEMS for the specific needs of the European space industry. Gaisler Research also provides services based around RTEMS on ERC32 and Leon.
    629 
    630 RTEMS has already been used in several space applications, in particular FedSat (a scientific Research and Development microsatellite), the Surrey's Solid State Data Recorder (a component used in the Disaster Monitoring Constellation), ChipSat (a System-on-Chip architecture), the Electra UHF antenna of the Mars Reconnaissance Orbiter and in the Galileo GIOVE-A and Herschel-Planck satellites.
    631632= External links =
    632633