STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR1 SEP Mechanical Design Sandy Shuman, GSFC ) Tycho von Rosenvinge, GSFC

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR2 SIT Instrument Assembly Telescope HVPS Electronics Enclosure Actuator Door Assembly

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR3 SIT Enclosures High Voltage enclosure is being designed by GSFC Electronics enclosure is being designed by GSFC

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR4 SIT Telescope Door Single re-settable thermal actuator purchased from TiNi Aerospace. One-time opening door is needed for acoustic seal on launch and as a sun blocker during S/C early mission maneuvers. Door protects a thin Nickel window at the front of the telescope. Single-hinged door with a pre-tensioned spring and hard stop point.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR5 SIT Mechanical Component Status The SIT Telescope design is a minor variation on the STEP telescope built earlier for WIND/EPACT. Only the SIT door actuator and mechanical enclosures for the electronics are new. Designs for new mechanical pieces for SIT are 75% complete. Designs for retro-fit of telescope are 50% complete. Drawings for SIT overall are 90% complete, new components 40%.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR6 Main SEP Assembly LET Telescope HET Telescope SEP Central Enclosure Analog/ Post-Regulator Electronics Board Digital Logic Electronics Board LVPS HV Bias Supply Behind S/C configuration shown

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR7 Main SEP Electronics Assembly Electronics box is made up of 4 major components, the SEP Central Enclosure, the LVPS, the HET Enclosure and the LET Bracket Base. All interfacing walls, when attached will provide a continuous RF shield for internal electronics. Internal shielding between critical components will create separate shielded areas as necessary. Internal boards will be connected using Nanonics cables. Connections to the S/C will be via standard D Subminiature connectors Connections to external components (SIT and both SEPT’s) will be cabled using Micro-D (MDM) connectors.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR8 Main SEP Assembly Status Designs for Main SEP Electronics Box components are 75% complete. HV Bias Shields design is 80% complete. Internal bracket designs and cable harnessing runs are 50% complete. Drawings are 25% complete. Analysis is being performed on the box structure to assure stiffness for the LET bracket as well as internal components.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR9 Low Energy Telescope (LET) Schematic Top Cover M.I.S.C. Electronics Board Upper Shields L2 & L3 Detectors Inner Detector Housing Detector Collimators L1 Detectors Main Housing Lower Shields Front-End Electronics Bottom Covers

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR10 LET Telescope Bracket LET Telescope and Electronics SEP Box

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR11 LET Telescope & Bracket Status Telescope and enclosure designs are 85% complete. Drawings are 40% complete. Detector mounts have been fabricated and prototype detectors are being installed into the mounts. Bracket vibration analysis results TBD. Purge restrictor calculations will be performed upon completion of design Vibration and Acoustics tests will be performed on the bracket at the instrument assembly level.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR12 HET Telescope Schematic and Assembly Front Foil, 10 mil Kapton 500A VDG inside GSFC Comp. Coat and ITO outside Collimator H1 Detector Telescope Main Body H2 Detector H3A & H3B Detectors Telescope Bottom Cover H4A & H4B Detectors H5A & H5B Detectors H6 Detector

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR13 HET Telescope Status Telescope and enclosure designs are 80% complete. Drawings are 50% complete. Detector mounts have been fabricated and prototype detectors are being built. Purge: sintered metal restrictor at 15 PSI permits flow rate of 1 liter/hour (~1 volume replacement every 4 minutes)

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR14 HET Electronics Assembly Inside view of componentsOutside view of components Telescope HET/SEP Enclosure Front-end Electronics Board Telescope HET Enclosure

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR15 HET Electronics Enclosure Electronics enclosure is aluminum and makes up half of the top and two thirds of the side of the Main SEP Electronics Box. Provides a base for the Flex/ Rigid PCB assembly to be held in its flight configuration to limit working the flex area. Allows telescope to remain attached to electronics from early on through testing and final integration to the Main SEP Box without having to be separated.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR16 SEP Supplies (LVPS & Bias) Low Voltage Power Supply boards are being designed by UC Berkeley Housing is being designed at GSFC. Common Ground Shield Isolated Ground Shield PCB High Voltage Bias Supply board is being designed by Space Instruments. Shields are being designed at GSFC. Housing PCB’s

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR17 SEP Central Assembly SEP Central Enclosure Logic Board Analog/ Post- Regulator Board Houses common electronics for all telescopes

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR18 SEP Suite Purge 15 PSI dry nitrogen purge accepted from S/C through a ¼” teflon line into distribution manifold on main SEP box. Purge is then sent out via three 1/8” teflon lines to the HET, LET and SIT telescopes. Purge flow will be restricted by a sintered stainless steel plug at the inlet to each telescope in order to limit the flow per individual telescope needs.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR19 Typical Mounting Foot Showing Thermal Isolation Ultem bushing for thermal isolation from S/C deck, 18mm diameter X 19mm thick. SEP Box aluminum mounting foot, 5mm thick Ultem Bushing for thermal isolation 13mm diameter X 3mm thick Titanium washer for ¼-28 bolt S/C mounting bolt 1/4”-28 Titanium x 2.0” long (electrically isolated from SEP Structure)

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR20 Typical SEP Ground Strap Being designed at UC Berkeley Design Goal: Thermal resistivity to be < 1/5th of total allowed between instrument and spacecraft.

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR21 SEP Instrument Suites SEPT-E SIT SEP/ HET & LET SEPT-N/S AHEAD SPACECRAFT SIT SEP/ HET & LET SEPT-E SEPT-N/S IN SAME POSITION AS AHEAD S/C BEHIND SPACECRAFT

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR22 SEP Locations on the Ahead Spacecraft

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR23 SEP Locations on Behind Spacecraft

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR24 SEPT-E F.O.V. (Behind S/C) Impingement and Close-call Rear FOV 0.16” from Solar Panel Catch BracketRear FOV Impinged by SWAVES Antenna

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR25 SEPT-N/S Impingement (both S/C) FOV impingement with Solar Panels

STEREO IMPACT SEP Critical Design Review 2002-Nov-21/22 TvR26 LET Telescope FOV (Behind S/C) Impingement and Close-call 0.06” clearance Forward FOV impingement was accepted at PDR but has since been cleared Rear FOV Impingement with SWAVES Antenna