Spacecraft Interface and I&T EFI Instrument Spacecraft Interface and I&T Preliminary Design Review Bill Donakowski Mechanical Engineer University of California - Berkeley

Radial Booms (4X) Located Orthogonal to each other Spacecraft Interface Radial Booms (4X) Located Orthogonal to each other X-Y Plane Spin Companions (A/B & C/D) In-Line +/- 1 degree Opposing Units Perpendicular +/- 2 degrees Z Axis Boom Deploy Centerline w/i 2mm for all units on Probe Boom Deploy Centerlines w/i TBD to Probe CG Axial Booms (2X) Both Booms Built-Up Together at UCB Boom Assy Fits into Probe Opening Goal of Line-Of-Sight Access for Bolts Instl and Inspection as Possible

Interface to Probe Issues Axial Booms Careful Coordination required as Boom Tube is Primary Structure to Probe Installation and Removal Design and procedures in-work Probe Antenna part of Boom Testing of Antenna may be issue Installation of units need to be coordinated Radial Booms Probe Propellant Tanks/SPBs in close proximity Issue being worked by UCB/Swales Designers Shadowing of SPB Doors and Exit Tube on Solar Array TBD Deployed Spin Plane Booms and relationship to Probe Thruster Plume TBD Both Thrusters and Axial Boom Spin Plane in-line Thermal effects of plume on Wire TBD (not preferred)

EFI Instrument on Probe Axial Boom 4 x SPB Probe Mounting Deck

SPB on Spacecraft Probe Tank Plane of Exterior Solar Panel (Removed) SPB Release Doors Probe Deck Close Proximity to Tank (~.45”)

Axial Boom On S/C AXIAL BOOM INTEGRATION TO THEMIS PROBE Antennae Mount Axial Boom Composite Tube Upper Deck Mount Lower Deck Mount THEMIS PROBE WITH AXIAL BOOM AXIAL BOOM

Integration and Test Philosophy Environmental Test Instrument Subassys Individually Build up EFI Instrument on S/C Simulator Test/Check-Out/Compatibility Populate Qualified and Checked out Instruments onto Probe Perform minor electrical/continuity checks following Probe Integration Enable Plugs with connection break-outs at Subassys Safety as well as good check of End-to-End Rationale Various Components tested together to Best Select based on compatibility Untie Probe/Instrument Schedules as much as possible Limit Probe/Instrument Integration times Limit need to change out Instruments due to Problems

Pre-Integration Testing Overall Check-Out EFI Instrument completely Checked-Out Prior to arrival of Probe Continuity Check at Enable Plug Break-Out Able to send signal from IDPU to Break-Out Boxes Command Deploy Monitor Virtual Motor Verify Integrity of Sphere Surface

Post-Integration Testing Overall Check-Out Perform minor electrical/continuity checks following Probe Integration Send Signal to Enable Break-Out Boxes Verify Signal Send/Receive No Functional Checks of Full-Up Instrument Following Integration Deployment Motors not Powered No Operation of Doors No Operation of Pin Pullers

Integration to Probe Issues Axial Booms Access may be a problem Probe Antenna part of Boom Safety concern of Deployment on ground Radial Booms Maintenance and check-out of Sphere Surface late in the flow as possible