SPP FIELDS V5 Antenna Mechanical Peer Review

David Glaser, Paul Turin, Jeremy McCauley, John Bonnell, Dennis Seitz

SSL UCB7/17/13

Sep. 23, 2012 SPP FIELDS Meeting

• V5 Overview• Thermal• Antennas• Antenna to PCB• PCB• Housing• Mount to Mag Boom• Antenna FEA Analysis• Other TBDs

Agenda

V5 Overview

V5 is an electric fields antenna, mounted on the SPP FIELDS Mag Boom, that will provide 3rd axis measurements complementary to the V1-V4 data. It has only a single Preamp

Previous Design

~10 inches inboardOf SCM

V5 Overview

SC X-axis (RAM Direction)

Old Boom Design Shown Here

V5 Overview

V5 is an electric fields antenna, mounted on the SPP FIELDS Mag Boom, that will provide measurements complementary to the V1-V4 measurements. It has uses a single op amp to cover the LF+MF DC-1MHz frequency range

V5 Overview

Positronics DD15M0000G

Antennas

V5 PCB

Housing Cover

Housing

Mass: ~70 g

Key Issue: V5 Thermal

•Minimum expected temperature <<-100°C•Occasionally will see the Sun during SC slewing•Similar Preamps have been qualified for temperatures in this range•Temperature predicts need to be modeled• Including heat losses through harness

•Options for Thermal Control Being Considered:• Blanketing• Resistive heater on PCB with “clean” power source• Heater on exterior of housing• Low emissivity coating on housing

Antennas

9.73”

4.00”

AluminumAluminum

wall

PEEK Isolators

• What drives the antenna length?

• What surface finish for the antennas?

Antenna FEA Results 100G Quasi-static Load

Load Direction

Load Direction

100G Stress < 10 ksiFirst Mode Frequency: 493 Hz

Antenna to PCB Connection

A single photoetched BeCu part makes contact between the two antennas and the PCB

V5 PCB

Circuit Board Currently1.41” x 0.85”

Layout1.15” x 0.77”

Max Component Height with Headroom:Top 0.34” (8.6mm)Bottom 0.056” (1.4mm)

V5 Housing

• Housing and Cover are aluminum

• 0.10” wall thickness• PCB mounts to Cover with

4X #0-80 screws• Mounts to Mag Boom with

2X #4-40 Screws

1.71”

1.09”

1.07”

With Backshell

Glenair, 557T186

V5 PCB to DD15 Connector

Want to minimize housing size, but space is tight

V5 Mount to Mag Boom TBD

FEA Model For Antennas

Removed Holes from BoxRemoved Hex Nut (Interference)Fixed at Mounting Holes

Other TBDs

• Connector to PCB Wires/Connections• Harness• FEA with Connector & Backshell• Qualification Plan

Backup Slides

PCB Schematic

V5 PCB Mech. Drawing

PCB Layout

• Heater resistor is R9• Layout area could be reduced by

having an external heater• C1, C2 might be reduced or

eliminated, but that might lower bandwidth (TBD)

V5 SPF Interface