OverviewLPW/EUV Peer Review

April 25, 2011

Topics CoveredLPW• DFB Electronics Dave Andreatta• BEB Electronics Bryan Pyke• PreAmps / Booms Greg Delory• DFB/BEB Mechanical and Thermal David Norman/David Braun

Jenny Young

EUV• Optical design and analyses Frank Eparvier• Mechanical Overview and Test Heather Reed • Mechanical Design David Braun• Analyses Scott Tucker• Thermal Jenny Young• Electrical Dave Andreatta

Attendees• Mark Lankton - Chair• Bob Ergun• Greg Delory• Pete Withnell• Chris Belting• Frank Eparvier• Dave Meyer• Jim Westfall• Nicholas Jedrich• Darren O’Connor• Neil White• Laila Andersson• Bryan Pyke• Greg Temmer

• Stasia Habenicht• Robert Valentine• Mark Kien• David Braun• Andrew Jones• Will Thompson• Dan Prichard• Tom Woods• Dave Curtis• Steve Steg• Heather Passe• Vladimir Kmeta• Bill Vermeer• David Andreatta

RFA Overview

• PDR– All PDR RFAs are closed

• CDR Peer Review– 15 RFAs– 4 Recommendations– No formal submittals for closure as of today– Should be able to have 50% or more submitted for

closure by iCDR

RFA (1)

Submitted By Topic Statement of Concern/Recommended ActionAndrew Jones Venting Round

Thin-Foil FiltersThe maximum differential pressure across the thin-foil filters is 100mT. This can be an issue both druing ascent and during vacuum testing. It is important to have purge/air bypass for all foil filters to minimize pressure differential across the filters while also maintaining light tightness.

Steve Steg Axial Play in Bearings

A single radial bearing will allow the rotor to have axial motion. This motion will result in sliding contact at Neyoro-G end of travel stop. Sliding contact is susceptible to cold welding.

Pete Withnell Scattered Light Analysis for Pin Puller

Treating the pin puller as a lambersian source may not be worst case, as the surfaces may exhibit more specular properties.

Mark Lankton Fire TiNi Pin Puller A & B Sides Together?

Currently the spacecraft apparently fires both A&B sides of the TiNi actuator simultaneously. Is that permissible by the TiNi spec.? On previous missions we have fired A or B but not both at once.

Dave Curtis DFB Support Structure

Dave Curtis has identified that the presented support structure invades the Magnetometer's board space. The maximum component height is 0.440 inches per the MICD. Action: (David Braun) Coordinate DFB frame stiffener design. Investigate suport that fits within specified height limitations.

Mark Lankton Vespel Bushing Around Pin Puller Pin

The vespel bushing around the pin puller pin may not serve any real purpose, and it is one more possible cause of failure. Recommend just deleting the bushing.

RFA (2)

Submitted By Topic Statement of Concern/Recommended ActionDave Meyer PreAmp Foot

Print ReversedDuring DFB/BEB/Preamp testing, we found that the preamp temp diode was reversed.

Dave Meyer Zero Crossing Effect

Given the I-V curve of a sweep, the zero crossing value for the dynamic offset algorithm needs to be programmable. The issue being the flatness of the curve with I=4.

Chris Belting H-Bridge Protection From Cross-Conduction

Shoot thru protection easily available for H-Bridge driver - unceratin if that was problem observed at Berkeley

Chris Belting Phase Inversion Protection Circuit-Prone to VBE Breakdown

Page 4 : Phase Inversion Protection circuit prone to operating base-emitter junctions in breakdown due to leakage current when signal is high (>PIP + 2 VEB). Use of resistor discussed.

Jim Westfall Glint Free FOV Change

Update s/c ICD to show the updated glint free FOV per the most recent optical analysis. + 7.7

Darren O'Connor

Difference AMP CM Flitering

I suggest adding caps to diode A&B return (R307,R303) to achieve high freq. common mode rejection.

Jim Westfall Active Sounding Performance

Redesign the active sounding drive circuit so that it meets requirements for notch frequency (TBD) and drive amplitude (TBD). As part of the action item response determine the above TBDs and verify with science and EMC board.

RecommendationsChris Belting Parts Stress

Recommendations

Use power supply slew rate APL spreadsheet for tantalum capacitor derating

Chris Belting Derating Info on 3.3V

Derating info on 3.3V of RH1201-contact aloullet via Jim Roper @ AvNet.

Bob Ergun Filters to use 200 Ohm resistors

Use 200 Ohm /0.1 micro-farad Filter on EUV low frequency channels.

Andrew Jones

Clipping AXUV-100 Leads

If it is decided to clip the leads on an AXUV-100 be very careful to stabilize the lead above the point to be clipped as we have "popped" the wire bands by doing this before.