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This document discusses the challenges faced in the design phase of Solar-B.EIS.Sc3, including the unclear science goals, interface management, and schedule and costs. It also highlights the decisions made, progress achieved, and the need for further work on interfaces and planning.
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Solar-B EIS Steering Committee meeting 27th May 1999
The position last February • Design dichotomy • effort in UK slow or stalled • science goals not well articulated e.g. wavelength range choice • Interface management unclear • Schedule and costs unclear Solar-B EIS Sc3
Kick-off MeetingISAS, March 8-13 1999 • Mission Philosophy • Organisation • Master Schedule • Spacecraft Overview Solar-B EIS Sc3
Design of EIS • Cassegrain or OAP? • Technical drivers - feasibility, costphysical resourcesdisturbance torque- for: Structure, Optics, Detectors, Elec. • Line lists • Effective areas - useful lines in QS, AR, Fl. Solar-B EIS Sc3
Management Plan • Decision making • Science - PI’s + Project Scientist + Consortium • Program - PM (+MSP) + PI’s • Engineering - SDT • Decision dissemination • Science & Technical email lists (points of contact) Solar-B EIS Sc3
Design of EIS (2) • Value of Spatial Resolution • Value of Throughput • Decision-making panel ISAS, NAOJ, NASA, NRL, PPARC/MSSL • Throughput (OAP) given priority Solar-B EIS Sc3
… on from there • NRL asked to propose an OAP concept • … with two wavelength ranges170-206 Å250-290 Å • on the same detector, non-overlapped, if possible (implies two grating surfaces) • keep high throughput,improve spatial resolution if possible Solar-B EIS Sc3
The new NRL/GSFC designs • NRL/MSSL series of teleconferences- discuss progress and direction of optical design- also an opportunity to learn lessons from SOHO/LASCO • became clear that engineer-level round-table interaction needed Þ NRL opto-mechanical engineering meet. Solar-B EIS Sc3
preferred design “EIS-7T” • one of a series of optimisations • small grating - low risk • toroidal grating - more vendor choice • magnification - short spectrometer section • add telescope length - improve spatial resolution • details published by FTP 7 May 99 Solar-B EIS Sc3
Optical properties • Nyquist-limited - spot sizes closer to detector pixel size • effective detector pixels governed by “charge spreading” (R. Stern investigations) • large effective field-of-view - 1000 “ Solar-B EIS Sc3
UK response • BU - structural concepts • MSSL - camera head concepts • swift drawing interchange • mechanisms - mass? power? placement? Solar-B EIS Sc3
Opto-mechanical engineeringmeeting, NRL 17-18 May 99 • US, UK, J involvement • review NRL/GSFC work to date • approve the criteria and results • review subsystem technology & designsitems connected with main instrument • suggest ideal placement • iterate before BU consortium meeting Solar-B EIS Sc3
NRL/GSFC:- reduce lengthby 10 cm- issue new optical layout- denote volumes which must be separate ~ 1st June BU/MSSL- iterate structural concept, use sectional construction- include radiator placement- camera update ~ 14th June The main Actions Solar-B EIS Sc3
Interface Management • System engineering - an MSSL responsibility to lead, but need help/experience from team • Timetables (*) - e.g. mechanical & thermal models - aiming for Phase B !! • Interface list - (*) • Spacecraft Interfaces (*) Solar-B EIS Sc3
Panels - Meetings - Minutes • Consortium • Science • Oversight of technical progress • archive: EIS-meet-cons-YYMMmins -YYMMagen • System Design Team - includes NRL telecon • Technical • Sys Engineering, Budget, Schedule • EIS-meet-sdt-minutesX & EIS-meet-sdt-tcXXXX Solar-B EIS Sc3
The position now ... • Major design decision made • UK work going ahead • Science goals getting clearer • Wavelength ranges selected • Interfaces clearer - need more work • Planning (schedule /costs) - improving Solar-B EIS Sc3