Introduction *

Agenda *

Situation report *

Systems engineering *

Subsystem reports *

Schedule *

Review of existing actions *

Actions arising at this meeting *

Any other business *

Date of next meeting *

These are the minutes of the EIS System Design Team meeting number 3 (SDT-x).

Held at the MSSL Ariel House, Thursday, July 1, 1999, 10pm.

Those present

Minutes prepared by MWT.

Reminder - documents referred to as EIS-xxx-xxx-xxx are available in the documents archive at the project website see http://www.msssl.ucl.ac.uk/solar-b/docs/doclist.html .

Followed the SDT General Agenda – EIS-meet-sdt-genda .

MWT reviewed the week's activities. Apart from the development of the subsystems, which will be covered later in this report, the most significant development was a request from the systems side to re-configure the structure with respect to its mounting points.

We discussed the Interface management both within and it outside of the EIS, as embodied in the ECIM series of documents (some examples having been prepared by George Simnett) and the Master Interface list (EIS-sys-des-mintlist). It was felt that it was better to have subsystem acronyms in use for the elements of the master interface list rather than a numerical scheme as at present. (Action MWT will propose a new scheme together with a draft configuration plan for the project)

It was felt to be important that MWT and HH establish good communications – primarily to discuss interface issues in some depth before raising them with the team. (Action MWT/HH coordinate more).

Following the System Hierarchy EIS-sys-des-hiearc - which needs updating (Action: MWT)

The problem of the structural design was reported by MWT. It seemed that see the latest iterations of the structure had not assumed any constraints of the absolute position whereas the launch fairing and the design of the spacecraft bus did in fact present some constraints. Saad will be able to address this problem in around a week's time. (Action: SMM)

Daniel Tye reported the beginning of a CCD radiator study. This is EIS action 87. There are three important aspect of the EIS thermal control. 1) will the CCDs be be adequately coolled by a passive radiator? 2) will there be adequate heater power to raise the CCD temperature for annealling purposes? 3) The thermal control philosophy of the structure as a whole. DPT’s study involves the first issue only. This will assume a reasonable range of orbits for Solar-B and attempt to derive an achieavable CCD temperature. It should be completed by the time of the next consortium engineering meeting (end July 99). Requirements on the thermal design of the EIS-ROE and EIS-MHC will also flow from this study.

Optical and mechanism progress will be reported in today’s NRL teleconference.

There is an urgent need to get more details of the TRACE shutter design for implementation at MSSL. (Action: MWT)

Camera. The nomenclature of the camera has been revised. It is now

Camera = Focal Plane Assembly + Readout Electronics

CAM = FPA + ROE

Both FPA and ROE fit inside the central box in the structure (STR).

CJM reported progress in the CCD development. Discussions with EEV had now included the option of a 1k (42-20) CCD. The affordability of this will depend on the cosmetic grade. There was a discussion of this. Column defects were felt to be the least acceptable. Chris will bring images taken in the presence of such defects to the next meeting. (Action: CJM). Chris will talk to XMM-RGS personnel about the cosmetic requirements of their CCDs. Need to present the arguments for having a 1K CCD based on the post-launch alignment budget. Matt will ask NRL to put something quantitative down. (Action MWT). There may be other solutions to this problem.

DGS warned of the risk of destroying devices if the right precautions weren’t follwed. XXM-OM programme had used up "quite a few". The dangers could come from static discharge or incorrect driver circuit design.

The ROE Breadboard programme was discussed. An option was to reproduce the Integral ROE (with non-flight parts). Another option was to wait for the Integral PFM to become available. It was felt that it was better to build one (first option) even though the designer (PDT) might not be available for testing. Chris/Duncan/Alec should learn quite a bit from the experience. (Action: MWT to discover more about the Integral schedule at MSSL).

Mechanism & Heater Controller MHC

Alec reported the initial planning of this subsystem. The functions of this unit may include the management of protection systems for critical mechanisms such as the clamshell, Door and launch lock. There was a discussion about such critical systems. Errors in mechanism actuation were often user-initiated. The EGSE and commanding software should guard against such possibilities. For example the door might require two commands to open it, and it would be made "illegal" to embed either command in a macro (thereby ensuring that a living human had authorised the command).

It was anticipated that the MHC will also monitor the temperature of motors and remove power if a motor temperature rose above a certain limit. This is to prevent outgassing from overheated motors from causing optics contamination.

The MHC will be part of the instrument thermal control system. A small microcontroller or other dedicated temperature control circuit could be incorporated, or the control function could be within ICU – this has not yet been decided.

If the MHC will be made outside MSSL then it will need to be specified quickly. (Action MWT/JLC to find out if this is the case).

Instrument Control Unit ICU.

Alec showed a few amendements to the Electrical Block Diagram.

Duncan and Alec had been working on the architecture of a system based around the ADSP processors. They had found that at least two commercial systems were available of a very similar nature. This is both encouraging (some others had been along this route) and a possible source of a ready-made ICU or ICU processor subsystem.

A Virtuoso RTOS (real-time operating system) and target board – with SHARC ADSP21062 processor had been installed in a PC. This is an evaluation copy and will have to be returned in 2-3 weeks. It has been supplied with a basic compiler/linker. It may be possible to run tests of HCOMPRESS code. There may be a problem in that no-one knows quite how to use it (Virtuoso) and the learning curve might be steep and bumpy. It’s possible that the sales reps/engineers might be helpful. (Action RAG to find someone to have a go if possible.)

The concept of a Compression Working Group was discussed. LKHM will soon be initiating this group. Action: Louise. It will

1. Develop better statements of EIS data output type and rate, based on reasonable assumptions about the EIS operating modes. A note by Ken Dere is available for discussion: Data Throughput Notes EIS-ops-desnote-datathru.

2. Determine the tradeoffs between compression rate (CR) and data quality. The latter will be measured by performing spectral fits on decompressed data.

3. List candidate compression schemes. In each case, what is the CR/quality trade? Proccessor speed requirement? Memory requirement? ADSP 21020 or 21060 systems may be assumed. It shouldn’t be assumed that the above development system will be available for code testing in the short term – code tests may have to be done on unix-boxes and results scaled somehow.

Onboard Software in general. Khalid will soon be able to provide required manpower estimates for scheduling and costing purposes.

EGSE. An equipment list had been drafted by RAG. This reflects discussions with MWT, CJM, AJM. This will be needed for planning. There was a very short discussion on EGSE topics. Action: MWT to ask the J-side if any ground-segment planning had occurred.

There wasn’t time to address this important issue!

Actions generated at consortium-level meetings are numbered. Check EIS-man-actions for details.

NB "-actions3" shows actions up to and including the March kick-off meeting. "-actions4" shows more recent actions. The earlier ones are necessarily appropriate any more. MWT intends, when time permits, to make a short statement about each action, even the old ones. The recent ones (A.67+) are being actively tracked.

These will be reported in the next minutes in this series.

MWT propose interface document scheme with memorable nomenclature

MWT draft configuration plan. Could take some time.

MWT, HH Greater coordination

MWT update system hierarchy etc with latest component names.

SMM consider mounting points (start 8 July)

DPT radiator study (A-87)

MWT get details of TRACE shutter design (A-80)

CJM demonstrate images w/ defects

MWT ask NRL for quantitative statement of post-launch misalignment risk.

MWT Integral schedule implications.

MWT/JLC will the MHC be contracted out?

RAG try Hcompress with DSP+virtuoso

LKHM kick-off Compression Working Group

MWT Any J-side ground-segment plans?

None.

Teleconference with NRL at 4pm Thursday, July 01, 1999.

Thursday, 8^th July, 99. 10 am MSSL library.