1. Instrument Overview Larry Springer HMI Program Manager

2. HMI Heritage HMI evolved from the MDI instrument on SOHO
SOHO was Launched in 1995
MDI is still providing excellent data after taking 75 million images
The HMI Mechanism designs are based on those used on MDI, TRACE, and other programs (C,D,F)
The HMI detectors are similar to the 4k x 2k CCDs developed by e2v and used on a previous program (D)
The HMI camera electronics is based on the camera electronics developed by RAL for a previous program (F)
The HMI structure is an evolution of the structure developed for a previous program (D)
The HMI electronics design is an evolution of the electronics designs used on MDI, TRACE, other programs (C,D)
The HMI Software is built on the software developed for previous programs (A,C,D,F)

3. HMI Instrument Components
The HMI Flight Instrument consists of the following components
The HMI Optics Package
The HMI Electronics Box
The HMI Intra Instrument Harness
The HMI Software

4. HMI Optics Package Subsystems
The HMI Optics Package Includes the following subsystems:
Optics
Filters
Mechanisms
CCD Cameras
Mechanical Structure
Thermal control
Image Stabilization
Split between Optics Package and Electronics Box

5. HMI Optics Package

6. HMI Electronics Box HMI Electronics Box
Mounted inside the SDO Spacecraft
Contains:
Power Converters
Control Computer
CCD Camera Interface and Data Compressor
Mechanism Controllers
ISS Electronics
Housekeeping
The Oven Controller and Limb Sensor Preamp are in the OP

7. HMI Reliability
HMI has the following features to enhance system reliability
Redundant Power Converters
Redundant Computer and Bridge Board
Cross strapping between Camera interface boards and Compressor boards allows one compressor to handle the full HMI data stream
Redundant mechanisms for wavelength tuning and polarization selector.
Multiple mechanism controllers boards designed with failure isolated in combination with redundant mechanisms controlled by different boards eliminate potential single point failures
Redundant Limb Tracker sensors
Redundant Filter Oven Thermal Control
The Reliability presentation will provide more detail

8. HMI Peer Reviews leading to PDR
September 17, 2003
Mechanisms
Optics Package Structure
October 8, 2003
Electronics
Flight Software
October 15, 2003
Optics Package Thermal
October 22, 2003
Optics
Filters
October 29, 2003
Telescope
Focal Plane Assembly
Reviews had LMSAL experts in each discipline as Peers
The SDO Project participated via Telecon connection
Review Minutes and Action Items are maintained on the HMI website
Action Items tracked to closure by HMI systems engineer
Action Items reviewed periodically at the HMI Team Meeting

9. HMI Summary Schedule

10. HMI Risk Management Plan
The HMI Risk Management Plan (2H00075) was provided to the SDO Project on 1 July 2003 as part of the HMI Concept Study Report
It was written to be compatible with the then current SDO Risk Management Plan
An updated SDO Risk Management Plan - (464-PLAN-003) was received on October 2003
The HMI Risk Management Plan will be updated to make it compatible with the revised SDO Risk Management Plan after Comments on the original plan are received.

11. HMI Risk Assessment
The large format high speed CCD Camera systems are a technical and schedule risk
Assessment: Moderate reducing to low after delivery of Evaluation CCDs
Mitigation: Excellent vendors started early in program to provide evaluation devices and developmental camera between the PDR and CDR.
Precision Michelson Interferometers key to science observation
Assessment: Low, MDI shows that it can be done
Mitigation: Excellent vendor (MDI & GONG experience) selected with early evaluation of the polarizing beam splitter (the heart of the Michelson) to reduce risk
Precision control of filter oven key to science observation
Assessment: Low, MDI shows it can be done
Mitigation: Early development of a brassboard oven & controller to demonstrate performance. Redundant oven controller to improve reliability
Hollow Core Motors and Shutters require 80 Million operation lifetime
Assessment: Low, Not a large step beyond reliability demonstrated on MDI
Mitigation: Life test to 160 Million operations with several samples, and redundant critical mechanisms