Summary of MDI progress in 2001 and 2002 with examples of work planned for the coming few years. This page created March 2003

Notes from MDI for use in preparing senior review of SOHO operations, data processing, data analysis, and science investigations for FY04-05 with extension information for FY06-07.

I. Contents

 II. Previous Senior Review

The SOHO Prime Mission was from April 1996 through April 1998. The SOHO program was reviewed along with other operating missions in the NASA SEC Theme in June 1997. The result of that review was approval to continue SOHO operations and science analysis for what was called the SOHO Solar Maximum Science Program. The next review was the 2001 Senior Review. The MDI submission for the proposal development, the SOHO proposal, and the final report of the panel are linked on the following pages:

 III. MDI Science Contributions

MDI successfully provided observations leading to discoveries and progress in understanding of a number of topics during the SOHO prime mission and extended phases. MDI data has contributed to at least 14 PhD dissertations, made significant contribution to at least 15 symposia and workshops with proceedings, and provided data for at least 458 papers as of March 2003.

Since the 1999 Senior Review MDI contributed to several new discoveries. There is not space here to review them all so only a few are listed here. The full list of papers is linked below.

A number of MDI results have produced interesting visual results. Some of these are available in the MDI "Nice" Image Collection for use as needed by the MDI community.

 IV. Proposed Investigations

There are many science investigation topics presently proceeding with the support of MDI observations. The range of topics presently under investigation is similar to the topics in the hundreds of papers published to date. Some sample studies that require continued MDI observations in the declining and near minimum phases of the present cycle are described here.

The MDI science highlights and plans are in the attached document: 

as .pdf:

as .doc:

 V. MDI Instrument Status

After seven years of operation, MDI is basically working very well.

  • MDI has made about seventy million images. After on-board computations, it has delivered about eleven million raw data images to the ground.
  • There is an expected degradation in total light throughput likely due to changes in the front window. The reduction in transmission to March 2003 was about XXX% which corresponds to about XXX% per year. The throughput is plotted at The jumps in early 2001 and 2003 correspond to changes in the full disk exposure time from 150ms to 165ms and presently to 180ms.
  • In March 2000 the MDI shutter began to show a drop in exposure uniformity. The uniformity went from a part in 12000 to a part in 4000. For the 165 ms this corresponded to a jitter from one frame to the next of about 40 microseconds. The pre-launch specification was 40 microseconds. Since the prior senior review the shutter has not degraded further. In fact its performance improved when we reduced the optics package temperature. The plots at show the trends. In particular the shutter_quality.gif plot shows the uniformity. The shutter noise affects the helioseismology ONLY for degree l < 4 and adds noise to the zero level of the magnetic field. The magnetic field zero is corrected by analysis of the data (see Liu et al, 2002). If further degradation were to begin we can reduce the shutter usage with some loss of science opportunity. Since the shutter has not degraded below a part in 4000 we do not presently plan to change the observing sequence.
  • There is no detected change in the CCD flat field except for variations with focus change.
  • The drift in central wavelength of the Michelson's has nearly stopped.
  • The drift in best focus position has moved the nominal focus setting back almost to the design point. Shortly after launch it was at the limit of the adjustment range. This drift has also apparently stopped.

In summary, with the possible exception of the shutter jitter, there is no known limit to MDI's useful life within the SOHO expected fuel life.

 VI. MDI Data Processing

As of March 1, 2003 the MDI data processing system had archived 2.2 million datasets containing 118 Terabytes of raw and processed data. Of this 192 thousand datasets containing 12 Terabytes contain the calibrated level 1.5 science data and 79 thousand datasets totaling 24 Terabytes contain higher level science products. This data resides on 436 high-density tape cartridges. Additional copies of the level-0 data are maintained off-site.

The MDI data center has responded to 13579 individual online requests for data amounting to about 12.4 Terabytes. Data exports in the two years ending March 1, 2003 included 6610 requests totaling 6.764 Terabytes. Most requests are for multiple datasets. Requests for MDI data processed through the SOHO archives at GSFC and the remote SOHO archives in Europe are not shown here. Data export requests plots are shown at

 VII. MDI Publication Record

For Dissertations see: Dissertation List

For list of Proceedings see: Conference Proceedings List

For list of Papers see: Paper List

 VIII. MDI Education and Public Outreach Activities

Education and Public Outreach are important adjunct activities of the MDI team. These activities include:

  • Press releases when appropriate for new results. A mixture of local institution and NASA/ESA forums have been used. Since the prior Senior Review proposal these included:
  • Public lectures by several scientists at Stanford, Lockheed-Martin, and Guest-Investigator institutions. Lectures include local area astronomy clubs and local universities as well as public colloquia at our own institutions.
  • Development and maintenance of our public information web site at In particular we added daily updates for the present state of the Sun with links to current images.
  • Distribution of informative and educational posters including a constructible spectrometer. We completed fulfillment of requests made in the prior interval and instituted an online payment system to allow recovery of shipping and handling costs. We have distributed the posters via the web as well as at public events such as "Astronomy Day" exhibits and school site visits. In 2001 we mailed out 870 poster tubes (each tube contained 4 posters) to education institutions and 751 tubes to home schoolers, for a total of 1621 tubes in all. In 2002 we started charging for shipping on February 9. Up until then we sent out 226 tubes to schools and 139 tubes to home-schoolers. From Feb 9th onwards, we sent out 254 tubes to individuals bringing the total number of tubes to 619 for 2002. We also sent out 136 classroom packs of spectroscope posters (45 posters per pack) to schools. If we assume that each student gets a spectroscope poster from the classroom packs we sent out (45 students per pack) and based on the number of individual tubes of posters mailed, the spectroscopes and our material have reached about 8360 individuals in 2001 and 2002. If we include the 3 other posters sent out with the spectroscope posters in each tube, and the approximately 1000 posters at special events then we have distributed more than 16,000 posters in the two years.
  • Development and production of live webcasts in cooperation with the NASA's Learning Technologies Channel program at NASA Ames Research Center. In particular the Sun-Earth Day presentation in 2001 reached approx 10,000 people. The show for 2002 reached 100,000 since it was aired on NASA-TV.
  • Development and presentation of teacher workshops. These included for 2002 NSTA, 30 Teachers; NASA/SECAT at NASA-Ames, 50 teachers; SECAT at San Jose State U., 20 Teachers; NASA Hands on the Sun, Tucson, 40 Teachers; and University of Arkansas Science Day, 30 Students/Parents.
  • Support for local schools with classroom visits by astronomers with solar telescopes and spectral line emitting gas lamps. In 2002 these included for example: Oakland Native American Charter School - 30 Students; Branham High School, San Jose - 100 Students; Milpitas High School Career Day - 120 Students; University of Arkansas Science Day - 500 Students/Teachers/Parents; and Museum of Science & Tech, San Jose 200+ people. These visits include presentations, posters, and usually solar viewing.
  • Support of the "Project Astro" program by a number of members of the Stanford and Lockheed teams.