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.
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
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: http://soi.stanford.edu/results/2003_MDI_sr_review/mdi_sr2003_1.pdf
as .doc: http://soi.stanford.edu/results/2003_MDI_sr_review/mdi_sr2003_1.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 http://soi.stanford.edu/results/2003_MDI_sr_review/fd_ice_central_mean.gif
The jumps in early 2001 and 2003 correspond to
changes in the full disk exposure time from 150ms to 165ms and presently
- 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
http://mdisas.nascom.nasa.gov/shutter 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 http://soi.stanford.edu/production/cumulative.html
VII. MDI Publication Record
For Dissertations see: Dissertation List
For list of Proceedings see: Conference Proceedings List
For list of Papers see: Paper
VIII. MDI Education and Public Outreach
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
- 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 http://solar-center.stanford.edu.
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
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