Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for January 1998) OVERVIEW The YOHKOH Mission is a program of the Japanese Institute of Space and Astronautical Science (ISAS) with collaboration by the U. S. National Aeronautics and Space Administration and the U. K. Science and Engineering Research Council. The YOHKOH satellite was launched on 30 August 1991 from Kagoshima Space Center (KSC) in Japan. The purpose of this mission is to study high energy phenomena in solar flares and the Sun's corona. Under an international cooperative agreement, Lockheed, under NASA contract, is providing a scientific investigation using the Soft X-ray Telescope (SXT), one of the primary experiments of the mission. The SXT was developed at the Lockheed Palo Alto Research Laboratory in cooperation with the National Astronomical Observatory of Japan, and the Institute for Astronomy of the University of Tokyo. MAJOR PROGRAMMATIC ACTIVITIES IN THE MONTH The proposal for continued operations in Japan in 1998 is being prepared. It will embrace additional scientific tasks appropriate for the approaching solar max. << Solar Activity >> At the start of the month activity remained at a medium level, with about ten C flares and at least one M event. However, activity dropped significantly towards the middle of the month, with only one C-class flare (Jan. 5) in the interval. Solar activity returned from its low point later in the month with AR8131 and many C-class flares as well as one M event. On Jan 21 the south polar crown filament, complete with northward "V," erupted shortly after 04:00 UT this morning. Arcade formation was still on going at 07:00 UT, and a sizable, CME-like darkening appeared at the vertex (SE) of the V at 05:40 - 06:00 UT. At the end of January, the Solar activity was again low, with four C-class flares. The GOES background level hovered at C1-C2. << Campaigns >> During the week of 19-Jan-98 to 26-Jan-98 , we observed jointly with VLA and others, as organized by N. Gopalswamy. The target was the southern polar crown filament, which did in fact erupt (Jan. 21) but not while either the VLA or Yohkoh PFI's were observing Page 2 it. We did not cover the last day with PFI's or long exposures because of the telemetry holiday schedule. At the end of January, the major activity was preparation for the launch of the S520-CN rocket at January 31, 04:30 UT. A special jet observation was carried out for two orbits. The XDT rocket consists of an innovative normal-incidence X-ray telescope with complementary narrow passbands in the red and blue wings of an Fe XIV emission line. Its difference images will show the coronal velocity field in the line of sight, and in principle feature-tracking in its sum images will show the velocity field perpendicular to the line of sight. The rocket payload was designed and built by an NAOJ/ISAS group led by S. Tsuneta. From the SXT perspective, its success has been an important step scientifically and perhaps as a guide to SOLAR-B instrumentation development. << Science >> Acton worked on straylight correction problems. Preliminary tests indicate that very substantial improvements can be expected from this work and its implementation by Freeland and Metcalf. He also worked on adapting Kankelborgs ingenius streak-removal code to routine SXT image processing. Alexander worked on the analysis for the Whole Sun Month campaign. This included producing quiet corona radial temperature and density profiles, determining coronal hole boundaries with SXT data, temperature and density comparisons with CDS, and writing draft of paper for JGR special edition He also analyzed flare data for Brandon Schwartz of MIT for comparison with BATSE and GOES and analyzed AR7986 with Gary and Aschwanden to look at distribution of heating function along active region loops. Canfield worked with Sean Sandborgh and Alex Pevtsov on the chirality of large-scale structures in SXT images. He also worked on the November 15, 1991 preflare paper to effectively use an MPEG movie made by Kevin Reardon. Nitta re-analyzed the flares (35 in total) selected by Jakimiec et al., who discussed the coexistence of ~10 MK and ~20 MK plasma at the loop top source. He found that the displacement vector of the hard X-ray source relative to the soft X-ray source is in the direction of the apparent motion of the latter source, which is often considered to represent the field lines that have just reconnected. This is generally consistent with the reconnection hypothesis. << Public Use of SXT Images >> We are continuing to make Yohkoh/SXT images available for a variety of uses. Efforts continue to make selected images available on the Lockheed SXT WWW homepage (http://www.space.lockheed.com/SXT/). We receive requests for the Yohkoh posters (#2 and #3) by way of the form on the SXT homepage. Currently we receive requests via our homepage at the rate of 2 or 3 per day. The WEB access statistics in January were 72694 accesses and 2590 Mbytes transferred. Page 3 << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. We found that there had been another entrance filter opening early on 24 January 1998. This means we have lost 1/3 of the entrance filter. The level of straylight increased due to the new opening, but we have already taken the right leak images in thin Al and AlMg filters. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT FIL HD error 05-Jan-98 Pass 1: 980105-0204 recovered in the 2nd pass. SXT Bitmap error 07-Jan-98 Pass 2: 980107-0205 recovered in the same pass. SXT Shutter error 08-Jan-98 Pass 1: 980108-1548 recovered in the 2nd pass. SXT Bitmap error 26-Jan-98 Pass 1: 980126-1134 recovered in the same pass. Page 4 << Data Flow >> Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Oct-95 333406 144116 1386765 357203 1743968 690211 28.16 Nov-95 5745 2944 21252 517 21769 12119 35.76 Dec-95 6163 2615 24059 901 24960 11652 31.83 Jan-96 6474 2530 27015 1708 28723 14151 33.01 Feb-96 6200 2581 21380 890 22270 10773 32.60 Mar-96 6908 2869 25437 1460 26897 12274 31.33 Apr-96 7172 2124 45445 671 46116 18848 29.01 May-96 6925 2426 30272 1089 31361 12367 28.28 Jun-96 7515 2723 31952 1536 33488 14521 30.25 Jul-96 5954 1995 29886 4769 34655 12427 26.39 Aug-96 7214 3010 21187 1607 22794 9887 30.25 Sep-96 6904 2618 29906 303 30209 12663 29.54 Oct-96 7405 2853 16463 1842 18305 8034 30.50 Nov-96 7001 2296 24292 5395 29687 9340 23.93 Dec-96 7144 2643 25331 2087 27418 10412 27.52 Jan-97 7186 2747 21126 1257 22383 9915 30.70 Feb-97 6016 2034 22097 1072 23169 8961 27.89 Mar-97 7152 1300 26991 1209 28200 6394 18.48 Apr-97 6018 1055 23639 3890 27529 5349 16.27 May-97 7703 1455 29574 3783 33357 7121 17.59 Jun-97 7671 1557 25649 1396 27045 8045 22.93 Jul-97 8614 1385 32503 431 32934 6559 16.61 Aug-97 7316 987 23136 3519 26655 4990 15.77 Sep-97 7051 1479 33646 9596 43242 8887 17.05 Oct-97 7023 1134 26813 1827 28640 6043 17.42 Nov-97 6691 1376 26297 15306 41603 7131 14.63 Dec-97 5067 577 21607 1458 23065 3241 12.32 Jan-98 0 0 0 0 0 0 NaNQ Feb-98 0 0 0 0 0 0 NaNQ Total 511638 197429 2073720 426722 2500442 942315 27.37 Number of Full Frame Images Received: 511638 Number of Observing Region Images Received: 2500442 Total: 3012080 Approximate Number of Shutter Moves/CCD Readouts: 5249874 NOTES: * The loss of images is mainly due to BDR overwrites, but there are also occasional DSN dumps which are lost. * It is common to have observing regions which contain more than 64 lines, which requires multiple exposures to make a single observing region image. This is why the number of shutter moves is larger than the number of images received plus those lost. Page 5 << Engineering Summary Table >> Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) Nov-95 50.11 735.1 122163 7814 25.2 / 2 20.3 N/A Dec-95 50.19 737.9 123705 7927 22.6 N/A Jan-96 50.81 761.3 136197 8888 21.5 N/A Feb-96 50.67 755.8 133263 8705 22.5 / 2 21.5 N/A Mar-96 50.85 762.9 136982 8973 20.3 N/A Apr-96 51.14 773.6 142250 9500 19.9 N/A May-96 51.16 774.4 140697 10018 19.1 N/A Jun-96 51.56 789.2 147705 10634 20.7 N/A Jul-96 57.45 1010.2 146293 12228 19.8 N/A Aug-96 52.58 827.5 165676 12393 19.6 N/A Sep-96 52.47 823.3 162784 12350 20.0 N/A Oct-96 52.21 813.8 157689 12047 22.5 / 2 21.3 N/A Nov-96 52.45 822.9 161683 12534 21.9 N/A Dec-96 53.08 846.2 171224 13860 22.9 N/A Jan-97 52.35 818.9 164785 11354 23.8 / 7 23.3 N/A Feb-97 51.95 803.9 159426 10346 21.1 N/A Mar-97 55.99 955.6 158428 12190 21.2 N/A Apr-97 53.14 848.4 176207 13265 20.8 N/A May-97 52.96 841.7 172052 13094 20.7 N/A Jun-97 53.71 869.8 182715 14910 19.8 N/A Jul-97 54.44 897.3 184518 20173 22.5 / 2 21.1 N/A Aug-97 54.06 883.1 188485 15549 20.1 N/A Sep-97 54.77 909.7 196501 17757 21.0 N/A Oct-97 54.85 912.8 198157 17857 21.5 N/A Nov-97 55.17 924.8 202153 18993 22.5 / 2 23.1 N/A Dec-97 55.44 935.0 205598 19930 21.9 N/A Jan-98 N/A N/A N/A N/A 0.0 N/A Feb-98 N/A N/A N/A N/A 0.0 N/A NOTES: * The dark current calculations are using full half resolution 2.668 sec images not taken in during the SAA. The dark current rate assumes a "fat zero" of 30.5 DN and a gain of 100 e/DN. * The entrance filter failure of 13-Nov-92 eliminated the capability of taking optical images, so the optical transmission is not available after Nov-92. It also caused an increase in the dark current signal, however some of the increase shown here is an increase in the readout noise and is not a function of exposure duration. Page 6 << Personnel Travel >> SXT Foreign Travel between 1-JAN-98 and 31-JAN-98 ACTON 1-JAN-98 * 31-JAN-98 31 (total of 31 days) HUDSON 1-JAN-98 * 31-JAN-98 * 31 (total of 31 days) MCKENZIE 30-JAN-98 31-JAN-98 * 2 (total of 2 days) SAVY 1-JAN-98 * 31-JAN-98 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 95 days for 4 people NOTE: The "*" signifies travel that actually ends after 31-JAN-98 SXT Foreign Travel between 1-FEB-98 and 28-FEB-98 HUDSON 1-FEB-98 * 18-FEB-98 18 (total of 18 days) MCKENZIE 1-FEB-98 * 28-FEB-98 * 28 (total of 28 days) NITTA 1-FEB-98 8-FEB-98 8 (total of 8 days) SLATER 20-FEB-98 28-FEB-98 * 9 (total of 9 days) ---------------------------------------------------------------- Grand Total of 63 days for 4 people NOTE: The "*" signifies travel that actually ends after 28-FEB-98 Respectfully submitted, Thomas R. Metcalf Frank Friedlaender Page 7 6 ================================================================= Montana State Univ Activity Report for December 1997-January 1998 ================================================================= (R. C. Canfield) MSU ACTIVITY REPORT FOR OCTOBER/NOVEMBER 1997 INTRODUCTION The MSU group has carried out SXT operations, data analysis, graduate and undergraduate research, and public outreach, and has organized and participated in meetings. YOHKOH AND SXT OPERATIONS Weber spent most of December as SXT Chief Observer at ISAS. Acton traveled to ISAS at the end of December where he worked mostly on straylight correction problems. Preliminary tests indicate that very substantial improvements can be expected from this work and its implementation by Freeland and Metcalf. Canfield served two weeks as Yohkoh Duty Scientist for Mees Solar Observatory. RESEARCH AND EDUCATION Weber developed a simplified solar wind model in the MSU plasma physics course taught by Longcope. He also investigated a possible collaboration with Acton on long-term activity variations as observed by the SXT. Acton completed a paper "Physical Structure of a Coronal Streamer in the Closed Field Region Observed from UVCS/SOHO and SXT/Yohkoh" with Jing Li and John Raymond. McKenzie worked on a study with Suematsu on motions seen during a well-observed filament eruption. Canfield worked with undergraduate Sean Sandborgh and Pevtsov on large-scale structures in SXT images. Canfield started training undergraduate Jen Greenfield on the production of CD-ROMS for about 50 well-observed Yohkoh/Mees eruptive flares. He also worked on a manuscript about preflare phenomena in the November 15, 1991 flare to effectively use an MPEG movie made by Reardon. Papers Published: "Differential Rotation Rates in the Soft X-ray Solar Corona", M. Weber, D. Alexander, and L. W. Acton, Memorie S. A. It., vol. 68, 495, (1997). "Using the WWW to Make Yohkoh SXT Images Available to the Public", D. McKenzie, M. Larson, T. Slater, L.W. Acton, in "The Corona and Solar Wind Near Minimum Activity", Proceedings of the Fifth SOHO Workshop, O. Moe (Ed), (ESA SP 504), p. 561 (1997). Abstracts Published: Page 8 "Do You See What I See? A Lesson About Astronomical Imaging" M. B. Larson, D. E. McKenzie, T. F. Slater, AAPT Announcer, 27, 107 (1997). "An Emerging New Picture of the Active Sun" (Invited), D. E. McKenzie, AAPT Announcer, 27, 83 (1997). "A Proposed Agenda for Physics Education Research in Astronomy", T. Slater and J. Adams, AAPT Announcer, 27, 131 (1997). Talks Given: "Solar Irradiance and Telescope Design", L. W. Acton, ISAS Seminar (1997). OUTREACH and SERVICE: Acton approved the long-term SXT movie for the Yohkoh Public Outreach Program (YPOP). McKenzie, Slater and Larson traveled to New Orleans for the winter meeting of the American Association of Physics Teachers to publicize YPOP to hundreds of US physics teachers. McKenzie gave an invited talk in the "Frontiers in Astronomy" session, on solar activity and the current constellation of solar observatories. Larson gave a presentation of the "Filters" lesson in the YPOP Classroom. Slater presented Internet-based astronomy lessons (both YPOP and CERES). Several hundred "Changing Sun" posters were distributed. Canfield worked with Tim Slater and Loren Acton to improve public awareness of important SXT discoveries. He made initial contacts focussed on the Hudson, Sterling et al. discovery of the sigmoid - arcade pattern associated with halo CMEs. ============================================================= Univ of Hawaii Activity Report for December 1997-January 1998 ============================================================= (B. LaBonte) UNIVERSITY OF HAWAII ACTIVITY REPORT (B. LABONTE) Our activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition (including designated Yohkoh campaigns) at Mees, collaborative analysis of Yohkoh/Mees data, and preparation of manuscripts. Operational support for SXT was provided by Nitta at Mees and LaBonte in Manoa. Our colleagues Jiao and Mickey at Manoa, Canfield at Montana State University, Wuelser and Metcalf at Lockheed, and Hudson at Solar Physics Research Corporation aided in advice and oversight of Mees operations. Page 9 Weather during this interval has been normal for the season. The IVM was returned to full operation. The MCCD is in full use for the normal H-alpha imaging spectroscopy. All instruments are working well. ============================================================ Stanford Univ Activity Report for December 1997-January 1998 ============================================================ (M. Wheatland) Stanford Group Yohkoh Report for December and January 1998 Mike Wheatland has concluded his investigation, with Peter Sturrock and Jim Mctiernan (of Berkeley SSL) of the waiting-time distribution of flares observed by the ICE/ISEE-3 spacecraft. This old dataset was chosen because it has long stretches of data without gaps, and gaps strongly bias determinations of the waiting time. The derived distribution was compared with the distribution of a Poisson process, with a (time-varying) rate, the rate being estimated from the data. For this difficult step a new procedure - devised by Jeff Scargle and based on Bayesian statistics - was used. The observed distribution shows an overabundance of short waiting times (10 s - 10 min) by comparison with a Poisson process. At face value this result suggests the existence of sympathetic flaring, i.e. the triggering of one flare by another. However, it is also possible that the method of selection of flares in the ICE dataset has counted as distinct flares episodes of X-ray emission that are actually parts of a single flare. An unambiguous determination of the existence of sympathetic flaring may require the use of spatially resolved data, and so in a follow-up study, the Yohkoh catalogue of flares will be examined using similar methods. A paper has been prepared on results of the ICE/ISEE-3 study. Magnetic reconnection is widely considered to be the energy release mechanism underlying the phenomenon of solar flares. Attempts to apply the theoretical ideas of reconnection to flares have led to the magnetic charge topology (MCT) method, in which the magnetic fields in active regions, where flares occur, are approximated by buried monopole or dipole sources. This provides a simple representation of the field in the corona, and allows the topology of the coronal field to be calculated. Particular significance has been attributed to the locations of calculated separatrices (surfaces defining the boundaries between field lines connecting different pairs of sources), separators (the intersections of separators), and more recently, quasi-separatrix layers (regions where field-line linkage changes drastically). Correspondence has been reported between these structures and observed flare emissions. Mike Wheatland and Peter Sturrock have begun a study of the MCT method, to assess the merit of this approach. Topics of study will include whether the topology of the field can be determined on the basis of linear force-free (including potential) reconstructions, and whether the reported correspondences of flare emission and the intersections of separatrices with the photosphere depend on arbitrary groupings of the charge sources. Page 10 Peter Sturrock and Mike Wheatland are pursuing their study of the relationship between the coronal power budget and the photospheric magnetic field. In examining data compiled by Acton, they find a quite accurate quadratic dependence of the X-ray flux upon mean magnetic field strength. This data-set involves averages over the entire disk and over a Carrington rotation. As a next step in this investigation, we will be collaborating with Phil Scherrer and his colleagues in the SOHO MDI project. They will extract from their files daily histogram of magnetic-field intensity (by pixel) over a circular disk (e.g. of radius 0.2 R) at disk-center. We will then extract from Yohkoh data an integral of the X-ray emission over the same region, and we will seek the functional relationship between coronal power and photospheric field strength that yields the best fit to the data. We hope that, by pinning down more accurately the relationship between coronal heating and photospheric magnetic field strength, it will be possible to make more definite statements concerning current theories of coronal heating. =========================================================================== Solar Physics Research Corp. Activity Report for December 1997-January 1998 =========================================================================== (Karen L. Harvey and Hugh S. Hudson) KAREN L. HARVEY: Activities for December and January: (1) Using the coronal hole boundaries determined from the NSO/KP He I 10830 spectroheliograms and photospheric magnetograms, a study has been initiated to compare the He I 10830 hole boundaries with those determined in the Yohkoh/SXT full-disk images. The objective of this comparison is improve the boundary definitions used for the HeI 10830 images, particularly when the boundaries are uncertain and to understand the role of the re-alignment of the magnetic field in the formation of coronal holes as regions evolve. (2) Updated the Yohkoh bibliography from its last version compiled February 1997. Several entries require some additional information before being ready to submit for update in the /ys/gen/doc directory. (3) Preparation of NSO/KP full-disk magnetograms and He I 10830 spectro- heliograms for SXT investigators for studies of the magnetic field and He I 10830 structures associated with X-ray structures. Planned Activities for February and March: Activities for February and March will to continue the analysis of the data from the several XBP campaigns and writing of planned papers on X-Ray Bright Points; to continue the analysis of the history of the activity complex 7958/7978, the evolution of its fields and connections by comparing the magnetic field, He I 10830 and SXT observations, and the continuing Page 11 with the drafts of the next two papers planned on this work and concentrating on the analysis of the formation of coronal holes in this complex. Work will continue on comparison of the boundaries of coronal hole determined from the HeI 10830 spectroheliograms with those seen in the Yohkoh/SXT data and on updating the Yohkoh bibliography. Abstract submitted: Harvey, K. L. and Hudson, H. S., "Solar Activity and the Formation of Coronal Holes", submitted for the COSPAR session on Coronal Structure and Dynamics near Solar Activity Minimum, to be held in Nagoya, Japan, July 12-19, 1998. HUGH S. HUDSON Activities in December and January The GRL paper on Yohkoh observations of halo CME counterparts was accepted. The projected paper on the celebrated multi-thermal filament structure was not completed, as planned; we now plan to have initial estimates of physical parameters (temperature) comparing the cavity with the core and streamer structures if at all possible, and with Acton's presence at ISAS in January it seemed expedient to work on systematic errors in preparation for this. Analysis of the Nov. 6 X9 flare has proceeded, in conjunction with Sato of the HXT group. This flare was extraordinarily compact, and yet was involved (but how?) in the launching of a major CME. Because of the compactness, the density of the flare loops probably exceeded 10^12 in the initial phases of the event. Otherwise, little scientific work was done other than the items represented in the Web-based reporting system which has been developed since October. Refer to ftp://isass0.solar.isas.ac.jp/sxt_co/index.html for a listing of the items. This list also includes pages on the Nov. 9 flare. Plans for February and March With McKenzie at ISAS in February, we will work to complete the initial paper on multi-thermal filament structures. R. Schwenn of the LASCO team was contacted regarding EIT observations of this structure, and we hope to prepare some material for the COSPAR meeting in July. Otherwise the main effort will probably be organizational work for the April CDAW (please refer to http://www.solar.isas.ac.jp/CDAW3/ for details). If there is time before this meeting, Hudson would like to visit the TRACE operation assuming a successful launch. It would also be nice if some work on the Nov. 6 flare could be completed. Papers accepted Page 12 Hudson, H.S., Lemen, J.R., St. Cyr, O.C., Sterling, A.C., and Webb, D.F.: "X-ray coronal changes during halo CMEs", Geophys. Res. Let., accepted (1998). Watari, S., Watanabe, T., Acton, L. W., and Hudson, H. S.: "Limb Events Observed by Yohkoh and Coronal Mass Ejections: A Filamentary Soft X-Ray Structure on 5 October 1996", 5th SOHO workshop, Oslo June (1998). Galvin, A. B., and Hudson, H. S., "An Overview of IACG Campaign 4: Solar Sources of Heliospheric Structure Observed Out of the Ecliptic": ESLAB-97 (1998). Hudson, H. S., and Galvin, A. B., "Correlated Studies at Activity Maximum: The Sun and the Solar Wind": ESLAB-97 (1998) Bothmer, V., Posner, A., Kunow, H., M\"uller-Mellin, R., Delaboudiniere, J.-P., Thompson, B., Brueckner, G. E., Howard, R. A., Michels, D. J., Mann, G., Classen, H.-T., and Hudson, H. S., "Solar Energetic Particle Events and Coronal Mass Ejections: New Insights from SOHO": ESLAB-97 (1998). Svestka, Z., Farnik, F., and Hudson, H. S., "Post-Flare Loops Embedded in a Hot Coronal Fan-Like Structure": ESLAB-97 (1998). Simnett, G. M., and Hudson, H. S., "The Evolution of the Coronal Mass Ejection on February 23, 1997": ESLAB-97 (1998) Page 13 ------------------------------------------------------------------------------- NASA REPORT DOCUMENTATION PAGE (IN LIEU OF NASA FORM 1626) --------------------|--------------------------|------------------------------- 1. REPORT NO. | 2. GOVERNMENT | 3. RECIPIENT'S DR-01 | ACCESSION NO. | CATALOG NO. --------------------|--------------------------|------------------------------- 4. TITLE AND SUBTITLE | 5. REPORT DATE Monthly progress report - for the month of | 10 February 1998 January 1998 |------------------------------- | 6. PERFORMING ORG | CODE: O/H1-12 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- T. R. Metcalf | TION REPORT NO: F. M. Friedlaender | |------------------------------- -----------------------------------------------|10. WORK UNIT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS | Lockheed Palo Alto Research Labs B/252 |------------------------------- Solar & Astrophysics Laboratory O/H1-12 |11. CONTRACT OR GRANT NO. 3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 40801 -----------------------------------------------|------------------------------- 12. SPONSORING AGENCY NAME AND ADDRESS |13. TYPE OF REPORT AND Marshall Space Flight Center (Explorer Program)| PERIOD COVERED Huntsville Alabama 35812 | Progress report for the month | of January 1998 |------------------------------- |14. SPONSORING AGENCY | CODE MSFC / AP32 -----------------------------------------------|------------------------------- 15. SUPPLEMENTARY NOTES ------------------------------------------------------------------------------- 16. ABSTRACT The SOLAR-A Mission is a program of the Institute of Space and Astronautical Science (ISAS), the Japanese agency for scientific space activity. The SOLAR-A satellite was launched on August 30, 1991, to study high energy phenomena in solar flares. As an international cooperative agreement, Lockheed, under NASA contract, is providing a scientific investigation and has prepared the Soft X-ray Telescope (SXT), one of the two primary experiments of the mission. --------------------------------------|---------------------------------------- 17. KEY WORDS (SUGGESTED BY | 18. DISTRIBUTION STATEMENT AUTHOR(S)) Solar-A, X-ray, CCD, | Space Science, Solar Physics ------------------------|-------------|----------|-----------------|----------- 19. SECURITY CLASSIF. | 20. SECURITY CLASSIF. | 21. NO OF PAGES |22. PRICE (OF THIS REPORT) | (OF THIS PAGE) | | None | None | 13 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office