Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for November 1994) 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 Operations during the month were normal. The new computer equipment has been ordered and should be operational in the first quarter of 1995. This should provide a more reliable system and yield operational efficiencies. << Solar Activity >> Activity on the Sun decreased to a low level in November producing only a handful of minor flares. There was another in the recent series of long duration flares, but it was only classified as a C1 event in the GOES flare classification scheme. It lasted for nearly 16 hours starting at about 12:00 UT on 13 November 1994 coming from an unnumbered active region in the northern hemisphere near the center of the solar disk. The corona showed a slow and widespread decay in the size and intensity of the active regions on the Sun. For example, the group of five small regions visible at the end of last month has decayed into areas scattered plage in all but two places. Although the Sun has continued to evolve towards solar minimum the X-ray corona continues to produce a large number of small-scale eruptions in the form of X-ray bright point flares and high-velocity coronal jets that are usually too small to detect from nonimaging monitors. Every now and then the Sun produces a large-scale eruption. However, neither of these phenomena seem to be as frequent or as violent as they were earlier in the mission. Page 2 << Campaigns >> SXT made successful observations of the eclipse and made supporting observations for the MSSTA sounding rocket up to about an hour before the flight. A table error terminated our planned coverage during the flight. << Science >> Most of our effort at LSAL has been focused on final preparations of our presentations for next month's AGU meeting. Jim Lemen and Greg Slater composed a new video stressing the evolution of large-scale coronal structures in and around the coronal holes. We particularly focused on the times near the passage of Ulysses across the southern polar hole and the two SPARTAN flights. In order to interpret the offpointed images that SXT took during the SPARTAN flights we have started to take a series of calibration images corresponding to the off points so the data can be accurately corrected for scattered light. We have also received a fairly large number of requests for help to provide data for other AGU posters and talks. During a visit to GSFC Keith Strong met with members of both the SERTS and SPARTAN teams to discuss the analysis and interpretation of the data we have in common and the possibility of coordinating observations for the forthcoming northern polar passage of Ulysses. Marilyn Bruner and Keith Strong helped with the Critical Design Review of the GOES SXI instrument - they were invited to do so based on their experience of the construction and operation of SXT. << Publications>> The following list is an incomplete listing of work in progress on papers and presentations that include scientists that are supported by the NASA SXT contract. - Papers Published (0) - - Papers accepted (3) - "Comment on 'The Solar Flare Myth'" H. Hudson, B. Haisch, and K. Strong, in press, JGR, 1995 "Ly-alpha and White Light Observations of a CME during the SPARTAN 201-1 Mission" D. Hassler, L. Strachen, L. Gardner, J. Kohl, M. Guhathakurta, R. Fisher, and K. Strong, Proceeding of the 3rd SoHO workshop Page 3 "X-ray Bright point and High-speed Wind Streams: A preliminary Analysis from Yohkoh and Ulysses data" G. Poletto, S. Suess, J. Khan, Y. Uchida, E. Hiei, M. Neugebauer, B. Goldstien, K. Strong, and K. Harvey, Proceeding of the 3rd SoHO workshop - Papers submitted (1) - "Temperature Structure of the Solar Corona: Comparison of NIXT and Yohkoh X-ray Images", T. Yoshida, S. Tsuneta, L. Golub, K. Strong, and Y. Ogawara, PASJ, 1995 - Presentations (0) - - Abstracts submitted(0) - << Public Use of SXT Images >> We received a request for permission to use one of the SXT solar image sequences in an educational CD-ROM based on its "Cosmic Clips" video. Gary Linford and Keith Strong prepared another in the series of the monthly articles for Sky & Telescope. We supplied the eclipse photographs to British "Astronomy Now" science magasine for inclusion in their next issue << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function well with no Single Event Upsets (SEUs) although there were a couple of usual sort of SXT table upload problems. No significant degradation in the instrument has occurred since the loss of the front thermal shield in 1992. SXT experienced a single SEU event during the month: 27 November pass 1 Bit Map Error There was an SXT table error on 3 November. Page 4 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot ------------------------------------------------------------------------------ Thru Aug-92 66010 32475 210862 113526 324388 119221 26.40 Sep-92 6087 2916 26832 20042 46874 15729 25.12 Oct-92 6753 2552 51037 14709 65746 23529 26.36 Nov-92 6648 2949 24345 14832 39177 12859 24.71 Dec-92 6766 3008 24188 6600 30788 12454 28.80 Jan-93 6888 3351 24067 4861 28928 13069 31.12 Feb-93 6833 3004 24479 18149 42628 12302 22.40 Mar-93 7177 3460 25874 19537 45411 14657 24.40 Apr-93 7754 3644 34128 8352 42480 17967 29.72 May-93 8571 3950 41832 7518 49350 21971 30.81 Jun-93 7340 2589 64545 12539 77084 26299 25.44 Jul-93 8259 3650 47561 5352 52913 24213 31.39 Aug-93 7628 3638 30705 3563 34268 17436 33.72 Sep-93 6875 2899 22697 5600 28297 11252 28.45 Oct-93 7474 3657 33782 7548 41330 20104 32.72 Nov-93 8504 3864 42953 5849 48802 23896 32.87 Dec-93 5898 3047 21128 13297 34425 13001 27.41 Jan-94 6934 2804 28567 10960 39527 13746 25.80 Feb-94 7000 2840 23021 5819 28840 11257 28.07 Mar-94 7736 2627 69273 3733 73006 31464 30.12 Apr-94 6142 2741 22707 3390 26097 12338 32.10 May-94 7070 2679 25260 3040 28300 10862 27.74 Jun-94 7417 2738 36795 1996 38791 15760 28.89 Jul-94 7488 2941 50540 3275 53815 24153 30.98 Aug-94 7370 2337 35067 3993 39060 13485 25.66 Sep-94 7079 2552 25131 2855 27986 10677 27.62 Oct-94 7244 2497 25868 5884 31752 10319 24.53 Nov-94 5673 1664 22842 1469 24311 8055 24.89 Total 258618 113073 1116086 328288 1444374 562075 28.01 Number of Full Frame Images Received: 258618 Number of Observing Region Images Received: 1444374 Total: 1702992 Approximate Number of Shutter Moves/CCD Readouts: 2964986 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 (%) Sep-92 32.38 70.5 2062 954 -1.2 / 3 15.9 12.2 Oct-92 32.64 80.3 2317 1055 16.8 11.5 Nov-92 36.24 215.1 6112 1391 18.0 11.0 Dec-92 42.58 452.8 17390 2024 17.9 N/A Jan-93 42.59 453.1 13006 2034 23.8 / 2 19.2 N/A Feb-93 42.28 441.5 13895 2090 17.7 N/A Mar-93 43.14 473.8 14047 2151 17.7 N/A Apr-93 43.13 473.4 14304 2146 23.8 / 2 16.9 N/A May-93 43.45 485.3 16405 2357 17.3 N/A Jun-93 44.03 507.2 20037 2531 16.3 N/A Jul-93 44.52 525.6 23977 2700 22.5 / 2 17.7 N/A Aug-93 44.24 515.0 21879 2643 25.2 / 3 17.2 N/A Sep-93 45.07 546.2 27469 2745 17.5 N/A Oct-93 45.40 558.6 31684 2982 17.7 N/A Nov-93 45.33 555.8 32047 3210 23.8 / 3 19.7 N/A Dec-93 45.92 578.1 38515 3101 19.2 N/A Jan-94 46.18 587.9 42560 3464 22.5 / 2 20.3 N/A Feb-94 46.03 582.1 40449 3246 19.3 N/A Mar-94 45.92 578.0 39715 3420 18.2 N/A Apr-94 45.97 579.9 41302 3721 25.2 / 3 17.8 N/A May-94 46.25 590.3 45476 3557 18.3 N/A Jun-94 45.83 574.6 39340 3547 17.8 N/A Jul-94 46.76 609.5 53417 3990 18.2 N/A Aug-94 47.02 619.0 58434 4121 25.2 / 3 18.2 N/A Sep-94 47.07 620.9 58580 4028 18.3 N/A Oct-94 47.34 631.3 64974 4346 19.0 N/A Nov-94 47.54 638.6 68595 4626 20.5 N/A Dec-94 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-NOV-94 and 30-NOV-94 ACTON 27-NOV-94 30-NOV-94 * 4 (total of 4 days) ALEXANDER 1-NOV-94 * 5-NOV-94 5 (total of 5 days) BRUNER 1-NOV-94 26-NOV-94 26 (total of 26 days) FREELAND 22-NOV-94 30-NOV-94 * 9 (total of 9 days) HUDSON 1-NOV-94 * 30-NOV-94 * 30 (total of 30 days) LEMEN 1-NOV-94 * 1-NOV-94 1 (total of 1 days) LINFORD 1-NOV-94 * 17-NOV-94 17 (total of 17 days) NITTA 1-NOV-94 * 22-NOV-94 22 (total of 22 days) LEKA 7-NOV-94 30-NOV-94 * 24 (total of 24 days) ---------------------------------------------------------------- Grand Total of 138 days for 9 people NOTE: The "*" signifies travel that actually ends after 30-NOV-94 SXT Foreign Travel between 1-DEC-94 and 31-DEC-94 ACTON 1-DEC-94 * 22-DEC-94 22 (total of 22 days) FREELAND 1-DEC-94 * 22-DEC-94 22 (total of 22 days) HUDSON 1-DEC-94 * 22-DEC-94 22 31-DEC-94 31-DEC-94 * 1 (total of 23 days) NITTA 19-DEC-94 31-DEC-94 * 13 (total of 13 days) LEKA 1-DEC-94 * 2-DEC-94 2 (total of 2 days) ---------------------------------------------------------------- Grand Total of 82 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-DEC-94 Respectfully submitted, Keith T. Strong Frank Friedlaender Page 7 ------------------------------------------------------------------------------- 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 December 1994 November 1994 |------------------------------- | 6. PERFORMING ORG | CODE: O/91-30 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- K. T. Strong | 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/91-30 |11. CONTRACT OR GRANT NO. 3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 37334 -----------------------------------------------|------------------------------- 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 November 1994 |------------------------------- |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 | 7 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office