Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for September 1994) OVERVIEW 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 30 August 1991 from Kagoshima Space Center (KSC) in Japan, and renamed Yohkoh. The purpose of this mission is to study high energy phenomena in solar flares. 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 by Lockheed 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 Administratively it was a quiet month. The science team provided strong support and interacted on a continuing basis with both the Spartan and Ulysses projects.We are initiating the operational phase of the new Fiscal Year with the purchase of new computer equipment to further enhance our operations. << Solar Activity >> The Sun was more quiet this month than last, producing no major flares from the two large spot regions (NOAA AR7773 and AR7776) that crossed the disk early in the month. They did produce many small C flares. However a frustratingly small number of them were observed by SXT as they seemed to occur preferentially during Yohkoh night. There were also some large-scale eruptions near the east and west limbs but not of the scale or brightness of some of the ones seen earlier in the mission. The SXT data for the second part of the month will be useful primarily for the study of the evolution of coronal holes, quiet-Sun loops, and XBPs, especially as it was taken in conjunction with the southern polar passage of Ulysses and the flight of SPARTAN on the Shuttle. << Campaigns >> As mentioned above, the SXT team successfully supported the prelaunch planning of the SPARTAN flight in September. The SPARTAN mission lasted about 40 hours following a preset series of observations. The pointing Page 2 positions for these were chosen with the aid of daily SXT images that were piped daily to the SPARTAN team members for a month before launch. As far as can be seen so far the mission was a success (the SPARTAN data will not be processed for several weeks yet). The SXT made a series of joint observations of the Sun with SPARTAN, concentrating on deep exposures of the quiet Sun at the southern pole. A special thanks should go to Hugh Hudson, Marilyn Bruner, and the Yohkoh operations team in Japan for organizing and executing these plans. SXT continues to take deep exposures above the southern polar region to support the southern polar passage of Ulysses. We continue to compare large scale eruptions seen in the southern hemisphere with the times of interplanetary events seen by Ulysses. The next few months should be fascinating as Ulysses moves rapidly from the southern to the northern pole. << Science >> This has been a quiet month for us with many people away or temporarily diverted on to other projects. Much of our remaining time has been used to help field questions on SXT from potential Guest Scientists who were preparing proposals for Yohkoh funding that were due near the end of September. With the publication of the proceedings of the 2nd SoHO workshop (Elba, 1993) several SXT-related papers have appeared in the literature. However much of our effort has gone into preparing contributions and abstracts for the upcoming Fall Meeting of the AGU in San Francisco. Several of us have been producing the final drafts of our various COSPAR papers. Several members of the Yohkoh team are preparing to attend the CDAW meeting in at the University of Hawaii, organized by Dick Canfield. << Papers and Conferences Proceedings>> The following list is not necessarily a complete listing of publications that used the SXT data over the last month. - Papers Published (4) - "Observations of Loops and Prominences," K.T. Strong, Space Science Reviews 70, 133, 1994 "Jets and Brightenings Generated by Energy Deposition in the Middle and Upper Solar Chromosphere," A. C, Sterling, K. Shibata, and J.T. Mariska, Space Science Page 3 Reviews 70, 77, 1994 "Structure and Development of Quiet Loops in the Solar Corona," E. Hiei, Space Science Reviews 70, 189, 1994 "Soft X-ray Observations of Helmet Structures from SXT," C.-C. Cheng, Space Science Reviews 70, 273, 1994 - Papers accepted (0) - - Papers submitted (1) - "Coherent Brightness Variations in Solar Radiative Output from the Photosphere to the Corona," J.L. Lean, J.T. Mariska, K.T. Strong, H.S. Hudson, L.W. Acton, H. Hara, G. J. Rottman, T. N. Woods, and R.C. Willson, to be submitted to Geophysical Research Letters, 1994. - Presentations (0) - - Abstracts (5) - "Yohkoh SXT Observations of the Solar Polar Region," J. Lemen, Fall AGU "Observations of Polar X-ray Bright Points by Yohkoh SXT," N. Nitta, Fall AGU "The Structure of the Solar Wind Speed Near the Sun Inferred from a Comparison of Radio Scintillation and Yohkoh Soft X-ray Observations" Klinglesmith et al., Fall AGU "Yohkoh Observations of Polar Rays," K. Strong et al. "Yohkoh Observations in Support of the SPARTAN 201 Mission - Plans and First Results," M. Bruner & H. Hudson, Fall AGU << Public Use of SXT Images >> Gary Linford and Keith Strong prepared another in the series of the monthly articles for Sky & Telescope. A request was received from Dr. K. Dow of the Harvard-Smithsonian Center for Astrophysics who is putting together a public outreach/educational science project that will include putting spectacular astrophysical images on posters on public transport systems to heighten public awareness of science. She contacted Keith Strong for permission to use some Yohkoh images as part of this programme. He was also interviewed (via a long transatlantic phone call!) by a British journalist who is Page 4 writing an article on the Sun and wanted to know about the recent discoveries from Yohkoh. We sent him a package of our standard PR images and videos. Yohkoh images were also used to publicize the Lockheed's R&DD Expo'94. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function well with a normal level of Single Event Upsets (SEUs). No significant degradation in the instrument has occurred since the loss of the front thermal shield in 1992. The SEU problems suffered by SXT in September 1994 are as follows: 9-Sep-94 Pass_2 : Bit Map Error -> recovered in same pass 12-Sep-94 Pass_1 : NGT_CM Error -> recovered in Pass_2 21-Sep-94 Pass 3 : FLT ST Error -> recovered in same pass 21-Sep-94 Pass 4 : BIT MAP Error -> recovered in same pass Page 5 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jun-92 52903 26412 162033 90891 252924 92606 26.25 Jul-92 6535 3085 24622 11481 36103 13065 26.57 Aug-92 6572 2978 24207 11154 35361 13550 27.70 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 2439 853 8652 1146 9798 3661 27.20 Total 241061 107213 1050897 319226 1370123 536685 28.15 Number of Full Frame Images Received: 241061 Number of Observing Region Images Received: 1370123 Total: 1611184 Approximate Number of Shutter Moves/CCD Readouts: 2803347 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 6 << 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 (%) Jul-92 32.19 63.2 1829 822 15.5 14.1 Aug-92 32.21 64.1 1922 886 14.9 13.1 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 46.94 616.2 56399 3895 17.6 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 7 << Personnel Travel >> --- SXT travel for the month of September 1994 --- SXT Foreign Travel between 1-SEP-94 and 30-SEP-94 List was Generated: 1-Oct-1994 16:05:51.00 PR_TRAV_SUMM Ver 1.0 29-Apr-92 BRUNER 1-SEP-94 * 20-SEP-94 20 (total of 20 days) FREELAND 7-SEP-94 30-SEP-94 * 24 (total of 24 days) HUDSON 1-SEP-94 * 16-SEP-94 16 26-SEP-94 30-SEP-94 * 5 (total of 21 days) LEMEN 26-SEP-94 30-SEP-94 * 5 (total of 5 days) WUELSER 1-SEP-94 * 26-SEP-94 26 (total of 26 days) ---------------------------------------------------------------- Grand Total of 96 days for 5 people NOTE: The "*" signifies travel that actually ends after 30-SEP-94 --- Planned SXT travel for the month of October 1994 --- SXT Foreign Travel between 1-OCT-94 and 31-OCT-94 List was Generated: 1-Oct-1994 16:06:24.00 PR_TRAV_SUMM Ver 1.0 29-Apr-92 ALEXANDER 2-OCT-94 31-OCT-94 * 30 (total of 30 days) FREELAND 1-OCT-94 * 7-OCT-94 7 (total of 7 days) HUDSON 1-OCT-94 * 14-OCT-94 14 24-OCT-94 31-OCT-94 * 8 (total of 22 days) LEMEN 1-OCT-94 * 31-OCT-94 31 (total of 31 days) LINFORD 18-OCT-94 31-OCT-94 * 14 (total of 14 days) NITTA 23-OCT-94 31-OCT-94 * 9 (total of 9 days) ---------------------------------------------------------------- Grand Total of 113 days for 6 people NOTE: The "*" signifies travel that actually ends after 31-OCT-94 =========================================================================================== Respectfully submitted, Keith T. Strong Frank Friedlaender Page 8 ------------------------------------------------------------------------------- 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 October 1994 September 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 September 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 | 8 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office