Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for April 1997) 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 Considerable effort was spent writing the proposal for the Senior Review. It is clear that this is a necessary activity due to the current funding restrictions, but it nevertheless distracts from the main activities of the science mission. << Solar Activity >> Activity has been low for the most part during the past month. Solar activity picked up during the week of 12-19 April, when a hot, but short-lived new-cycle AR in the appeared in the south. Two C-class flares caused Yohkoh flare-mode flags on 15 April. These flares were from two new-cycle regions, and the new-cycle regions seem to be dominating the activity now. The general pattern seems to be that they begin hot, but die out quickly. A remarkable phenomenon occurred at the boundary of the N polar hole on 10-11 April. Possibly this was just a peculiar "restructuring" as a part of the normal helmet-streamer evolution, but it sure looked different. Fans of boundary behavior in coronal holes, and there are many such scholars around the world, might want to take a special look at this. << Campaigns >> At the end of April, a two-day joint observation with CDS was conducted on a weak active region near the SW limb and with a disk-center filament. The Page 2 orbit of Yohkoh was favorable for us to load an ARS1 table on pass 2 each day, then an ARS0 table on pass 4 to follow the CDS region. For Yohkoh operations, there is a text file accessible on the Web at http://www.space.lockheed.com/SXT/html2/First_Light.html which also lists the current SXT Chief Observer, or the Unix command: # finger campaign@isass0.solar.isas.ac.jp | more The SOHO target planning is available from: http://sohowww.nascom.nasa.gov/operations/targets/today << Science >> David Alexander spent part of the month at ISAS and was the SSOC Tohban one week and the SXT CO the next. He worked on off-the-limb synoptic maps of the SXT data for use in the Whole Sun Month project. He also presented the results of the non-thermal broadening study at the ISAS/Yohkoh seminar in a talk entitled "Turbulent Times". He is working Allen Gary at MSFC on 3D image rendering of active regions using SXT and EIT. Finally, he revamped the non-thermal line broadening paper which has been refereed (favorably), and discussed other BCS projects with Joe Khan. Tom Metcalf and David Alexander both worked some on the YPOP homepages. These are designed to be used for public outreach and education outreach. The site is beginning to come together very well. Tom resubmitted the Masuda event paper with David Alexander. They have heard back from one of the referees, but not the other, and are optimistic that the paper will soon be accepted. Tom began work on the SXT Pixon loop identification software that he and Alexander will present at the SPD meeting. They also plan to present a comparison of the MEM and Pixon reconstructions for HXT yet. Nariaki Nitta re-started the study of superhot flares in preparation for the Bozeman meeting and the Yoyogi proceedings. He would like to include the analysis of BCS Fe XXVI data. Nariaki also spent some time translating the Solar-B proposal from Japanese to English in preparation for the Solar-B meeting that was held in Japan in early May. Greg Slater has greatly improved in the tape copy system at Lockheed Martin, which has enabled us to catch up on a back log that was caused by unreliable 8-mm tape drives. There are plans to distribute archive data to the Co-Is on CD-ROM in the near future. << 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 April were 64552 accesses and 2092 Mbytes transferred. This is down 15% from March, which included a larger than access rate because of the interest in the CMEs that were reported in the media. On average, the growth rate Page 3 is about 8 to 10% per month. In addition, the Yohkoh/SXT homepage was mentioned on the NextStep television program on 2 May 1997. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. There has been no further increase in stray light since 25 August 1996. The quiet patrol image has been changed to Al/Mg (DPE=17) to try to improve the performance of the active region selection algorithm for times when the Sun is very quiet. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT SEU error 7-Apr-97 Pass 5: 970407-1238 recovered in Pass 1 on 8-Apr-97 (-0825) SXT SEU error 11-Apr-97 Pass 5: 970411-1134 recovered in pass 1 on 9-Apr-97 (-0721) SXT bit map error 28-Apr-97 Pass ?: 970428-0207 recovered in the same pass. SXT continues to perform well technically. During his recent trip to ISAS, Loren Acton completed the analysis of the extended UV flood experiment aimed at understanding the behavior of the "dark pixels" seen near the limb. A further experiment will be done in mid-May. Our understanding of the terminator images continues to improve with time. The spacecraft was re-pointed recently and this resulted in a new series of terminator images via the automated system. The Yohkoh pointing errors are extremely regular and we feel that we can sharpen up the re-pointing program to get a still tighter pointing distribution. This is valuable because of the pointing dependence of the stray-light pattern - our goal is to return the thin Al images to 1992 levels of perfection via stray-light compensation. The system is so solid now that this seems almost feasible. Page 4 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jan-95 272813 118155 1172353 333057 1505410 585428 27.67 Feb-95 6556 2545 23635 3825 27460 10111 26.91 Mar-95 5915 2082 21485 3448 24933 8485 25.39 Apr-95 6244 2266 22946 4493 27439 9688 26.09 May-95 7084 2884 29617 2647 32264 15331 32.21 Jun-95 7210 3087 25251 307 25558 12045 32.03 Jul-95 6418 4145 21180 1639 22819 15109 39.84 Aug-95 7683 2597 26115 2181 28296 10537 27.13 Sep-95 6546 2853 22006 1753 23759 10433 30.51 Oct-95 6937 3502 22177 3853 26030 13044 33.38 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 7522 2716 31984 1536 33520 14489 30.18 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 3655 595 14422 2319 16741 3399 16.88 May-97 0 0 0 0 0 0 0.00 Total 452146 187012 1845310 387835 2233145 888316 28.46 Number of Full Frame Images Received: 452146 Number of Observing Region Images Received: 2233145 Total: 2685291 Approximate Number of Shutter Moves/CCD Readouts: 4707986 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 (%) Feb-95 48.70 682.1 92457 5781 25.2 / 3 20.5 N/A Mar-95 48.35 668.9 85527 5271 19.4 N/A Apr-95 48.72 682.8 93904 5627 19.1 N/A May-95 48.73 683.4 94000 5820 18.8 N/A Jun-95 49.08 696.3 100780 6281 19.6 N/A Jul-95 49.34 706.2 106408 6628 18.1 N/A Aug-95 49.72 720.4 114414 7101 19.5 N/A Sep-95 49.79 723.1 115165 7222 19.6 N/A Oct-95 50.29 741.9 126452 7911 20.2 N/A 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 53.41 858.7 180587 13826 21.0 N/A May-97 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-MAR-97 and 31-MAR-97 ACTON 13-MAR-97 22-MAR-97 10 28-MAR-97 31-MAR-97 * 4 (total of 14 days) HUDSON 25-MAR-97 31-MAR-97 7 (total of 7 days) LEMEN 1-MAR-97 * 14-MAR-97 14 (total of 14 days) METCALF 1-MAR-97 * 7-MAR-97 7 (total of 7 days) SAVY 1-MAR-97 * 31-MAR-97 * 31 (total of 31 days) ---------------------------------------------------------------- Grand Total of 73 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-MAR-97 SXT Foreign Travel between 1-APR-97 and 30-APR-97 ACTON 1-APR-97 * 12-APR-97 12 (total of 12 days) ALEXANDER 2-APR-97 30-APR-97 * 29 (total of 29 days) HUDSON 11-APR-97 30-APR-97 * 20 (total of 20 days) SAVY 1-APR-97 * 18-APR-97 18 (total of 18 days) ---------------------------------------------------------------- Grand Total of 79 days for 4 people NOTE: The "*" signifies travel that actually ends after 30-APR-97 Respectfully submitted, James R. Lemen Frank M. 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 May 1997 April 1997 |------------------------------- | 6. PERFORMING ORG | CODE: O/H1-12 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- J. R. Lemen | 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 April 1997 |------------------------------- |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