Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for September 1995) 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 We have requested a no-cost extension to the old contract. The new contract will start after mid-November. We have been requested by MSFC to arrange for the new contract to begin after the old contract has been completed. Arrangements are being made to accomplish this and to ensure a seamless transition from old to new contracts for all co-investigators. We are pleased to welcome Serge Savy to the SXT team. Serge is employed on the Yohkoh contract through ARC. He has completed his post-graduate studies at MSSL, having worked with Prof J. Leonard Cuhane and will finish his Ph.D. thesis soon. Serge took up residency at ISAS in late September and will occupy one of the three Lockheed-rented apartments. << Solar Activity >> Solar activity was moderate during the month of September. There were several active regions present, especially during the first part of the month. Some produced B-class and a few C-class flares. The X-ray bright points have become more discernible as the active region emission has decreased. Yohkoh will soon begin to study the new-cycle regions if the Big Bear predictions are correct. << Campaigns >> There were two major campaigns during September. The first was the SPARTAN 201-03 mission that was launched by the Shuttle on 8 September. Page 2 Yohkoh made supporting observations. It has been reported by the Goddard group that the White Light Coronagraph acquired an excellent set of images which show the north polar hole and streamers. The UVCS also is reported to have data. During 15-23 September, we used most visible orbits to run special sequences for the XBP campaign. Three areas were selected from the northern hemisphere, and each of them was tracked for a couple of days. The last area was selected so that we could observe both XBPs and a small filament to study their relationship. They are often identified with magnetic flux cancelation. Karen Harvey and Keith Strong requested that full-disk images with successively longer exposures be obtained to see if the number of perceptible XBPs changes. Based on a quick look at these images, there was not much difference in the number of counted XBPs for images of 30s and 85s exposures. << Science >> Dr Ronald Moore, NASA-MSFC, is spending a few months at ISAS on the visiting Professor program. He is concentrating on SXT observations of erupting filaments. It is pleasure to have Ron at ISAS for a long visit and to interact with him on a range of science topics. In early September (11-12) there was a workshop at ISAS to commemorate the retirement of Prof Hirayama. The meeting was divided into four sessions which touched on topics to which Prof Hirayama has made significant contributions: (1) faculae, (2) helium-line formation, chromospheric and coronal heating, as well as Solar-B science, 3) prominences, and 4) flares. Late in the month many Japanese scientists prepared for the annual autumn meeting of the Astronomical Meeting of Japan, which was held in early October in Niigata. SXT observations in early September resulted in an interesting discovery. A special observing sequence was created by Hirohisa Hara and Serge Koutchmy, with the help of Mark Weber and Hugh Hudson, to look at N polar plumes and transient spikes. A version of this table was developed for the SPARTAN 201-3 support observations, and the test data have now been reduced by Kevin Reardon. A special observation sequence was devised to observe faint jets in the northern polar region. There was an attempt to repeat this observation, but the diffuse coronal emission was too large. The result of this interesting observation was the detection of no less than four X-ray jets over a two-orbit period, three of which were so faint that they would not have been detected without a careful dark subtraction. Each of the jets was associated with a bright point, leading K. Shibata to the reasonable conclusion that ALL flaring bright Page 3 points will have jets associated with them. This observation may provide a link between the Yohkoh/SXT X-ray jets and the plumes studied at many wavelengths earlier. This has implications for coronal heating and the formation of the solar wind. Hugh Hudson continued to work on the 13-Nov-1994 eruptive event. It is believed that this is the first event for which the CME structure can actually be observed during its initial motions, and can be interpreted in terms of the Hirayama model of flux-rope eruption. Nariaki Nitta analyzed more limb flares to show eruptions, if ever, do not generally precede the impulsive phase. << Publications>> The publication list will be reported next month. << 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. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. The spacecraft attitude performance was recently reviewed at the weekly operations meeting for the past year. The pointing stability has not changed at all, indicating that there has been no degradation in the gyros or spacecraft attitude control system. There has been no further increase in the SXT straylight since 16-Aug-1995. 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 bitmap error Sep 02 Pass 1; 950902-0101 recovered in the same pass SXT filter soft error Sep 25 Pass 1; 950925-0927 recovered in Pass 2 Page 4 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jun-93 136827 63898 552189 240665 792854 290057 26.62 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 6569 1941 26243 1956 28199 9293 24.79 Dec-94 6429 2456 26763 2583 29346 11904 28.86 Jan-95 6870 2349 26103 1699 27802 10211 26.86 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 5080 2389 16798 1196 17994 8559 32.23 Oct-95 0 0 0 0 0 0 0.00 Total 325003 140150 1359380 352793 1712173 675293 28.28 Number of Full Frame Images Received: 325003 Number of Observing Region Images Received: 1712173 Total: 2037176 Approximate Number of Shutter Moves/CCD Readouts: 3575425 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 (%) Jul-93 44.46 523.4 23020 2600 22.5 / 2 17.7 N/A Aug-93 44.20 513.6 21319 2598 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 46.00 580.9 39074 3088 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 46.98 617.6 57624 4050 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 47.64 642.4 70877 4703 20.4 N/A Dec-94 47.82 649.1 74246 4917 21.5 N/A Jan-95 48.55 676.7 89758 5457 20.0 N/A 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 49.73 720.9 113815 7144 19.5 N/A Oct-95 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-SEP-95 and 30-SEP-95 FREELAND 18-SEP-95 30-SEP-95 * 13 (total of 13 days) HUDSON 1-SEP-95 * 30-SEP-95 30 (total of 30 days) LEMEN 30-SEP-95 30-SEP-95 * 1 (total of 1 days) NITTA 1-SEP-95 * 23-SEP-95 23 (total of 23 days) SAVY 27-SEP-95 30-SEP-95 * 4 (total of 4 days) SHING 28-SEP-95 30-SEP-95 * 3 (total of 3 days) SLATER 1-SEP-95 * 30-SEP-95 * 30 (total of 30 days) WEBER 1-SEP-95 * 23-SEP-95 23 (total of 23 days) ---------------------------------------------------------------- Grand Total of 127 days for 8 people NOTE: The "*" signifies travel that actually ends after 30-SEP-95 SXT Foreign Travel between 1-OCT-95 and 31-OCT-95 ACTON 28-OCT-95 31-OCT-95 * 4 (total of 4 days) FREELAND 1-OCT-95 * 2-OCT-95 2 (total of 2 days) HUDSON 11-OCT-95 31-OCT-95 * 21 (total of 21 days) LEMEN 1-OCT-95 * 30-OCT-95 30 (total of 30 days) LINFORD 19-OCT-95 31-OCT-95 * 13 (total of 13 days) SAVY 1-OCT-95 * 31-OCT-95 * 31 (total of 31 days) SHING 1-OCT-95 * 31-OCT-95 * 31 (total of 31 days) SLATER 1-OCT-95 * 2-OCT-95 2 (total of 2 days) MCTIERNAN 1-OCT-95 15-OCT-95 15 (total of 15 days) ---------------------------------------------------------------- Grand Total of 149 days for 9 people NOTE: The "*" signifies travel that actually ends after 31-OCT-95 Page 7 Respectfully submitted, James R. Lemen Frank M. 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 1995 September 1995 |------------------------------- | 6. PERFORMING ORG | CODE: O/91-30 -----------------------------------------------|------------------------------- 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/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 1995 |------------------------------- |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