Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for December 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 Martin, 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 Martin Solar and Astrophysics 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 A proposal was submitted to MSFC for continued operations and additional SXT data analysis in CY1999 to supplement the very reduced data analysis allocation budgeted for 1999. This brings the level of support to almost the amount recommended by the Senior Review Panel. It is with great sadness that we lose John Owens to retirement. John has been involved with this program from its inception more than ten years ago. He has provided valuable counsel and encouragement through the definition, development, and operational phases based on his many years of experience, and thus played a significant role in the success of Yohkoh and the corresponding contributions to solar coronal physics. John will be sorely missed as his personal commitment to the program was evidenced by the fact that he was a very strong defender of the program when times were hard. Jim Lemen and Frank Friedlaender went to MSFC on December 15 to affect the transition of John Owens to Larry Hill as Manager of the SXT program. We welcome Larry Hill to this exciting program and are looking forward to working with him. << Solar Activity >> Solar activity dropped in early December, but many C-class flares occured in NOAA AR8395, AR8392, and AR8402. Yohkoh observed the start or gradual phase of many of these flares. Many bright loops were observed in AR8395 and AR8397 as PFI targets. There were no X-class flares, however, although the GOES background level remained fairly high. In mid-December, Solar activity was noticeably (but not greatly) higher, with several LDEs in the low- to mid-C range. The GOES background also rallied to C1 level. There were no M-class flares, however. Page 2 In late December, solar activity continued at a high background level, hovering near C1. We observed occasional C-class flares and four M-class flares. The M-3 flare at 7:45UT in December 17 was not observed due to S/C night. An M-8 flare that occurred 17:22UT in December 18 may be partially observed. These events had strikingly impulsive time profiles. The dominant active region, NOAA 8421, was followed jointly by Yohkoh and TRACE. Solar activity was relatively high during the last week of December, showing three GOES M-class events on Dec. 23, 24, and 25. The peak of the soft X-ray emission for all of the three events were successfully observed with Yohkoh. Two additional M-class flares were observed on Dec. 28 and 29. << Campaigns >> There were no formal coordinated campaign observations during the month, but SXT followed AR 8421 in conjunction with TRACE. A VLA/TRACE study did not fall within our visible window. We only heard about the VLA time third-hand, so we've initiated an effort to improve general coordination. << Science >> SXT has not succeeded very well in detecting Moreton waves (large-scale coronal shocks) in spite of the simple logic that compressional motion should result in adiabatic heating and detectability. Yet we know from meter-wave type II bursts that such waves do occur, and the EUV observations of SOHO/EIT show a plethora of waves. Jim Lemen has analyzed the reasons for this discrepancy, which we attribute (a) to poor SXT counting statistics in the quiet corona (expressed differently, the image dynamic range in soft X-rays is larger than in the EUV); and (b) to differences in temperature response between EIT and SXT; with its sharply tuned filter, EIT will show greater modulation than SXT, which has a broader temperature response. However, we may have finally found one in the SXT data! An SXT difference image at the onset of a flare on 1998 May 6 (450 Mm wide) shows an arc propagating rapidly to the north. The arc appears to start at some distance (> 100 Mm) from the flare core, and to accelerate outwards, reaching a projected velocity exceeding 1000 km/s. The fast ejection seen to the N in this event may be associated with a Moreton or Type-II-burst wave, or in some other way to a CME ejection. We can't say yet whether this is a true wave or something magnetic (loop or flux-rope) anchored to the photosphere, but we're working on it! See http://www.lmsal.com/YPOP/ProjectionRoom/Weekly/981225.html for more details. << 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 LMSAL SXT WWW homepage (http://www.lmsal.com/SXT/). We receive requests for the Yohkoh Page 3 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 December were 34442 accesses and 1964 Mbytes transferred. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT Bitmap error 03-December-98 Pass 1: 981203-0825 recovered in the same pass. SXT Bitmap error 17-December-98 Pass 4: 981217-0722 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-96 413983 175406 1711017 374496 2085513 839929 28.65 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 6806 1013 28472 2136 30608 5263 14.67 Jan-98 5715 1803 23479 3232 26711 9918 27.08 Feb-98 6606 1644 25257 3606 28863 8989 23.75 Mar-98 6043 2056 23029 10399 33428 10939 24.66 Apr-98 6537 1103 22656 8087 30743 6339 17.09 May-98 7569 1838 28292 19018 47310 9868 17.26 Jun-98 6463 1638 24990 5618 30608 9051 22.82 Jul-98 6810 1892 27046 7357 34403 9970 22.47 Aug-98 5823 1960 22978 14126 37104 11167 23.13 Sep-98 6776 1432 21814 11626 33440 7753 18.82 Oct-98 6573 1901 23520 5198 28718 9220 24.30 Nov-98 6442 1695 25124 26948 52072 9920 16.00 Dec-98 1158 310 4257 221 4478 1635 26.75 Jan-99 0 0 0 0 0 0 NaNQ Feb-99 0 0 0 0 0 0 NaNQ Total 585890 217139 2353025 542836 2895861 1049108 26.59 Number of Full Frame Images Received: 585890 Number of Observing Region Images Received: 2895861 Total: 3481751 Approximate Number of Shutter Moves/CCD Readouts: 6028638 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-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 55.51 937.6 206194 20219 21.9 N/A Jan-98 56.06 958.0 212189 22121 23.9 N/A Feb-98 55.94 953.7 209254 22122 23.8 / 2 22.6 N/A Mar-98 56.29 966.6 213519 23249 21.8 N/A Apr-98 56.44 972.1 214676 23890 20.8 N/A May-98 56.90 989.4 215651 26905 21.4 N/A Jun-98 57.11 997.5 216285 28223 20.1 N/A Jul-98 57.05 995.1 215628 27690 21.4 N/A Aug-98 57.36 1006.7 217355 29544 20.9 N/A Sep-98 57.43 1009.5 218520 29683 20.9 N/A Oct-98 57.59 1015.3 220504 30221 21.3 N/A Nov-98 58.17 1037.0 223755 34614 22.5 / 2 23.4 N/A Dec-98 57.38 1007.6 219804 28926 22.9 N/A Jan-99 N/A N/A N/A N/A 0.0 N/A Feb-99 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-DEC-98 and 31-DEC-98 HUDSON 1-DEC-98 * 31-DEC-98 * 31 (total of 31 days) NITTA 1-DEC-98 * 4-DEC-98 4 (total of 4 days) WEBER 1-DEC-98 * 23-DEC-98 23 (total of 23 days) ---------------------------------------------------------------- Grand Total of 58 days for 3 people NOTE: The "*" signifies travel that actually ends after 31-DEC-98 SXT Foreign Travel between 1-JAN-99 and 31-JAN-99 ACTON 30-JAN-99 31-JAN-99 * 2 (total of 2 days) HUDSON 1-JAN-99 * 8-JAN-99 8 17-JAN-99 31-JAN-99 * 15 (total of 23 days) MCKENZIE 4-JAN-99 31-JAN-99 * 28 (total of 28 days) ---------------------------------------------------------------- Grand Total of 53 days for 3 people NOTE: The "*" signifies travel that actually ends after 31-JAN-99 Respectfully submitted, Thomas R. Metcalf 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 January 1999 December 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 Martin Missiles and Space |------------------------------- Advanced Technology Center, O/H1-12, B/252 |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 Contact: Larry Hill | of December 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 | 7 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office