Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for the month of September, 1993) 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 August 30, 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 ACTIVITIES IN THE MONTH << Solar Activity and Observation Planning >> The solar activity of early September remained very low, typically at mid-B GOES level. Because of the level of the X-ray activity, plans were made for another bright point observing campaign. For the week of Sep 12-19 the Solar activity remained at a high A Goes level. One C flare occurred on 16 Sep, however it occurred during spacecraft night. After many weeks of low solar activity, the GOES level finally increased at the end of September with the appearance of AR 7590. The region produced one M flare and numerous high-C flares. A typhoon which hit southern Japan has resulted in absolutely no Yohkoh data from 4-Sep to 7-Sep-93. Typhoon 13 rolled through Kagoshima and causing nearly 40 deaths and much general destruction. An interruption in electricity at KSC stopped Yohkoh operations on 4-5 Sept. When power was restored, it was discovered that the 20m antenna locking pin was bent, and the antenna could not be operated. Mitsubishi sent workers to sort out the problem and operations were restored after five days. The Yohkoh spacecraft suffered no problems, although, there will be a five-day gap in the long-term SXT movie. << Campaigns >> Between 23-30 Sept, SXT conducted a joint observing campaign with Norikura Observatory. Hirohisa Hara went to Norikura to assist in the observations while Toshifumi Shimizu acted as the SXT chief observer. The weather was generally poor, but there were two good days of observations. Norikura made observations in Fe X, Fe XIV and Ca XV lines (the standard red, green and yellow lines) of AR 7590 region while it was on the East limb. The principal purpose of this Campaign is to estimate the differential emission measure of the solar corona using SXT and coronal-line observations. Page 2 << Data Analysis Software >> Various pieces of software are being written to enable the coalignment and display of ground based data with SXT data. The task is relatively easy when working with full frame images, but becomes more involved when coaligning partial frame images. These routines will be verified and integrated and then released for general use. Jim Lemen contributed some time to the BCS spectral synthesis and fitting software. There is still a lot to be done, but it should soon be easy for a non-expert BCS user to display BCS spectra and even estimate temperature and emission measure in the 1-component case (i.e., no blue wing). The temperature and emission measure software is maturing and Gary Linford has written a simple user interface to calculate the temperature and EM. One of the IDL procedure allows the user to get quick estimates of time-profiles of the average Te, EM, and normalized light curves for either very small or large areas of an image. Synoptic maps of the SXT data are available for the whole mission. Further advances and refinements on the generation of these maps is being handled by Greg Slater. Jean-Pierre Wuelser modified the SXT image registration software to use the skew gyro data since it is being used since 20-Sep-93 (see note below on "Spacecraft Operations and Health") An update to the Yohkoh Software and Database User's Guide is being made and should be released by the end of October. << Instrument Operations and Health >> There were SXT Bit Map Errors on the following days (with a full recovery during the same pass or the next pass): BIT MAP ERROR occurred at pass1 on Sep 14. BIT MAP ERROR occurred at pass4 on Sep 23. BIT MAP ERROR occurred at pass1 on Sep 29. The 8' east/west offset pointing was done 8-Sep, 15-Sep, 22-Sep and 29-Sep. Sam Freeland wrote some ground support software to automatically monitor the SXT Active Region tracking accuracy and stability. This was required when solar activity dropped to a low level (early September) and the automatic region selection often mispointed, usually associated with SAA orbits. Although solar activity has since risen to a level where mispoints are infrequent, this monitor software is run daily by the SXT Chief Observer and will give an early indication of AR selection problems and provide feedback during future parameter (patrol image) optimization efforts. Page 3 << Spacecraft Operations and Health >> The Y-gyro drift rate has been increasing since March 1993. The drift rate of all gyros at launch were approximately .1 deg/hour, but the Y-gyro drift rate is currently approximately 5 deg/hour. The drift rate is not increasing monotonically, but has sometimes increased and sometimes decreased over long periods (days to weeks). The drift rates of the X and Z-gyros have not changed since launch and both remain below 0.1 deg/hour. Despite its drift rate increase, the Y-gyro performance is still adequate for attitude control. On Thurs, 16 Sep, the NEC engineers turned on the S-gyro (skew) to measure its drift rate. This gyro was tested briefly two years ago during the post-launch check-out period, but has not been turned on since. The S-gyro drift rate was measured on Thurs to be 0.04 deg/hour, which was essentially its launch value. Because this rate is so much lower than the Y-gyro drift rate, it was decided that on Monday, 20 Sep, the spacecraft control would be switched from X-, Y-, Z-gyro's to X-, Z-, and S-gyro's. This was accomplished and T. Kosugi has confirmed that there is an improvement in spacecraft attitude control. It should be noted that the performance of the Y-gyro is adequate for attitude control and could be used in the future if there are problems with the X-, Z- or S- gyro's. << Data Flow >> The reformatting and distribution of the Yohkoh data is going smoothly. The magneto-optical (MO) disk archive is being used extensively at ISAS. Daily Kitt Peak full frame magnetogram and He 10830 images (Yohkoh files GKM and GKI) are now being copied to ISAS and LPARL thanks to the effort of Nariaki Nitta. Daily total intensity and polarized radio images (Yohkoh files GNT and GNP) are now being copied from the Nobeyama Observatory. There are images going back go Apr-93 that were also copied on-line at LPARL and ISAS. We have been copying daily white light, calcium, and h-alpha images (Yohkoh files GBW, GBK, and GBH) from Big Bear for over a year. << Papers and Conferences >> An international meeting was held in Kofu, Japan during 6-10 Sep 1993, hosted by the solar group of the Nobeyama Radio Heliograph. There were three and a half long days of 15 minute talks and posters. There were many interesting papers and there were also many good discussions about the papers. Many flares are now being analyzed by various Yohkoh and Nobeyama team members. The loop-top flare brightening as seen by SXT is now being studied by several people. Sakao reported about that the "cornucopia" model seems to explain the relative foot-point brightest and spectral-hardness observations quite well. During this period ISAS was visited by many non- Japanese visitors, including M. Kundu, B. Schmieder, D. Zarro, R. Moore, J. Porter, P. Bornmann, G. Roumeliotis, D. Sime, and several others. Mons Morrison presented some SXT data at the Fourth JPL CCD Radiation workshop. The data showed the increase in the SXT CCD dark current and the appearance and disappearance of dark spikes. The dark current went through a drastic change after the Nov-92 entrance filter failure. Finally, the changes in the optical sensitivity due to prolonged x-ray exposure was shown. Page 4 << General Public Using SXT Images >> Linford continued working closely with Dennis di Cicco from Sky and Telescope to ensure that we get an SXT image on the "sunspot number" page every month. Linford also worked with Gloria Barnes (NASA Headquarters) and Sue Cauffman (SAIC) at the request of Bill Wagner to get them an SXT Tiff-format image for some Educational Lithograph release. Philippa Watson of MultiMedia Corporation in London sent her thanks for our help in providing the SXT imagery that is to be used in their "SolarSystem CDi" (a public education and information product). Bill Brown sent Dan Fiorucci of the Newton's Apple TV program for kids in St. Paul, Minn. the current SXT video tape in broadcast quality Beta. << Engineering Summary Table >> Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Sep-91 517 397 21174 3541 24715 5481 18.15 Oct-91 4106 2532 6393 12437 18830 3401 15.30 Nov-91 5291 2475 12149 14696 26845 10952 28.98 Dec-91 4858 3228 4983 16837 21820 6910 24.05 Jan-92 5544 3177 10084 5972 16056 6849 29.90 Feb-92 5305 2803 16932 11382 28314 12019 29.80 Mar-92 6248 2361 20367 2653 23020 9458 29.12 Apr-92 6751 3483 20157 5423 25580 12327 32.52 May-92 7032 3158 25464 4589 30053 13745 31.38 Jun-92 6417 3632 21648 12725 34373 14782 30.07 Jul-92 6345 3275 23941 10510 34451 14717 29.93 Aug-92 6572 2978 24207 11154 35361 13550 27.70 Sep-92 6087 2916 26832 20042 46874 15729 25.12 Oct-92 6743 2589 50985 14709 65694 23687 26.50 Nov-92 6658 2939 24416 14696 39112 12924 24.84 Dec-92 6775 2999 24253 6633 30886 12356 28.57 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 5619 2295 18670 1289 19959 8900 30.84 Total 157318 74523 645846 249159 895005 345701 27.86 Number of Full Frame Images Received: 157318 Number of Observing Region Images Received: 895005 Total: 1052323 Approximate Number of Shutter Moves/CCD Readouts: 1866859 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 Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) Oct-91 31.07 21.3 509 261 10.5 77.8 Nov-91 31.06 20.9 648 277 11.9 64.4 Dec-91 31.04 20.2 804 353 14.0 52.5 Jan-92 31.13 23.6 985 450 0.5 / 2 14.9 38.4 Feb-92 31.32 30.8 1176 544 14.3 31.7 Mar-92 31.47 36.5 1355 626 14.8 25.1 Apr-92 31.44 35.2 1323 610 23.8 / 4 14.6 22.8 May-92 31.65 43.1 1417 653 14.4 20.1 Jun-92 32.12 60.9 2215 880 -2.5 / 3 15.1 17.4 Jul-92 32.22 64.4 1852 832 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 45.07 546.3 27399 2726 17.3 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 travel for the month of September, 1993: FREELAND 1-SEP-93 * 24-SEP-93 24 (total of 24 days) HUDSON 1-SEP-93 * 15-SEP-93 15 (total of 15 days) LEMEN 1-SEP-93 * 21-SEP-93 21 28-SEP-93 30-SEP-93 * 3 (total of 24 days) MORRISON 27-SEP-93 30-SEP-93 * 4 (total of 4 days) SLATER 1-SEP-93 * 11-SEP-93 11 15-SEP-93 17-SEP-93 3 (total of 14 days) STRONG 1-SEP-93 * 12-SEP-93 12 (total of 12 days) Planned SXT travel for the month of October, 1993: FREELAND 19-OCT-93 31-OCT-93 * 13 (total of 13 days) HUDSON 1-OCT-93 14-OCT-93 14 23-OCT-93 31-OCT-93 * 9 (total of 23 days) LEMEN 1-OCT-93 * 31-OCT-93 * 31 (total of 31 days) MORRISON 1-OCT-93 * 22-OCT-93 22 (total of 22 days) NITTA 18-OCT-93 31-OCT-93 * 14 (total of 14 days) LEKA 19-OCT-93 31-OCT-93 * 13 (total of 13 days) Respectfully submitted, Mons D. Morrison Frank Friedlaender Page 7 -------------------------------------------------------------------------------- UNIVERSITY OF HAWAII ACTIVITY REPORT (DR. R. CANFIELD) No input required for this month -------------------------------------------------------------------------------- UNIVERSITY OF CALIFORNIA AT BERKELEY (DR. S. KANE) No input required for this month -------------------------------------------------------------------------------- STANFORD UNIVERSITY (DR. P. STURROCK) No input required for this month -------------------------------------------------------------------------------- SOLAR PHYSICS RESEARCH CORPORATION (KAREN L. HARVEY) No input required for this month -------------------------------------------------------------------------------- MONTANA STATE UNIVERSITY (LOREN ACTON) No input required for this month 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 | October 10, 1993 September 1993 |-------------------------------- | 6. PERFORMING ORGANIZATION | CODE: O/91-30 -----------------------------------------------|-------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- M. D. Morrison | 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, 1993 |-------------------------------- |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, Washington, D.C. 20402-0001