Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for the month of January, 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 Yohkoh and SXT continue to work well and, although the Sun has been relatively quiet, we continue to get fascinating data. We have lost some KSC passes to the Akebono satellite due to a problem with its ground station. << Solar Activity and Observation Planning >> There was an M flare on 13 Jan of which Yohkoh caught the peak and early decay. It was on the SW limb and we have a spectacular series of partial frame images of the high arcade that was formed as a result of the flare. There were at least 20 C-level flares during this period but we wont know how many of these were seen by Yohkoh until all the data is in from DSN and reformatted. On 14 Jan SXT observed a revealing loop evolution on the SE limb. The loop appeared initially with two sharply angled bends in it between the two active regions that it spanned. It was over 50,000 km high. As the loop steadily grew, the loop top first becomes more rounded and then square. The loop top then developed a series of localized kinks that grow as the loop dispersed into a complex of interleaved flux tubes. Solar activity was low the week of 17-Jan, with the GOES background declining from about B7 to below B2. There were 12 C flares recorded on GOES and the Sun was dominated by a large trans-equatorial coronal hole. It had similar characteristics to the coronal hole channel observed for several months last year. There are clearly visible some very high loops (open field lines?) along its southern boundary where it turns from a N-S orientation and sweeps westward, Page 2 becoming narrow. NOAA active regions 7403 and 7406 mark its western and eastern boundaries, respectively. There was and isolated "anemone" region in it in the northern hemisphere and several XBPs appeared and disappeared within its boundaries. During the week of 24-Jan, SXT observed two large coronal holes; one stretching from the northern polar hole across the equator and the other, about a 120 degrees behind the first in longitude, originating in the southern polar hole and stretching into the northern hemisphere. They have an interesting contrast in boundary characteristics; the northern hemisphere hole seems to have very low lying boundaries (angle of less than 45 degrees) whereas the southern coronal hole had high, curtain-like boundaries. "Active" Region 7407 produced a beautiful filament eruption on 26 Jan 93 before 17:46 UT. The bright, complex arcade it produced stretched over 100,000 km across the disk. It slowly grew and dimmed over the next day. This region produced several loop arcade activations on 27/28 Jan 93. The SXT observation plan was adjusted to support Bob Lin's balloon flight in early January. SXT also supported the flight of a grazing-incidence soft X-ray telescope built by Dan Moses. We have also opened discussions with Leon Golub for the support of the flight of his NIXT payload in March 93. << Data Analysis Software >> Gary Linford and Jim Lemen have been focusing on the reorganization of the SXT temperature software. Currently there are several "unofficial" programs, and it is the hope of the SXT team to create a single program which does all of the temperature and emission measure calculations. Extensive discussions have occurred with Jim McTiernan, who is the author of one of the "unofficial" programs. Progress is very encouraging and it is hoped that a completed version will be available in February. << Instrument Operations and Health >> Early in January it was observed that the SXT thin filter images were "freckled" with small dark spots. It is expected that these are from tiny droplets of condensate on the CCD. This was observed before in optical images but never in x-rays. The offending freckles disappeared after the CCD was baked out at +20C for 24 hours. We are sure glad that we decided to include a bakeout heater in the design of the SXT! We will repeat this bakeout about each 3 months. It is interesting that the CCD is still collecting contaminate after over one year in orbit--inside an instrument that we took every effort to keep clean and outgassing free. Page 3 The number of duty scientists has been decreased to 3 at ISAS and 2 at the KSC tracking station. SXT real time passes are no longer monitored at ISAS. Yohkoh is beginning to lose some station contacts to 2 other ISAS spacecraft, Akebono and Astro-D. Astro-D is presently in flight preparation at KSC aiming for a launch on about 12 February. During the week of 24-Jan, Yohkoh performed on of it's periodic offpoints to make a deep exposure of the high corona. While the offpoints worked flawlessly thanks to the hard work and talent of the SSOC and KCS tobans , the scientific results were a disappointment. The scattered light appears to make the long exposure unusable in each of the filters (Mg, Dag, thick Al) that we used. More quantitative statements need to be made, but new patterns of leaking light appeared with this orientation of the telescope. The operation itself was perfect, no glitches. The offpoint was from the patched OG, and the return was via BC's since the return OG had not been updated yet to allow for the re-point done to clear the HXA fiducial marks recently. << Data Flow >> A series of new problems have occurred when trying to access the mainframe SIRIUS database which holds the Yohkoh data. Many days have been lost with the reformatting effort, and the problems still do not seem to be solved. One error which resulted in not receiving all of the possible Yohkoh data has been solved, but it requires that we re-reformat 5 weeks which were just reformatted since December. On 15 January Dr. Lemen visited the solar data center at GSFC to discuss the entry of Yohkoh data into the archiving and public access system. The first year of Yohkoh data will be put into the system in September 1993--two years after Yohkoh launch. The same day Acton took advantage of the trip to Washington for further talks with NASA Code SS personnel and on Capitol Hill. He met with Drs. G. Withbroe, Director of Space Physics, and W. Wagner, Chief of Solar Physics to discuss extension of the SXT program beyond FY95. In a nutshell: (1) They are pleased with the SXT program and its results to date. (2) They intend to put extended operations and analysis in their MODA forward budget plan. (3) They can make no promises because of the extreme tightness of MODA in the years ahead. It should be noted that the present contract level of effort on SXT is about $3.3M/year, which includes all of the university Co-I's. << Problems >> The x-ray damaged limb regions are evident in the warm dark current at a level of about 3 times the normal dark current. Compared to the dark current "floor" the most strongly damaged areas in the 10-Sep-93 images are fainter than on 10-April-92 by about 25%. However, in absolute DN the damage peaks are about the same as before but the "floor" has moved up by about 50 DN per pixel. At this point it is not possible to tell whether or not the increased UV flood has annealed out some of the long term damage. Page 4 There is no evidence for any change in optical response after 17-Nov-92. Based upon the rate of decrease just before the entrance filter failed we would have expected a 10-15% change. We are able to monitor the optical response three different ways: (1) Diffuser images made with 0.8 msec exposures. (2) Dark (light leaks around the shutter) images with 0.8 msec exposure and the narrow band filter in place. (3) Stray light coming through a pinhole in the thin aluminum filter in the far lower left (SE) corner where x-ray contamination is minor--2.7 sec exposures. As almost all of the light is now coming through the hole in the entrance filter this result indicates that the aspect sensor decrease in signal was caused by loss of transmission of the entrance optics rather than some change in the CCD caused by trapped radiation damage. This continues to be a knotty problem to understand but is no longer of operational importance to SXT itself. << Papers and Conferences >> A 2-day workshop was held at ISAS on 8 and 9 January for informal discussions of work different people are doing with the SXT full resolution partial frame image data. On 14 January Drs. J. Lemen and L. Acton attended a workshop at NASA headquarters organized by Dr. Jim Willett of Code SS. The purpose of the workshop was to acquire inputs from flight project leaders of what were he drivers of mission operations costs. Space Physics faces an increasing gap between Mission Operations and Data Analysis (MODA) budget and the needs of the several flight projects over the next 5 years. The Yohkoh mission was unique among those considered because it is operated almost wholly by the science team--providing an automatic control on operations costs because no scientist would choose to do more than what is absolutely necessary of this kind of work. Although participation in this workshop is of no direct benefit to the SXT program it is beneficial that headquarters personnel understand the nature of our operations as SXT comes up for consideration of extended mission operations in FY95. There was a seminar by Professor Enome about the Nobeyama Radioheliograph. He showed some of the synthesized images that they have been obtaining from Nobeyama since it came into operation in June 1992. These images are of extremely high quality. He pointed out several collaborations that were underway with Yohkoh already and encouraged more such joint work in the future. There was a great deal of interesting debate about the filament eruption of 31 July 1992 which was observed by both SXT and the radioheliograph. It shows a rising arcade corresponding to the filament (presumably) visible in the 2-cm data and beneath it an exquisite arcade of X-ray emitting loops. Page 5 << Engineering Summary Table >> Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Sep-91 501 413 20914 3541 24455 5741 19.01 Oct-91 4095 2543 6389 12195 18584 3647 16.41 Nov-91 5276 2555 12173 14686 26859 10990 29.04 Dec-91 4834 3252 4940 16887 21827 6903 24.03 Jan-92 5544 3177 10084 5972 16056 6849 29.90 Feb-92 4670 3063 14720 9429 24149 14502 37.52 Mar-92 5910 2699 19236 2653 21889 10589 32.60 Apr-92 6751 3483 20157 5423 25580 12327 32.52 May-92 6765 3425 24473 4444 28917 14881 33.98 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 6655 3253 23217 4420 27637 12654 31.41 Total 96598 49191 352585 170119 522704 206828 28.35 Number of Full Frame Images Received: 96598 Number of Observing Region Images Received: 522704 Total: 619302 Approximate Number of Shutter Moves/CCD Readouts: 1135518 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 Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Temp /Days Temp (%) Oct-91 31.18 25.4 889 33321 10.5 78.6 Nov-91 31.06 21.0 651 34706 11.9 64.5 Dec-91 31.04 20.2 804 35175 14.0 52.6 Jan-92 31.15 24.2 1021 39160 0.5 / 2 14.9 38.4 Feb-92 31.32 30.9 1176 44654 14.3 31.8 Mar-92 31.47 36.5 1354 49535 14.8 25.1 Apr-92 31.44 35.2 1323 49325 23.8 / 4 14.6 22.8 May-92 31.65 43.1 1417 56822 14.4 20.1 Jun-92 32.11 60.3 2158 70647 -2.5 / 3 15.1 17.4 Jul-92 32.22 64.4 1852 79326 15.5 14.1 Aug-92 32.21 64.1 1922 77488 14.9 13.1 Sep-92 32.38 70.5 2062 84758 -1.2 / 3 15.9 12.2 Oct-92 32.64 80.3 2317 94956 16.8 11.5 Nov-92 36.06 208.5 5876 165111 18.0 11.0 Dec-92 42.58 452.8 17390 255840 17.9 N/A Jan-93 42.64 455.1 13388 261040 23.8 / 2 19.3 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. << Personnel Travel >> SXT Travel to ISAS for January, 1993 ACTON 5-JAN-93 13-JAN-93 9 (total of 9 days) HUDSON 1-JAN-93 * 31-JAN-93 * 31 (total of 31 days) LINFORD 5-JAN-93 31-JAN-93 * 27 (total of 27 days) NITTA 15-JAN-93 31-JAN-93 * 17 (total of 17 days) SLATER 11-JAN-93 31-JAN-93 * 21 (total of 21 days) STRONG 5-JAN-93 31-JAN-93 27 (total of 27 days) CANFIELD 11-JAN-93 31-JAN-93 * 21 (total of 21 days) Page 7 Planned travel to ISAS for February, 1993 HUDSON 1-FEB-93 * 11-FEB-93 11 19-FEB-93 30-FEB-93 * 12 (total of 23 days) LINFORD 1-FEB-93 * 10-FEB-93 10 17-FEB-93 30-FEB-93 * 14 (total of 24 days) NITTA 1-FEB-93 * 25-FEB-93 25 (total of 25 days) SLATER 1-FEB-93 * 26-FEB-93 26 (total of 26 days) STRONG 7-FEB-93 30-FEB-93 * 24 (total of 24 days) CANFIELD 1-FEB-93 * 5-FEB-93 5 21-FEB-93 27-FEB-93 7 (total of 12 days) METCALF 22-FEB-93 27-FEB-93 6 (total of 6 days WUELSER 21-FEB-93 27-FEB-93 7 (total of 7 days) HARVEY 7-FEB-93 1-MAR-93 23 (total of 23 days) KLIMCHUK 22-FEB-93 27-FEB-93 6 (total of 6 days) << Plans for February 1993 >> 1. Prepare for the Yohkoh Science Conference which will be held at ISAS from 23-Feb to 25-Feb. 2. Continue to complete the document package. 3. Continue the Data Analysis and Reduction software development effort. 4. Continue mission operations and data analysis at ISAS. Respectfully submitted, Mons D. Morrison Frank Friedlaender Page 8 -------------------------------------------------------------------------------- UNIVERSITY OF HAWAII ACTIVITY REPORT (DR. R. CANFIELD) No input required for this month -------------------------------------------------------------------------------- UNIVERSITY OF CALIFORNIA AT BERKELEY 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 Page 9 -------------------------------------------------------------------------------- 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 | February 10, 1993 January 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 January, 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 | 9 | ------------------------|------------------------|-----------------|------------ For sale by: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-0001 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ No. Delivered From Subject Lines 2 Jan 29 11:31 POSTMAN [From: >> Wednesday, Feb 10, 1993 12:43 PM PST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~