SPX-516 25 October 1996 SPACEWARN Activities A publication of NASA NSSDC/WDC-A-R&S and the WWAS for ISES/COSPAR (All information in this publication was received between 25 September 1996 and 24 October 1996.) A. List of New International Designations and Launch Dates (UT). (USSPACECOM Catalog numbers are in parentheses.) 1996-060A (24640) MOLNIYA 3-48 24 Oct 1996-059A (24634) FSW-2 3 20 Oct 1996-058A (24435) EXPRESS 12 26 Sep B. Text of Launch Announcements. 1996-060A MOLNIYA 3-48 is a Russian communications spacecraft that was launched by a Molniya-M booster from Plesetsk at 11:37 UT. It will provide voice and video communications throughout Russia. It will also carry a "hot line" between Moscow and Washington. Initial orbital parameters were period 736.3 min, apogee 40,649 km, perigee 608 km, and inclination 62.8 deg. 1996-059A FSW-2 3 is a PRC remote sensing satellite that was launched by a Long March 3 rocket from Xichuan. Initial orbital parameters were period 89.6 min, apogee 332 km, perigee 168 km, and inclination 63 deg. 1996-058A EXPRESS 12 is a Russian geostationary spacecraft that was launched by a Proton booster from Baykonur at 21:51 UT. The EXPRESS class is an updated version of the discontinued GORIZONT class. The 2,500 kg spacecraft attained geostationary orbit about eight hours after launch and will provide video and voice communications throughout Russia. C. Spacecraft Particularly Suited for International Participation. 1. Spacecraft with essentially continuous radio beacons on frequencies less than 150 MHz, or higher frequencies if especially suited for ionospheric or geodetic studies. (NNSS denotes U.S. Navy Navigational Satellite System; an asterisk [*] indicates updated/new information since the last issue. Updates or corrections to the list are possible only with information from the user community.) THE FULL LIST APPEARED in SPX-513; A SMALL REVISION APPEARED IN SPX-515. THE LIST WILL APPEAR AGAIN ONLY WHEN MAJOR UPDATES ARE MADE. 2. Global Positioning System satellites useful for navigational purposes and geodetic studies. ("NNN" denotes no national name. SPACEWARN Bulletin appreciates suggestions to update this list. An asterisk [*] denotes changes in this issue. The SPACEWARN Bulletin thanks Richard Langley of the University of New Brunswick for the update.) High precision (< 20 cm) GPS constellation tracking data obtained from the network of about 80 dedicated global stations that are of interest to geodetic study may be obtained through the following services provided by the International Association of Geodesy (IGS). FTP: igscb.jpl.nasa.gov [directory /igscb] WWW: http://igscb.jpl.nasa.gov/ E-Mail: igscb@cobra.jpl.nasa.gov The standard format of the GPS information appeared in SPX-515. The following E-mail from Richard Langley may be more useful to the user community. From: SMTP%"lang@unb.ca" 7-OCT-1996 12:10:52.26 To: SARDI CC: Subj: Navstar GPS Constellation Status (96-10-07) Navstar GPS Constellation Status (96-10-07) Blk NORAD Orbit Launch II PRN Internat. Catalog Plane Date Seq SVN Code ID Number Pos'n (UT) Clock Available/Decommissioned ------------------------------------------------------------------------------- Block I 01 04 1978-020A 10684 78-02-22 78-03-29 85-07-17 02 07 1978-047A 10893 78-05-13 78-07-14 81-07-16 03 06 1978-093A 11054 78-10-06 78-11-13 92-05-18 04 08 1978-112A 11141 78-12-10 79-01-08 89-10-14 05 05 1980-011A 11690 80-02-09 80-02-27 83-11-28 06 09 1980-032A 11783 80-04-26 80-05-16 91-03-06 07 81-12-18 Launch failure 08 11 1983-072A 14189 83-07-14 83-08-10 93-05-04 09 13 1984-059A 15039 84-06-13 84-07-19 94-06-20 10 12 1984-097A 15271 84-09-08 84-10-03 95-11-18 11 03 1985-093A 16129 85-10-09 85-10-30 94-04-13 Block II II-1 14 14 1989-013A 19802 E-1 89-02-14 Cs 89-04-15 05:02 UT II-2 13 02 1989-044A 20061 B-3 89-06-10 Cs 89-08-10 20:46 UT II-3 16 16 1989-064A 20185 E-5 89-08-18 Cs 89-10-14 20:21 UT II-4 19 19 1989-085A 20302 A-4 89-10-21 Rb 89-11-23 03:13 UT II-5 17 17 1989-097A 20361 D-3 89-12-11 Cs 90-01-06 03:30 UT II-6 18 18 1990-008A 20452 F-3 90-01-24 Cs 90-02-14 22:26 UT II-7 20 20 1990-025A 20533 90-03-26 90-04-18 96-05-10 II-8 21 21 1990-068A 20724 E-2 90-08-02 Cs 90-08-22 15:00 UT II-9 15 15 1990-088A 20830 D-2 90-10-01 Cs 90-10-15 00:39 UT Block IIA II-10 23 23 1990-103A 20959 E-4 90-11-26 Cs 90-12-10 23:45 UT II-11 24 24 1991-047A 21552 D-1 91-07-04 Rb 91-08-30 04:44 UT II-12 25 25 1992-009A 21890 A-2 92-02-23 Cs 92-03-24 11:00 UT II-13 28 28 1992-019A 21930 C-5 92-04-10 Cs 92-04-25 20:32 UT II-14 26 26 1992-039A 22014 F-2 92-07-07 Cs 92-07-23 19:43 UT II-15 27 27 1992-058A 22108 A-3 92-09-09 Cs 92-09-30 20:08 UT II-16 32 01 1992-079A 22231 F-1 92-11-22 Cs 92-12-11 14:49 UT II-17 29 29 1992-089A 22275 F-4 92-12-18 Cs 93-01-05 16:39 UT II-18 22 22 1993-007A 22446 B-1 93-02-03 Cs 93-04-04 05:20 UT II-19 31 31 1993-017A 22581 C-3 93-03-30 Rb 93-04-13 20:53 UT II-20 37 07 1993-032A 22657 C-4 93-05-13 Cs 93-06-12 16:15 UT II-21 39 09 1993-042A 22700 A-1 93-06-26 Cs 93-07-20 12:54 UT II-22 35 05 1993-054A 22779 B-4 93-08-30 Cs 93-09-28 19:29 UT II-23 34 04 1993-068A 22877 D-4 93-10-26 Cs 93-11-22 18:20 UT II-24 36 06 1994-016A 23027 C-1 94-03-10 Cs 94-03-28 14:20 UT II-25 33 03 1996-019A 23833 C-2 96-03-28 Cs 96-04-09 21:17 UT II-26 40 10 1996-041A 23953 E-3 96-07-16 Rb 96-08-15 15:05 UT II-27 30 30 1996-056A 24320 B-2 96-09-12 Cs 96-10-01 15:28 UT Notes ----- 1. NORAD Catalog Number is also known as U.S. Space Command (USSPACECOM) object number. 2. No orbital plane position = satellite no longer operational. 3. Clock: Rb = Rubidium; Cs = Cesium. 4. Selective Availability (S/A) had been enabled on Block II satellites during part of 1990; S/A off between about 10 August 1990 and 1 July 1991 due to Gulf crisis; standard level re-implemented on 15 November 1991; occasionally off for test and other purposes. Currently, PRN15 and PRN28 appear to have little or no S/A imposed. 5. Anti-spoofing (A-S) was activated on 94-01-31 at 00:00 UT on all Block II satellites (ref. NANU 050-94042); occasionally off for test and other purposes. A-S was turned off on all satellites at 20:00 UT on 95-04-19 and back on on 95-05-10; off again between 95-06-19 and 95-07-10; and between 95-10-10 and 95-10-31. A-S has been off on PRN28 since 95-02-21. 6. PRN number of SVN32 was changed from 32 to 01 on 93-01-28. 7. The active clock on PRN01 was switched from a Rb to a Cs between 96-08-16 and 96-08-22 (ref. USNO and NANUs 134-96229 and 141-96234). 8. PRN05 and PRN06 are equipped with corner-cube reflectors for satellite laser ranging (SLR). SLR tracking of the satellites will permit onboard clock errors and satellite ephemeris errors in GPS tracking to be differentiated. 9. The decommissioning date for PRN06/SVN03 is the date of termination of operations of this satellite (ref. USNO) and is about 3 weeks later than other published dates for "deactivation". 10. PRN16 will be moved from the E-3 slot to the E-5 slot to make room for PRN10. An orbit maneouvre was carried out on 96-08-19 (ref. NANUs 120-96204, 137-96232). 11. PRN20 has been unusable since 15:18 UT on 96-05-10 and will not return to service (ref. NANU 118-96204). Cause of failure: loss of 3-axis stabilisation. PRN20 was moved out of the B-2 slot to make room for PRN30 (ref. NANU 162-96256). 12. PRN28 has been moved from the C-2 slot to the C-5 slot, about 40 degrees away. This move, which was initiated on 96-03-06 by lowering the orbit of PRN28 by about 6 km, made way for PRN03. PRN03 is a backup for PRN28 which has some undisclosed equipment problem. PRN28 will remain on the air, with some subsystems shut down to conserve power (ref. NANUs 045-96066, NANU 068-96100, and GPS World Newsletter). The move was completed on 96-08-23 (ref. NANUs 127-96236 and 144-96236). 13. PRN30 (SVN30) was launched on 96-09-12 at 08:49 UT. It achieved initial usable status on 96-10-01 at 15:28 UT (ref. NANUs 162-96256 and 171-96275). 14. Announced date of next scheduled launch: 97-01-13 (first Block IIR satellite). 15. Compiled by Richard B. Langley, Dept. of Geodesy and Geomatics Engineering, University of New Brunswick. =============================================================================== Richard B. Langley Internet: LANG@UNB.CA or SE@UNB.CA Geodetic Research Laboratory BITnet: LANG@UNB or SE@UNB Dept. of Geodesy and Geomatics Engineering Phone: (506) 453-5142 University of New Brunswick FAX: (506) 453-4943 Fredericton, N.B., Canada E3B 5A3 Telex: 014-46202 Fredericton? Where's that? See: http://degaulle.hil.unb.ca/NB/fredericton.html =============================================================================== 3. Russian Global Navigational (Positioning) Spacecraft, GLONASS constellation. (SPACEWARN requests updates/additions from readers to this list. An asterisk [*] indicates updates or additions to the list.) All GLONASS spacecraft are in the general COSMOS series. The COSMOS numbers invoked by USSPACECOM have sometimes differed from the numbers (NNNN) associated in Russia. The corresponding GLONASS numbers are Russian numbers. The operating frequencies in MHz are computed from the channel number K. Frequencies (MHz) are L1 = 1602.0 + 0.5625K and L2 = 1246.0 + 0.4375K. The standard format of the GLONASS situation appeared in SPX-515. The following E-mail from CSIC may be more useful to the user community. From: AMES::"sfcsic@iki.rssi.ru" "CSIC of Russian Space Forces" 25-OCT-1996 04:38:55.45 To: Willem Baan , Peter Daly , Jeoff Evens , Arne Jungstand , Richard Langley , Levenets Ivan , Pratap Misra , "Mr.Parthasarathy" , Georg Weber , MAHOOTI SHAHRZAD AIRSYS/MTF CC: Subj: LATEST GLONASS CONSTELLATION STATUS 1.STATUS Information Group GLONASS Constellation Status (October 25, 1996) GLONASS Cosmos Plane/ Frequ. Launch Intro Status Outage number number slot chann. date date date 769 2178 1/8 2 30.01.92 22.02.92 operating 771 2179 1/1 23 30.01.92 18.02.92 operating 756 2204 3/21 24 30.07.92 19.08.92 operating 759 2235 1/7 21 17.02.93 25.08.93 operating 757 2236 1/2 5 17.02.93 14.03.93 operating 758 2275 3/18 10 11.04.94 04.09.94 operating 760 2276 3/17 24 11.04.94 18.05.94 operating 761 2277 3/23 3 11.04.94 16.05.94 operating 767 2287 2/12 22 11.08.94 07.09.94 operating 770 2288 2/14 9 11.08.94 04.09.94 operating 775 2289 2/16 22 11.08.94 07.09.94 operating 762 2294 1/4 12 20.11.94 11.12.94 operating 763 2295 1/3 21 20.11.94 15.12.94 operating 764 2296 1/6 13 20.11.94 16.12.94 operating 765 2307 3/20 1 07.03.95 30.03.95 operating 766 2308 3/22 10 07.03.95 05.04.95 operating 777 2309 3/19 3 07.03.95 06.04.95 operating 780 2316 2/15 4 24.07.95 26.08.95 operating 781 2317 2/10 9 24.07.95 22.08.95 operating 785 2318 2/11 4 24.07.95 22.08.95 operating 776 2323 2/9 6 14.12.95 07.01.96 operating 778 2324 2/9 11 14.12.95 spare 782 2325 2/13 6 14.12.95 18.01.96 operating Note: All the dates (DD.MM.YY) are given at Moscow Time (UTC+0300) 2.SUMMARY Information Group SUBJ:GLONASS STATUS 25 OCTOBER 96 1.SATELLITES, PLANES, SLOTS AND CHANNELS Plane 1/ slot: 01 02 03 04 05 06 07 08 Channel: 23 05 21 12 -- 13 21 02 Plane 2/ slot: 09 10 11 12 13 14 15 16 Channel 06 09 04 22 06 09 04 22 Plane 3/ slot: 17 18 19 20 21 22 23 24 Channel: 24 10 03 01 24 10 03 -- 2.CURRENT ADVISORIES (ADV) AND FORECASTS (FCST) INFORMATION IS REPEATED FOR ONE MONTH AFTER EVENT CONCLUDES. ALL THE DATES (DD.MM.YY) ARE GIVEN AT MOSCOW TIME (UTC+0300) A. FORECASTS NAGU-MSG.DATE-TIME-SL/CH-TYPE-SUMMARY 209-961010-10.10.96-1100-10/09-FCST-OUTAGE 12.10/1858-12.10/1903 210-961010-10.10.96-1100-09/06-FCST-OUTAGE 12.10/1728-12.10/1758 211-961010-10.10.96-1100-12/22-FCST-OUTAGE 12.10/1707-12.10/1737 215-961021-21.10.96-1100-15/04-FCST-PUT INTO OPERATION 24-25.10 216-961024-24.10.96-1100-15/04-FCST-PUT INTO OPERATION 24.10/1554 B. ADVISORIES NAGU-MSG.DATE-TIME-SL/CH-TYPE-SUMMARY 204-960930-30.09.96-1100-07/21-ADVS-UNUSABLE 29.09/0035-29.09/0834 207-961008-08.10.96-1100-04/12-ADVS-UNUSABLE 08.10/0622-UNFINISHED 208-961009-09.10.96-1100-04/12-ADVS-PUT INTO OPERATION 08.10/1545 212-961014-14.10.96-1100-10/09-ADVS-UNUSABLE 12.10/1858-12.10/1903 213-961014-14.10.96-1100-09/06-ADVS-UNUSABLE 12.10/1728-12.10/1758 214-961014-14.10.96-1100-12/22-ADVS-UNUSABLE 12.10/1707-12.10/1737 217-961025-25.10.96-1100-15/04-ADVS-PUT INTO OPERATION 24.10/1559 C. GENERAL: NO IMPACT, INFORMATIONAL PURPOSE ONLY NAGU-MSG.DATE-TIME-SL/CH-TYPE-SUMMARY 3.NAGU Information Group 204-960930 NOTICE ADVISORY TO GLONASS USERS (NAGU) 204-960930 SUBJ: 07/21(759) UNUSABLE 29.09/0035 MT - 29.09/0834 MT 1.CONDITION: 07/21(759) WAS UNUSABLE SINCE 29.09/0035 MT (UTC+0300) UNTIL 29.09/0834 MT (UTC+0300) 2.POC: CSIC RSF AT +7-095-330-91-74 205-961001 NOTICE ADVISORY TO GLONASS USERS (NAGU) 205-961001 SUBJ: 20/01(765) UNUSABLE 30.09/1551 MT-UNFINISHED 1.CONDITION: 20/01(765) WAS UNUSABLE SINCE 30.09/1551 MT (UTC+0300) UNTIL FURTHER NOTICE DUE TO MAINTENANCE 2.USERS ARE REMINDED TO UPDATE ALMANACS IF NECESSARY 3.POC: CSIC RSF AT +7-095-330-91-74 206-961007 NOTICE ADVISORY TO GLONASS USERS (NAGU) 206-961007 SUBJ: 20/01(765) PUT INTO OPERATION IN 06.10/0500 (UTC+0300) 1.CONDITION: 20/01(765) WAS PUT INTO OPERATION ON 06.10/0500 MT (UTC+0300) 2.USERS ARE REMINDED TO UPDATE ALMANACS IF NECESSARY 3.POC: CSIC RSF AT +7-095-330-91-74 207-961008 NOTICE ADVISORY TO GLONASS USERS (NAGU) 207-961008 SUBJ: 04/12(762) UNUSABLE 08.10/0622 MT-UNFINISHED 1.CONDITION: 04/12(762) WAS UNUSABLE SINCE 08.10/0622 MT (UTC+0300) UNTIL FURTHER NOTICE DUE TO MAINTENANCE 2.USERS ARE REMINDED TO UPDATE ALMANACS IF NECESSARY 3.POC: CSIC RSF AT +7-095-330-91-74 208-961009 NOTICE ADVISORY TO GLONASS USERS (NAGU) 208-961009 REF: NAGU 207-961008 SUBJ: 04/12(762) PUT INTO OPERATION IN 08.10/1545 (UTC+0300) MT 1.CONDITION: 04/12(762) WAS PUT INTO OPERATION ON 08.10/1545 MT (UTC+0300) 2.USERS ARE REMINDED TO UPDATE ALMANACS IF NECESSARY 3.POC: CSIC RSF AT +7-095-330-91-74 209-961010 NOTICE ADVISORY TO GLONASS USERS (NAGU) 209-961010 SUBJ: FORECAST OUTAGE SUMMARY 10/09(781) 12.10/1858-12.10/1903 MT 1.CONDITION: 10/09(781) IS SCHEDULED TO BE UNUSABLE ON 12.10/1858 UNTIL 12.10/1903 MT (UTC+0300) DUE TO MAINTENANCE 2.POC: CSIC RSF AT +7-095-330-91-74 210-961010 NOTICE ADVISORY TO GLONASS USERS (NAGU) 210-961010 SUBJ: FORECAST OUTAGE SUMMARY 09/06(776) 12.10/1728-12.10/1758 MT 1.CONDITION: 09/06(776) IS SCHEDULED TO BE UNUSABLE ON 12.10/1728 UNTIL 12.10/1758 MT (UTC+0300) DUE TO MAINTENANCE 2.POC: CSIC RSF AT +7-095-330-91-74 211-961010 NOTICE ADVISORY TO GLONASS USERS (NAGU) 211-961010 SUBJ: FORECAST OUTAGE SUMMARY 12/22(767) 12.10/1707-12.10/1737 MT 1.CONDITION: 12/22(767) IS SCHEDULED TO BE UNUSABLE ON 12.10/1707 UNTIL 12.10/1737 MT (UTC+0300) DUE TO MAINTENANCE 2.POC: CSIC RSF AT +7-095-330-91-74 212-961014 REF: NAGU 209-961010 NOTICE ADVISORY TO GLONASS USERS (NAGU) 212-961014 SUBJ: 10/09(781) UNUSABLE 12.10/1858-12.10/1903 MT 1.CONDITION: 10/09(781) WAS UNUSABLE SINCE 12.10/1858 UNTIL 12.10/1903 MT (UTC+0300) 2.POC: CSIC RSF AT +7-095-330-91-74 213-961014 REF: NAGU 210-961010 NOTICE ADVISORY TO GLONASS USERS (NAGU) 213-961014 SUBJ: 09/06(776) UNUSABLE 12.10/1728-12.10/1758 MT 1.CONDITION: 09/06(776) WAS UNUSABLE SINCE 12.10/1728 UNTIL 12.10/1758 MT (UTC+0300) 2.POC: CSIC RSF AT +7-095-330-91-74 214-961014 REF: NAGU 211-961010 NOTICE ADVISORY TO GLONASS USERS (NAGU) 214-961014 SUBJ: 12/22(767) UNUSABLE 12.10/1707-12.10/1737 MT 1.CONDITION: 12/22(767) WAS UNUSABLE SINCE 12.10/1707 UNTIL 12.10/1737 MT (UTC+0300) 2.POC: CSIC RSF AT +7-095-330-91-74 215-961021 NOTICE ADVISORY TO GLONASS USERS (NAGU) 215-961021 SUBJ: 15/04(780) FORECAST PUT INTO OPERATION 24-25.10 1.CONDITION: 15/04(780) IS SCHEDULED TO BE OPERATIONAL ON 24-25.10 AFTER MAINTENANCE 2.POC: CSIC RSF AT +7-095-330-91-74 216-961024 NOTICE ADVISORY TO GLONASS USERS (NAGU) 216-961024 SUBJ: 15/04(780) FORECAST PUT INTO OPERATION 24.10/1554 MT 1.CONDITION: 15/04(780) IS SCHEDULED TO BE OPERATIONAL ON 24.10/1554 MT (UTC+0300) AFTER MAINTENANCE 2.POC: CSIC RSF AT +7-095-330-91-74 217-961025 NOTICE ADVISORY TO GLONASS USERS (NAGU) 217-961025 REF: NAGU 216-961024 SUBJ: 15/04(780) PUT INTO OPERATION IN 24.10/1559 (UTC+0300) MT 1.CONDITION: 15/04(780) WAS PUT INTO OPERATION ON 24.10/1559 MT (UTC+0300) 2.USERS ARE REMINDED TO UPDATE ALMANACS IF NECESSARY 3.POC: CSIC RSF AT +7-095-330-91-74 ------------------------------------------------------------------------- Mail: PO BOX 14, Coordinational Scientific Moscow, 117279 ,Russia Information Center (CSIC) Russian Space Forces Tel: +7 095 333-81-33 RUSSIA, Moscow, Profsoyuznaya ulitsa, 84/32. +7 095 330-91-74 Fax: +7 095 334-23-00 E-mail: sfcsic@mx.iki.rssi.ru Home page WWW.IKI: http://www.rssi.ru/SFCSIC/SFCSIC_main.html ------------------------------------------------------------------------- 4. Actual decays/landings of payload spacecraft and rocket bodies (R/B) only. No further information is available. Designations Common Name 1996 1991-079F (21794) R/B SL-12 15 Oct 1986-057D (16889) R/B SL-6 14 Oct 1996-035B (23916) R/B ARIANE 44P 30 Sep 1996-058B (24436) R/B SL-12 29 Sep 1995-051A (23674) COSMOS 2320 28 Sep 1996-057A (24324) STS 79 Landed on 26 Sep 5. Miscellaneous Items. (This section contains information/data that are entered on occasion and may not be repeated in each issue of the SPACEWARN Bulletin.) For several weeks after the launch of the FAST spacecraft (1996-049A), its two-line orbital elements were carried under the NORAD Catalog number 24286 and International ID 1996-049B. The situation was corrected in early October, and the elements are now available under the catalog number 24285 and ID 1996-049A. NSSDC/WDC-A-R&S is an archival center for science data from many spacecraft. Some data are on line for electronic access. Please contact the Request Office, NSSDC, Code 633, NASA GSFC, Greenbelt, Maryland 20771, U.S.A., for specific information (REQUEST@NSSDCA.GSFC.NASA.GOV). Information on the current status of the instruments on board from the investigators will be most welcomed. Precomputed trajectory files and orbital parameters of many magnetospheric and heliospheric science-payload spacecraft may be FTP'ed from NSSDC's ANON_DIR:[000000.ACTIVE] and its several subdirectories. (See the last page of the bulletin for the access method; a file in the ACTIVE directory named AAREADME.DOC outlines the contents.) It can also be accessed through the WWW URL http://sscop1.gsfc.nasa.gov/ssc.html This HTML also enables executing several codes related to the orbits of many geocentric science payload spacecraft. The codes related to the heliospheric spacecraft trajectories can be executed through the URL http://nssdc/space/helios/heli.html Magnetospheric, planetary, and astronomical science data from many spacecraft may be accessed through links from the URL http://nssdc.gsfc.nasa.gov/ SPACEWARN Bulletin ------------------ The Bulletin is intended to serve as an international communication medium for the rapid distribution of information on satellites and space probes. The material it contains is based on guidelines in the COSPAR Guide to Rocket and Satellite Information and Data Exchange, COSPAR Transactions #8, December 1972, and various Committee on Space Research (COSPAR) resolutions. Hard copy recipients and electronic accessers are encouraged to disseminate the bulletin to interested individuals and institutions in their regions or countries. All bulletins beginning with January 1991 (SPX-447) are now available on line; the SPX number increases by one for each succeeding month (for example, the January 1993 bulletin is SPX-471). Through DECnet: At prompt type: copy nssdca::anon_dir:[000000.active.spx]spx.471 Through FTP: At prompt type: ftp nssdca.gsfc.nasa.gov At the next prompt type: anonymous At the PASSWORD (NSSDCA.GSFC.GOV.ANONYMOUS) prompt hit: return At the next prompt type: get anon_dir:[000000.active.spx]spx.471 spx.471 Other subdirectories in [000000.active] carry many files of interest on science payload spacecraft. The bulletin may also be accessed through the World Wide Web (WWW). The URL is http://nssdc.gsfc.nasa.gov/spacewarn/spacewarn.html. Users are urged to submit their comments and suggestions for the improvement of this bulletin to SPACEWARN Bulletin, World Data Center-A for Rockets and Satellites, Code 633, Goddard Space Flight Center, Greenbelt, Maryland 20771 U.S.A. Categories of Spacecraft To improve the effectiveness of international distribution of satellite and space probe information via the SPACEWARN system, spacecraft are identified in categories according to the urgency and detail of information needed by the scientific community as follows: CATEGORY 1: Spacecraft that carry essentially continuous telemetry or radio beacons, usually on frequencies less than 150 MHz. CATEGORY 2: GPS constellation of positioning/navigational spacecraft. CATEGORY 3: GLONASS constellation of positioning/navigational spacecraft. CATEGORY 4: Occassionally, a list of bright, orbiting objects of visual magnitude 4 or brighter. The bulletin also carries launch dates, international ID's and USSPACECOM catalog numbers, followed by a brief outline of the payload and orbital parameters, re-entry of major objects, and miscellaneous sections. These data are based on launch announcements or on information received from individuals, launching authorities, FBIS and USSPACECOM telexes, and news magazines.