130:
1356:
138:
22:
92:
satellites. The high apogee meant that the polar regions were visible for long amounts of time, and only two satellites were required in order to achieve constant communications ability. In addition, two geostationary satellites appear to be part of the system. The SDS satellites were constructed by
141:
The SDS 3-4 satellite (USA 179, 2004-034A) created a tiny trail perpendicular to the star trails in this 10 second exposure with a Zeiss Sonnar MC 2.8/180mm lens made by amateur satellite observer Marco
196:
downlink. Two dishes are 4.5 m (15 ft) in diameter, while the third is 2 m (6 ft 7 in) in diameter. The solar arrays generate 1238 watts of power. It is believed that the
1267:
1171:
1897:
64:. The first generation was named simply 'SDS', the second generation was named 'Quasar' and the third generation each had their own designations.
1469:
771:
703:
643:
192:
The SDS-2 is significantly more massive at 2,335 kg (5,148 lb), with three separate communication dishes, including one for a
426:
379:
332:
285:
1887:
1293:
1239:
1193:
1144:
992:
944:
896:
845:
795:
1559:
736:
670:
610:
557:
780:
712:
652:
513:
469:
1524:
1507:
1322:
1220:
1122:
1071:
821:
1923:
1318:
1216:
1167:
1118:
1067:
1014:
966:
918:
867:
817:
1484:
1413:
583:
539:
495:
452:
405:
358:
311:
1928:
1264:
1018:
970:
922:
871:
1754:
1569:
1933:
1552:
1694:
1299:
1245:
1198:
1149:
1101:
1049:
997:
949:
901:
850:
800:
741:
675:
615:
562:
518:
474:
431:
384:
337:
290:
1643:
579:
535:
491:
448:
401:
354:
307:
1537:
238:
233:
106:
45:
1648:
1545:
760:
94:
73:
693:
633:
42:
197:
167:
1809:
1781:
1708:
1689:
1339:
1327:
1285:
776:
708:
648:
253:
174:
171:
147:
114:
60:
from 1998 to the present. It is believed that these satellites were known by the code name
8:
1814:
1773:
1733:
724:
159:
1791:
1786:
1728:
1723:
1597:
1428:
1361:
728:
110:
1837:
1749:
1684:
1664:
1521:
1504:
1409:
180:
It has been speculated that the early satellites served as data relays for the first
85:
1801:
163:
1824:
1528:
1511:
1441:
216:
89:
1406:
The
Wizards of Langley. Inside the CIA's Directorate of Science and Technology
105:
The primary purpose of the SDS satellites is to relay imagery from low-flying
1917:
1617:
1389:
1089:
1036:
889:
755:
688:
628:
193:
118:
26:
1627:
1622:
1607:
181:
166:. The SDS-1 had a mass of 630 kg (1,390 lb) and was launched on
1612:
1602:
574:
530:
486:
443:
396:
349:
302:
1470:"NROL-61 satellite launched Thursday spotted in space by sky-watchers"
1375:
129:
1567:
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rockets. The SDS-1 satellites had similar orbits to the Air Force's
1454:
1113:
1009:
961:
913:
862:
812:
213:
151:
1902:
1892:
1832:
1520:
Vick, Berman, Lindborg, Fellow, Pike, Aftergood (March 19, 1997)
1312:
1258:
1210:
1188:, geosynchronous satellite at 144° West, replacement for USA-162
1161:
1096:
1061:
1044:
258:
200:
has been used to launch several satellites, possibly on missions
137:
1866:
767:
699:
639:
263:
209:
205:
201:
1764:
81:
77:
21:
1882:
155:
117:
radar reconnaissance satellites to ground stations in the
1429:
1139:, geosynchronous satellite at 10° West, replaced USA-155
1433:
25:
The current SDS-3 constellation, consisting of three
1351:
154:
in shape, roughly 25 ft (7.6 m) long. 980
146:Each SDS-1 satellite had 12 channels available for
133:
Releasable
Picture of NRO satellite, possible SDS-1
1915:
1503:Vick, Berman, Lindborg, Fellow (March 19, 1997)
16:American military satellite communication system
723:Geosynchronous satellite, deployed along with
48:. At least three generations have been used:
1553:
1442:"Shadow dancing: the Satellite Data System"
1560:
1546:
67:
1403:
1397:
987:, geosynchronous satellite at 144° West
158:of electrical power were available from
136:
128:
20:
1522:SDS-2 Military Communications Satellite
1505:SDS-1 Military Communications Satellite
1485:"Atlas V finally launches with NROL-52"
939:, geosynchronous satellite at 10° West
1916:
1482:
84:in order to allow communications with
1541:
1408:. Boulder, Colorado: Westview Press.
76:, going from about 300 kilometers at
29:type and two geostationary satellites
602:
1483:Graham, William (15 October 2017).
1440:Day, Dwayne A. (26 February 2018).
1439:
837:
277:
13:
14:
1945:
1532:Federation of American Scientists
1515:Federation of American Scientists
727:and initially misidentified as a
1472:. Spaceflight Now. 30 July 2016.
1354:
212:. Other launches have used the
150:(UHF) communication. They were
1570:National Reconnaissance Office
1476:
1462:
1448:
1422:
1383:
1369:
1:
1347:
1288:, might be a new generation
222:
88:stations that cannot contact
80:to roughly 39,000 km at
7:
184:reconnaissance satellites.
113:optical reconnaissance and
10:
1950:
1457:List of satellite launches
835:
600:
275:
100:
1924:Communications satellites
1875:
1854:
1823:
1800:
1772:
1763:
1742:
1716:
1707:
1677:
1657:
1636:
1590:
1583:
1576:
1527:20 September 2016 at the
1455:Jonathan's Space Report:
1390:Jonathan's Space Report:
1376:Jonathan's Space Report:
1234:Geosynchronous satellite
656:
107:reconnaissance satellites
46:communications satellites
1404:Richelson, J.T. (2001).
1039:, final Atlas II launch
187:
124:
1929:Hughes Aircraft Company
1534:Accessed April 24, 2004
1517:Accessed April 24, 2004
95:Hughes Aircraft Company
74:highly elliptical orbit
68:Orbital characteristics
1510:28 August 2016 at the
143:
134:
72:SDS satellites have a
43:United States military
30:
1487:. NASASpaceFlight.com
140:
132:
35:Satellite Data System
24:
1340:Geosynchronous orbit
1286:Geosynchronous orbit
148:Ultra high frequency
1934:Military satellites
1444:. The Space Review.
1392:Satellite Catalogue
1378:NRO Satellite Names
56:from 1989 to 1996;
52:from 1976 to 1987;
1568:Satellites of the
1362:Spaceflight portal
731:SIGINT spacecraft
254:Launch designation
144:
135:
31:
1911:
1910:
1850:
1849:
1846:
1845:
1782:Rhyolite/Aquacade
1703:
1702:
1673:
1672:
1345:
1344:
1306:
1252:
1204:
1155:
1107:
1058:10 December 2007
1055:
1003:
955:
907:
856:
806:
747:
684:15 November 1990
681:
621:
603:Second generation
571:15 February 1987
568:
524:
480:
440:13 December 1980
437:
390:
343:
296:
241:
41:) is a system of
1941:
1770:
1769:
1714:
1713:
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1562:
1555:
1548:
1539:
1538:
1497:
1496:
1494:
1492:
1480:
1474:
1473:
1466:
1460:
1452:
1446:
1445:
1437:
1431:
1426:
1420:
1419:
1401:
1395:
1387:
1381:
1373:
1364:
1359:
1358:
1357:
1309:15 October 2017
1304:
1302:
1250:
1248:
1202:
1153:
1114:Delta IV-M+(4,2)
1105:
1053:
1001:
958:11 October 2001
953:
910:6 December 2000
905:
859:29 January 1998
854:
838:Third generation
804:
765:
758:
750:2 December 1992
745:
691:
679:
631:
619:
566:
527:8 February 1985
522:
478:
435:
388:
341:
294:
278:First generation
237:
227:
226:
1949:
1948:
1944:
1943:
1942:
1940:
1939:
1938:
1914:
1913:
1912:
1907:
1871:
1842:
1819:
1796:
1759:
1738:
1699:
1669:
1653:
1632:
1572:
1566:
1529:Wayback Machine
1512:Wayback Machine
1500:
1490:
1488:
1481:
1477:
1468:
1467:
1463:
1453:
1449:
1438:
1434:
1427:
1423:
1416:
1402:
1398:
1388:
1384:
1374:
1370:
1360:
1355:
1353:
1350:
1303:
1298:
1249:
1244:
1201:
1152:
1104:
1052:
1006:31 August 2004
1000:
952:
904:
853:
840:
803:
766:
754:
753:
744:
698:
687:
678:
638:
627:
618:
605:
565:
521:
483:28 August 1984
477:
434:
387:
340:
293:
280:
247:Launch vehicle
236:
225:
190:
127:
103:
70:
17:
12:
11:
5:
1947:
1937:
1936:
1931:
1926:
1909:
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1895:
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1806:
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1798:
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1761:
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1752:
1746:
1744:
1740:
1739:
1737:
1736:
1731:
1726:
1720:
1718:
1717:Radar location
1711:
1705:
1704:
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1700:
1698:
1697:
1692:
1687:
1681:
1679:
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1655:
1654:
1652:
1651:
1646:
1640:
1638:
1634:
1633:
1631:
1630:
1628:Kennen/Crystal
1625:
1620:
1615:
1610:
1605:
1600:
1594:
1592:
1585:
1578:
1574:
1573:
1565:
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1499:
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1475:
1461:
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1414:
1396:
1382:
1367:
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1365:
1349:
1346:
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1342:
1336:
1334:
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1330:
1325:
1316:
1310:
1307:
1296:
1290:
1289:
1279:
1277:
1275:
1273:
1270:
1262:
1256:
1253:
1242:
1236:
1235:
1232:
1230:
1228:
1226:
1223:
1214:
1208:
1205:
1196:
1190:
1189:
1183:
1181:
1179:
1177:
1174:
1165:
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1156:
1147:
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1140:
1134:
1132:
1130:
1128:
1125:
1116:
1111:
1110:11 March 2011
1108:
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976:
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848:
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839:
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828:
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824:
815:
813:Titan IV(405)A
810:
807:
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791:
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783:
774:
751:
748:
739:
733:
732:
721:
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664:
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613:
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575:Titan III(34)B
572:
569:
560:
554:
553:
551:
549:
547:
545:
542:
533:
531:Titan III(34)B
528:
525:
516:
510:
509:
507:
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503:
501:
498:
489:
487:Titan III(34)B
484:
481:
472:
466:
465:
463:
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459:
457:
455:
446:
444:Titan III(34)B
441:
438:
429:
423:
422:
420:
417:
414:
411:
408:
399:
397:Titan III(34)B
394:
393:5 August 1978
391:
382:
376:
375:
373:
370:
367:
364:
361:
352:
350:Titan III(34)B
347:
346:6 August 1976
344:
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329:
328:
326:
323:
320:
317:
314:
305:
303:Titan III(34)B
300:
297:
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281:
279:
276:
273:
272:
269:
266:
261:
256:
251:
248:
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242:
231:
224:
221:
217:launch vehicle
189:
186:
126:
123:
109:, notably the
102:
99:
90:geosynchronous
69:
66:
15:
9:
6:
4:
3:
2:
1946:
1935:
1932:
1930:
1927:
1925:
1922:
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1904:
1901:
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1896:
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1891:
1889:
1886:
1884:
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1880:
1878:
1874:
1868:
1865:
1863:
1860:
1859:
1857:
1855:Communication
1853:
1839:
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1753:
1751:
1748:
1747:
1745:
1743:Ship location
1741:
1735:
1732:
1730:
1729:Chalet/Vortex
1727:
1725:
1722:
1721:
1719:
1715:
1712:
1710:
1706:
1696:
1693:
1691:
1690:Lacrosse/Onyx
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1676:
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1509:
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1502:
1501:
1486:
1479:
1471:
1465:
1459:
1458:
1451:
1443:
1436:
1430:
1425:
1417:
1415:9780813340593
1411:
1407:
1400:
1394:
1393:
1386:
1380:
1379:
1372:
1368:
1363:
1352:
1341:
1337:
1335:
1333:
1331:
1329:
1326:
1324:
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1317:
1314:
1311:
1308:
1301:
1297:
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1292:
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1287:
1283:
1280:
1278:
1276:
1274:
1271:
1269:
1266:
1263:
1260:
1257:
1255:28 July 2016
1254:
1247:
1243:
1241:
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1237:
1233:
1231:
1229:
1227:
1224:
1222:
1218:
1215:
1212:
1209:
1206:
1200:
1197:
1195:
1192:
1191:
1187:
1184:
1182:
1180:
1178:
1175:
1173:
1169:
1166:
1163:
1160:
1158:20 June 2012
1157:
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1148:
1146:
1143:
1142:
1138:
1135:
1133:
1131:
1129:
1126:
1124:
1120:
1117:
1115:
1112:
1109:
1103:
1100:
1098:
1095:
1094:
1091:
1090:Molniya orbit
1087:
1084:
1082:
1080:
1078:
1075:
1073:
1069:
1066:
1063:
1060:
1057:
1051:
1048:
1046:
1043:
1042:
1038:
1037:Molniya orbit
1034:
1031:
1029:
1027:
1025:
1022:
1020:
1016:
1013:
1011:
1008:
1005:
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994:
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990:
986:
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931:
929:
926:
924:
920:
917:
915:
912:
909:
903:
900:
898:
895:
894:
891:
890:Molniya orbit
887:
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873:
869:
866:
864:
861:
858:
852:
849:
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844:
843:
834:
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829:
827:
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819:
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811:
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802:
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793:
790:
788:
786:
784:
782:
778:
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773:
769:
764:
763:
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756:Space Shuttle
752:
749:
743:
740:
738:
735:
734:
730:
726:
722:
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690:
689:Space Shuttle
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659:
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629:Space Shuttle
626:
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228:
220:
218:
215:
211:
207:
203:
199:
198:Space Shuttle
195:
185:
183:
178:
176:
173:
169:
165:
161:
157:
153:
149:
139:
131:
122:
120:
119:United States
116:
115:Lacrosse/Onyx
112:
108:
98:
96:
91:
87:
83:
79:
75:
65:
63:
59:
55:
51:
47:
44:
40:
36:
28:
27:Molniya orbit
23:
19:
1861:
1787:Magnum/Orion
1531:
1514:
1489:. Retrieved
1478:
1464:
1456:
1450:
1435:
1424:
1405:
1399:
1391:
1385:
1377:
1371:
1281:
1207:22 May 2014
1185:
1136:
1085:
1032:
984:
936:
885:
809:3 July 1996
761:
694:
634:
624:2 June 1989
299:2 June 1976
268:Inclination
250:Launch site
244:Launch date
191:
182:KH-11 Kennen
179:
177:satellites.
160:solar panels
145:
104:
71:
61:
57:
53:
49:
38:
34:
32:
18:
152:cylindrical
1918:Categories
1876:Technology
1491:15 October
1348:References
1010:Atlas IIAS
962:Atlas IIAS
937:Great Bear
914:Atlas IIAS
223:Satellites
142:Langbroek.
1300:2017-066A
1246:2016-047A
1199:2014-027A
1150:2012-033A
1102:2011-011A
1050:2007-060A
998:2004-034A
950:2001-046A
902:2000-080A
886:Capricorn
863:Atlas IIA
851:1998-005A
801:1996-038A
772:Orbus-21S
762:Discovery
742:1992-086B
704:Orbus-21S
676:1990-097B
644:Orbus-21S
616:1989-061B
563:1987-015A
500:SDS F-5A
475:1984-091A
432:1980-100A
419:63.3 deg
416:39315 km
385:1978-075A
372:63.3 deg
369:39315 km
338:1976-080A
325:63.3 deg
322:39315 km
291:1976-050A
234:COSPAR ID
164:batteries
1810:Jumpseat
1618:Gambit 3
1613:Gambit 1
1525:Archived
1508:Archived
1272:NROL-61
1225:NROL-33
1176:NROL-38
1127:NROL-27
1086:Scorpius
1076:NROL-24
975:NROL-12
927:NROL-10
695:Atlantis
635:Columbia
588:SDS F-6
519:195-014A
427:OPS 5805
410:SDS F-3
380:OPS 7310
363:SDS F-2
333:OPS 7940
316:SDS F-1
286:OPS 7837
271:Remarks
239:SATCAT №
214:Titan IV
172:Jumpseat
168:Titan-3B
1893:USA-193
1888:GeoLITE
1833:Samos-F
1815:Trumpet
1734:Mercury
1623:Hexagon
1608:Lanyard
1591:Keyhole
1584:Optical
1577:Imaging
1338:Likely
1328:NROL-52
1313:Atlas V
1294:USA-279
1259:Atlas V
1240:USA-269
1211:Atlas V
1194:USA-252
1162:Atlas V
1145:USA-236
1137:Gryphon
1123:SLC-37B
1097:USA-227
1062:Atlas V
1045:USA-198
1033:Nemesis
1023:NROL-1
1019:SLC-36A
993:USA-179
985:Aquilla
971:SLC-36B
945:USA-162
923:SLC-36A
897:USA-155
876:NROL-5
872:SLC-36A
846:USA-137
796:USA-125
725:Prowler
413:380 km
366:380 km
319:380 km
259:Perigee
111:Keyhole
101:Mission
78:perigee
1898:Colony
1867:SLDCOM
1792:Mentor
1724:Canyon
1709:SIGINT
1598:Corona
1412:
1323:SLC-41
1268:SLC-41
1221:SLC-41
1172:SLC-41
1072:SLC-41
781:LC-39A
768:STS-53
737:USA-89
729:Magnum
713:LC-39A
700:STS-38
671:USA-67
653:LC-39B
640:STS-28
611:USA-40
584:SLC-4W
558:USA-21
544:USA-9
540:SLC-4W
496:SLC-4W
453:SLC-4W
406:SLC-4W
359:SLC-4W
312:SLC-4W
264:Apogee
210:STS-53
208:, and
206:STS-38
202:STS-28
194:K-band
82:apogee
62:Quasar
1838:Poppy
1765:ELINT
1750:Poppy
1695:FIA-R
1685:Quill
1678:Radar
1665:Samos
1658:Other
1644:Misty
1637:Misty
1603:Argon
1319:CCAFS
1305:42973
1282:Spike
1265:CCAFS
1251:41724
1217:CCAFS
1203:39751
1186:Drake
1168:CCAFS
1154:38466
1119:CCAFS
1106:37377
1068:CCAFS
1054:32378
1015:CCAFS
1002:28384
967:CCAFS
954:26948
919:CCAFS
906:26635
868:CCAFS
855:25148
822:LC-40
818:CCAFS
805:23945
759:
746:22518
692:
680:20963
632:
620:20167
567:17506
523:15546
514:USA-9
479:15226
470:USA-4
436:12093
389:10993
342:09270
295:08871
230:Name
188:SDS-2
175:ELINT
156:watts
125:SDS-1
86:polar
58:SDS-3
54:SDS-2
50:SDS-1
1883:STEX
1755:NOSS
1493:2017
1410:ISBN
1315:421
1261:421
1213:401
1164:401
1064:401
657:N/A
580:VAFB
536:VAFB
492:VAFB
449:VAFB
402:VAFB
355:VAFB
308:VAFB
162:and
33:The
1903:RPP
1862:SDS
1825:LEO
1802:HEO
1774:GEO
1649:EIS
777:KSC
709:KSC
649:KSC
39:SDS
1920::
1321:,
1284:,
1219:,
1170:,
1121:,
1088:,
1070:,
1035:,
1017:,
969:,
921:,
888:,
870:,
820:,
779:,
711:,
651:,
582:,
538:,
494:,
451:,
404:,
357:,
310:,
219:.
204:,
121:.
97:.
1561:e
1554:t
1547:v
1495:.
1418:.
770:/
702:/
642:/
37:(
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