29:
257:
satellites are punctured by orbiting space debris—calculated to be 8 percent over any 50-year period—and release their remaining NaK coolant into space. The coolant self-forms into frozen droplets of solid sodium-potassium of up to around several centimeters in size, and these solid objects then
165:. The satellite failed to boost into a nuclear-safe storage orbit as planned. Nuclear materials re-entered the Earth's atmosphere on 24 January 1978 and left a trail of radioactive pollution over an estimated 124,000 square kilometres of
179:. Failed to boost into storage orbit in late 1982. The reactor core was separated from the remainder of the spacecraft and was the last piece of the satellite to return to Earth, landing in the South Atlantic Ocean on 7 February 1983.
247:
of 269 years. There is no risk of surface contamination, as the droplets will burn up completely in the upper atmosphere on re-entry and the argon, a chemically inert gas, will dissipate. The major risk is impact with operational
90:
Because a return signal from an ordinary target illuminated by a radar transmitter diminishes as the inverse of the fourth power of the distance, for the surveillance radar to work effectively, US-A satellites had to be placed in
110:. Normally the nuclear reactor cores were ejected into high orbit (a so-called "disposal orbit") at the end of the mission, but there were several failure incidents, some of which resulted in radioactive material re-entering the
141:(RTGs) do not generate significant gamma radiation as compared with unshielded satellite fission reactors, and all of the BES-5-containing spacecraft orbited too low to cause positron pollution in the magnetosphere.
41:
133:) which were each capable of operating for six months. The higher-orbiting TOPAZ-containing satellites were the major source of orbital contamination for satellites that sensed
235:
reactors. The smaller droplets have already decayed/reentered, but larger droplets (up to 5.5 cm in diameter) are still in orbit. Since the metal coolant was exposed to
185:. The primary system failed to eject the reactor core into storage orbit, but the backup managed to push it into an orbit 80 km (50 mi) below its intended altitude.
1296:
99:
due to drag through the upper atmosphere. Further, the satellite would have been useless in the shadow of Earth. Hence the majority of the satellites carried type
1387:
1248:
Wiedemann, C.; Oswald, M.; Stabroth, S.; Klinkrad, H.; Vörsmann, P. (2005). "Size distribution of NaK droplets released during RORSAT reactor core ejection".
153:
Launch failure, 25 April 1973. Launch failed and the reactor fell into the
Pacific Ocean north of Japan. Radiation was detected by US air sampling airplanes.
1402:
182:
1222:
1121:
Wiedemann, C.; Oswald, M.; Stabroth, S.; Klinkrad, H.; Vörsmann, P. (2005). "Modeling of RORSAT NaK droplets for the MASTER 2005 upgrade".
156:
254:
121:
types with a capacity of providing about two kilowatts of power for the radar unit. In addition, in 1987 the
Soviets launched two larger
1349:
138:
253:
An additional mechanism is through the impact of space debris hitting intact contained coolant loops. A number of these
1337:
194:
Although most nuclear cores were successfully ejected into higher orbits, their orbits will still eventually decay.
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221:
72:
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122:
111:
1297:"Effects of the RORSAT NaK Drops on the Long Term Evolution of the Space Debris Population"
1257:
1130:
267:
There were 38 Rorsat satellite launches from
Baikonur, all with reported mass of 3,800 kg.
117:
The US-A programme was responsible for orbiting a total of 33 nuclear reactors, 31 of them
17:
159:(04564 / 1970-079A), 3 October 1970, failed 110 hours after launch, moved to higher orbit.
8:
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1350:"Havoc in the Heavens: Soviet-Era Satellite's Leaky Reactor's Lethal Legacy"
198:
95:. Had they used large solar panels for power, the orbit would have rapidly
69:
1099:, an experimental nuclear reactor launched into orbit by the United States
1282:
C. Wiedemann et al, "Size distribution of NaK droplets for MASTER-2009",
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107:
1223:"Spy Satellite Reactor Now in a Safe Orbit, Its Trackers Report"
231:, respectively) escaped from the primary coolant systems of the
1338:
Encyclopedia
Astronautica article on the US-A RORSAT programme.
1247:
1120:
224:
209:
During 16 reactor core ejections, approximately 128 kg of
166:
240:
232:
118:
100:
80:
76:
1284:
Proceedings of the 5th
European Conference on Space Debris
1196:
David. S.F. Portree; Joseph P. Loftus Jr. (January 1999).
210:
258:
become a significant source of space debris themselves.
144:
The last US-A satellite was launched 14 March 1988.
1286:, 30 March-2 April 2009, (ESA SP-672, July 2009).
1379:
1343:The US-A program and radio observations thereof
1367:"Old Nuclear-Powered Soviet Satellite Acts Up"
1162:"Summary of space-based nuclear power systems"
1388:Reconnaissance satellites of the Soviet Union
1364:
1347:
23:Soviet nuclear-powered surveillance satellite
1276:
1241:
1159:
75:. Launched between 1967 and 1988 to monitor
137:for astronomical and security purposes, as
262:
1191:
1189:
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239:radiation, it contains some radioactive
27:
197:US-A satellites were a major source of
1403:Nuclear technology in the Soviet Union
1380:
1186:
139:radioisotope thermoelectric generators
125:(six kilowatts) in Kosmos satellites (
52:for Controlled Active Satellite), or
58:Radar Ocean Reconnaissance Satellite
13:
205:. The debris is created two ways:
14:
1414:
1365:Leonard David (15 January 2009).
1331:
189:
83:, the satellites were powered by
1160:Regina Hagen (8 November 1998).
1348:Leonard David (29 March 2004).
1143:10.1016/j.actaastro.2005.03.014
1302:
1215:
1175:
1153:
1:
1182:positron pollution from TOPAZ
1113:
1198:Orbital Debris: A Chronology
147:
68:17F16K), was a series of 33
56:, also known in the west as
50:Управляемый Спутник Активный
37:Upravlyaemy Sputnik Aktivnyy
7:
1299:, University of Pisa, 1997.
1090:
79:and merchant vessels using
10:
1419:
1250:Advances in Space Research
271:Rorsat satellite launches
15:
1270:10.1016/j.asr.2005.05.056
1108:List of Kosmos satellites
73:reconnaissance satellites
49:
263:List of US-A satellites
1398:Nuclear power in space
123:TOPAZ nuclear reactors
33:
171:Northwest Territories
31:
18:USA (disambiguation)
16:For other uses, see
1262:2005AdSpR..35.1290W
1135:2005AcAau..57..478W
272:
1227:The New York Times
671:1977 September 18
648:1977 September 16
291:Inclination (deg)
270:
112:Earth's atmosphere
34:
1123:Acta Astronautica
1103:Space-based radar
1088:
1087:
1020:1987 December 12
579:1975 December 12
464:1973 December 27
395:1971 December 25
1410:
1374:
1361:
1360:on 5 April 2004.
1356:. Archived from
1325:
1324:
1322:
1320:
1306:
1300:
1295:A. Rossi et al,
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1256:(7): 1290–1295.
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1229:. 5 October 1988
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1129:(2–8): 478–489.
905:1984 October 31
625:1976 October 21
602:1976 October 17
327:US-A Mass Model
324:1969 January 25
273:
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104:nuclear reactors
85:nuclear reactors
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951:1985 August 23
859:1982 October 2
788:1982 August 30
742:1981 August 24
418:1972 August 21
347:1970 October 3
282:Launch Vehicle
279:Satellite Name
265:
220:of 22% and 78%
203:low Earth orbit
192:
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93:low Earth orbit
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1332:External links
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1203:(Report). NASA
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294:Period (min)
293:
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285:Perigee (km)
284:
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215:fusible alloy
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1393:Space radars
1370:
1358:the original
1353:
1317:. Retrieved
1313:
1304:
1291:
1283:
1278:
1253:
1249:
1243:
1231:. Retrieved
1226:
1217:
1205:. Retrieved
1177:
1165:. Retrieved
1155:
1126:
1122:
1069:Cosmos 1932
1046:Cosmos 1860
1023:Cosmos 1900
1000:Cosmos 1736
977:Cosmos 1771
954:Cosmos 1677
931:Cosmos 1670
908:Cosmos 1607
885:Cosmos 1579
862:Cosmos 1412
839:Cosmos 1365
836:1982 May 14
816:Cosmos 1372
813:1982 June 1
768:Cosmos 1249
745:Cosmos 1299
722:Cosmos 1266
699:Cosmos 1176
510:1974 May 17
487:1974 May 15
288:Apogee (km)
276:Launch Date
266:
243:-39, with a
199:space debris
196:
193:
143:
116:
89:
61:
57:
53:
36:
35:
25:
792:Cosmos 1402
651:Cosmos 952
628:Cosmos 861
605:Cosmos 860
582:Cosmos 785
559:Cosmos 724
536:Cosmos 723
513:Cosmos 654
490:Cosmos 651
467:Cosmos 626
421:Cosmos 516
398:Cosmos 469
375:Cosmos 402
350:Cosmos 367
302:Cosmos 209
248:satellites.
183:Kosmos 1900
177:Kosmos 1402
131:Kosmos 1867
127:Kosmos 1818
108:uranium-235
106:fuelled by
1382:Categories
1319:31 October
1114:References
1072:Tsyklon 2
1049:Tsyklon 2
1026:Tsyklon 2
1003:Tsyklon 2
980:Tsyklon 2
957:Tsyklon 2
934:Tsyklon 2
911:Tsyklon 2
888:Tsyklon 2
865:Tsyklon 2
842:Tsyklon 2
819:Tsyklon 2
796:Tsyklon 2
771:Tsyklon 2
748:Tsyklon 2
725:Tsyklon 2
702:Tsyklon 2
679:Tsyklon 2
675:Cosmos 954
654:Tsyklon 2
631:Tsyklon 2
608:Tsyklon 2
585:Tsyklon 2
562:Tsyklon 2
539:Tsyklon 2
516:Tsyklon 2
493:Tsyklon 2
470:Tsyklon 2
447:Tsyklon 2
424:Tsyklon 2
401:Tsyklon 2
378:Tsyklon 2
163:Kosmos 954
157:Kosmos 367
135:gamma-rays
66:GRAU index
1371:Space.com
1354:Space.com
354:Tsyklon 2
245:half-life
229:potassium
148:Incidents
42:‹See Tfd›
1233:19 March
1207:19 March
1167:19 March
1097:SNAP-10A
1091:See also
444:failure
330:Tsyklon
218:eutectic
1258:Bibcode
1131:Bibcode
1084:104.40
1061:104.00
1015:104.40
992:104.20
969:103.90
946:104.10
923:104.10
900:103.90
877:103.90
854:103.60
831:103.90
783:103.90
760:103.90
737:103.60
714:103.40
666:104.10
643:104.20
620:104.30
597:104.20
574:102.90
551:103.60
528:104.40
505:103.40
482:103.90
436:104.50
413:104.60
390:104.90
367:104.50
319:103.00
306:Tsyklon
237:neutron
213:-78 (a
97:decayed
46:Russian
1310:"US-A"
1081:65.10
1078:1,008
1058:65.00
1038:99.10
1035:66.10
1012:65.00
989:65.00
986:1,000
966:64.70
963:1,001
943:64.90
940:1,007
920:65.00
897:65.10
874:64.80
851:65.10
828:64.90
808:89.60
805:65.00
780:65.00
757:65.10
734:64.80
711:64.80
691:89.70
688:65.00
663:64.90
640:64.90
617:64.70
594:65.10
591:1,004
571:65.60
548:64.70
525:64.90
522:1,006
502:65.00
479:65.40
433:64.80
430:1,038
410:64.50
407:1,006
387:65.00
384:1,011
364:65.30
361:1,022
316:65.30
225:sodium
167:Canada
70:Soviet
62:RORSAT
32:RORSAT
1201:(PDF)
241:argon
233:BES-5
119:BES-5
101:BES-5
81:radar
1321:2023
1235:2023
1209:2023
1169:2023
1075:920
1055:992
1052:900
1032:735
1029:696
1009:995
1006:936
983:909
960:880
937:893
917:994
914:908
894:970
891:914
871:998
868:886
848:979
845:881
825:966
822:919
802:266
799:250
777:976
774:904
754:962
751:926
731:941
728:911
708:962
705:873
685:265
682:251
660:990
657:911
637:987
634:928
614:995
611:923
588:907
568:943
565:852
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