This electronic version (PDF) was scanned by the International Telecommunication Union (ITU) Library & Archives Service from an original paper document in the ITU Library & Archives collections. La présente version électronique (PDF) a été numérisée par le Service de la bibliothèque et des archives de l'Union internationale des télécommunications (UIT) à partir d'un document papier original des collections de ce service. Esta versión electrónica (PDF) ha sido escaneada por el Servicio de Biblioteca y Archivos de la Unión Internacional de Telecomunicaciones (UIT) a partir de un documento impreso original de las colecciones del Servicio de Biblioteca y Archivos de la UIT. (ITU) ﻟﻼﺗﺼﺎﻻﺕ ﺍﻟﺪﻭﻟﻲ ﺍﻻﺗﺤﺎﺩ ﻓﻲ ﻭﺍﻟﻤﺤﻔﻮﻇﺎﺕ ﺍﻟﻤﻜﺘﺒﺔ ﻗﺴﻢ ﺃﺟﺮﺍﻩ ﺍﻟﻀﻮﺋﻲ ﺑﺎﻟﻤﺴﺢ ﺗﺼﻮﻳﺮ ﻧﺘﺎﺝ (PDF) ﺍﻹﻟﻜﺘﺮﻭﻧﻴﺔ ﺍﻟﻨﺴﺨﺔ ﻫﺬﻩ .ﻭﺍﻟﻤﺤﻔﻮﻇﺎﺕ ﺍﻟﻤﻜﺘﺒﺔ ﻗﺴﻢ ﻓﻲ ﺍﻟﻤﺘﻮﻓﺮﺓ ﺍﻟﻮﺛﺎﺋﻖ ﺿﻤﻦ ﺃﺻﻠﻴﺔ ﻭﺭﻗﻴﺔ ﻭﺛﻴﻘﺔ ﻣﻦ ﻧﻘﻼ ً◌ 此电子版（PDF版本）由国际电信联盟（ITU）图书馆和档案室利用存于该处的纸质文件扫描提供。 Настоящий электронный вариант (PDF) был подготовлен в библиотечно-архивной службе Международного союза электросвязи путем сканирования исходного документа в бумажной форме из библиотечно-архивной службы МСЭ. © International Telecommunication Union INTERNATIONAL RADIO CONSULTATIVE COMMITTEE C.C.I.R. XHIth PLENARY ASSEMBLY GENEVA, 1974 VOLUME n SPACE RESEARCH AND RADIOASTRONOMY (STUDY GROUP 2) Published by the INTERNATIONAL TELECOMMUNICATION UNION GENEVA, 1975 feuille de route covering note hojas de control secretariat general de I'union internationale des telecommunications • general secretariat international telecommunication union » secretaria general de la union internacional de telecomunicaciones Objet: . Documents de la X H I e A.P. du CCIR, Geneve, 1974 S u b je c t: Documents of the Xlllth P.A. of the CCIR, Geneva, 1974 A s u n to : Documentos de la XIII A.P. del CCIR, Ginebra, 1974 GENEVE, le 20 avril 1977 Place des Nations Corrigendum a la feuille de route de 1 ’Addendum N°1 au volume II de la XIIIe Assemblee pleniere du CCIR, Geneve»1974 Les deux dernieres lignes se lisent ainsi : Question 17/2. Cette Question est reproduite sur la page separee 320 ci-jointe. Corrigendum to the Covering Note of the Addendum No. 1 to Volume II of the X lllth Plenary Assembly of the CCIR, Geneva, 1974 The last two lines to read as follows : Question 17/2 : This Question is reproduced on the separate page 320 attached hereto. Corrigendum a la hoja de control del Addendum N.° 1 al Volumen II de la XIII Asamblea Plenaria del CCIR, Ginebra, 1974 La ultima lfnea debe leerse asf : Cuestion 17/2 . Esta Cuestion figura en la pagina separada 320 adjunta. COVERING NOTE GENERAL SECRETARIAT INTERNATIONAL TELECOMMUNICATION UNION Subject GENEVE, : Documents of the PLACE DES NATIONS X lllth Plenary Assembly o f th e C.C.I.R., Geneva, 197^ ADDENDUM No. 1 to VOLUME I I X lll th PLENARY ASSEMBLY OF THE C.C.I.R Geneva, 197^ Note by the Diveetov3 C.C.I,R, Subsequent to the publication of Volume II (Space research and radioastronomy) of the documents of the X lllth Plenary Assembly of the C.C.I.R., a new text relating to search for extraterrestrial life has been submitted for adoption by correspondence, in conformity with the provisions of No. 308 of the International Telecommunication Convention, Torremolinos, 1973* It has received more than the twenty approvals necessary for its adoption by the Members of the I.T.U. and has therefore become an official Question of the C.C.I.R. The text is as follows: - Question 17/2. This Question is reproduced on the separate pages 320 and 321 attached hereto Union internationals des telecommunications 1211 GENEVE 20 Suisse - Switzerland - Suiza - 320 - QUESTION 17/2 RADIOCOMMUNICATION REQUIREMENTS FOR SYSTEMS TO SEARCH FOR EXTRATERRESTRIAL LIFE (1976) The C.C.I.R., CONSIDERING (a) that many scientists believe intelligent life to be common in our galaxy; (b) that electromagnetic waves are presently the only practical means of detecting the existence of intelligent extraterrestrial life; (c) that it is believed to be technically possible to receive radio signals from extraterrestrial civilizations; (d) that, although it is not possible to know the characteristics nor to predict the time or duration of these sig­ nals in advance, it is reasonable to believe that artificial signals will be recognizable; '(e) that, while an artificial radio signal of extraterrestrial origin may be transmitted at any frequency, it is technologically impractical to search the entire radio spectrum but the band searched should be sufficiently wide to make detection of a signal reasonably probable; (f) that technological and natural factors which are dependent on frequency determine our ability to receive weak radio signals; (g) that while the search for radio signals from extraterrestrial civilizations has already begun, more sensitive systems will be in use by the 1980’s which could receive harmfufinterference from very weak man-made signals; (h) that it is necessary to share the bands in which the search is conducted with other Services; (j) that available technology will allow a search for these signals from the earth, from earth-orbit, and, even­ tually, from the moon and to minimize interference, certain locations on earth and in space may be preferred; decides that the following question should be studied: 1. what are the most probable characteristics of radio signals which might be broadcast by extraterrestrial civilizations and the technical characteristics and requirements of a system to search for them; 2. what are the preferred frequency bands to be searched and the criteria from which they are determined; 3. what protection is necessary for receiving systems conducting a search for artificial radio signals of extraterrestrial origin; ✓ 4. what criteria will make operation of a search system feasible in shared, adjacent and harmonically related bands of other Services; 5. what is the optimum search method; 6. what are the preferred locations, on earth and in space, for a search system? Addendum No. 1 to Volume II, Xlllth P.A. of the C.C.I.R., Geneva, 1974 INTERNATIONAL RADIO CONSULTATIVE COMMITTEE C.C.I.R. Xlllth PLENARY ASSEMBLY GENEVA, 1974 VOLUME II SPACE RESEARCH AND RADIOASTRONOMY (STUDY GROUP 2) Published by the INTERNATIONAL TELECOMMUNICATION UNION GENEVA, 1975 ISBN 92-61-00031-2 PAGE INTENTIONALLY LEFT BLANK PAGE LAISSEE EN BLANC INTENTIONNELLEMENT RECOMMENDATIONS AND REPORTS 2A Space research SPACE RESEARCH 2B Exploration satellites AND RADIOASTRONOMY 2C Radioastronomy and radar astronomy QUESTIONS AND STUDY PROGRAMMES, DECISIONS, RESOLUTIONS AND OPINIONS V (Study Group 2) PAGE INTENTIONALLY LEFT BLANK PAGE LAISSEE EN BLANC INTENTIONNELLEMENT DISTRIBUTION OF TEXTS OF THE Xfflth PLENARY ASSEMBLY OF THE C.C.I.R. IN VOLUMES I TO XIII Volumes I to XIII, Xlllth Plenary Assembly, contain all the valid texts of the C.C.I.R. and succeed those of the Xllth Plenary Assembly, New Delhi, 1970. 1. Recommendations, Reports, Decisions, Resolutions, Opinions 1.1 Numbering o f these texts Recommendations, Reports, Resolutions and Opinions are numbered according to the system in force since the Xth Plenary Assembly. In conformity with the decisions of the Xlth Plenary Assembly, when one of these texts is modified, it retains its number to which is added a dash and a figure indicating how many revisions have been made. For example: Recommendation 253 indicates the original text is still current; Recommendation 253-1 indicates that the current text has been once modified from the original, Recommendation 253-2 indicates that there have been two successive modifications of the original text, and so on. The X lllth Plenary Assembly adopted a new category of texts known as Decisions, by which Study Groups take action, generally of an organizational nature, relative to matters within their own terms of reference, particularly the formation of (Joint) Interim Working Parties (see Resolution 24-3, Volume XIII). Although the Plenary Assembly did adopt in the form of Resolutions a number of texts which fell into the category of Decisions after amendment of Resolution 24-2, these texts are published in the Volumes of the Xlllth Plenary Assembly as Decisions, for practical reasons. When one of these texts is so published, a reference to the Resolution on which the text is based, is given in parenthesis below the title. The tables which follow show only the original numbering of the current texts, without any indi­ cation of successive modifications that may have occurred. For further information about this numbering scheme, please refer to Volume XIII. 1.2 Recommendations Number Volume Number Volume Number Volume 45 VIII 310, 311 V 436 III 48,49 X 313 VI 439 VIII 77 VIII 314 II 441 VIII 80 X 325-334 I 442, 443 I 100 I 335, 336 III 444 IX 106 in 337 I 445 I 139, 140 X 338, 339 III 446 IV 162 h i 341 I 447-450 X 166 x n (c m v ) 342-349 III 451 XII (CMTT) 182 i 352-354 IV 452, 453 V 205 X 355-359 IX 454-456 III 214-216 X 361 VIII 457-460 VII 218, 219 VIII 362-367 II 461 XII (CMV) 224 VIII 368-370 V 462, 463 IX 237 I 371-373 VI 464-466 IV 239 I 374-376 VII 467, 468 X 240 III 377-379 I 469-472 XI 246 III 380-393 IX 473-474 XII (CMTT) 257, 258 VIII 395-406 IX 475-478 VIII 262 X 407-416 X 479 II 265, 266 XI 417-418 XI 480 III 268 IX 419 X, XI 481-484 IV 270 IX 421 XII (CMTT) 485, 486 VII 275, 276 IX 422, 423 VIII 487-496 VIII 283 IX 427-429 VIII 497 IX 289, 290 IX 430, 431 XII (CMV) 498, 499 X 302 IX 433 I 500, 501 XI 305, 306 IX 434, 435 VI 502-505 XII (CMTT) — 6 — 1.3 Reports Number Volume Number Volume Number Volume 19 III 275-282 I 424-426 V 32 X 283-289