1、QUESTION ITU-R 221/7*Preferred frequency bands and protection criteria for space research service observations (passive) (1997) The ITU Radiocommunication Assembly, considering a) that there are requirements to use spacecraft to conduct space research service (passive) observations; b) that space re
2、search service (passive) observations may be conducted in the same frequency bands utilized by Earth-based passive observations; c) that presently, protection requirements for space research service (passive) systems have not been determined, decides that the following Question should be studied 1 W
3、hat are the typical technical and operating characteristics of space research service (passive) observation systems? 2 What are the preferred frequency bands for space research service (passive) observations? 3 What are the protection criteria for space research service (passive) observations? further decides 1 that the results of the above studies should be included in (a) Recommendation(s); 2 that the above studies should be completed by 2011. _ *In the year 2009, Radiocommunication Study Group 7 extended the completion date of studies for this Question.
