ECSS-E-50-05A – Radio frequency and modulation (24 January 2003)

This standard has been cancelled and replaced by ECSS-E-ST-50-05C (31 July 2008).


This Standard defines the radio communication techniques used for the transfer of information between spacecraft and Earth stations in both directions, and for the tracking systems used for orbit determination. It includes the following subjects:

  • frequency allocation, assignment and use;
  • requirements on transmitted signals concerning, for example, spectral occupation, RF power levels, protection of other radio services;
  • definition of the permissible modulation methods and parameters;
  • specification of the major technical requirements that are relevant for the interface between spacecraft and Earth stations;
  • operational aspects, such as acquisition;
  • cross-support.

This Standard is applicable to all spacecraft supported by Earth stations 1) and to all controlled Earth stations operating in the space operation, Space Research and Earth Exploration Satellite services as defined in the ITU Radio Regulations.2)

Other space telecommunication services are not covered in this issue.

The requirements specified by this Standard supersede any similar requirements contained in any of the related standards published prior to this issue. Consequently, in the case of conflict this Standard takes precedence.

When viewed from the perspective of a specific project context, the requirements defined in this Standard should be tailored tomatch the genuine requirements of a particular profile and circumstances of a project (see annex G).

NOTE Tailoring is a process by which individual requirements or specifications, standards and related documents are evaluated and made applicable to a specific project, by selection and, in some exceptional cases, modification of existing or addition of new requirements.
[ECSS-M-00-02A, clause 3]

1) This Standard is not applicable for spacecraft supported by data relay satellites.
2) This Standard is not applicable to the Meteorological Satellite service.