Selectable Sub-Reflector Antenna


Satellite operators are pushing for a competitive communication satellite industry. On one hand, they look for rationalizing their fleet and require both price and schedule reduction. On the other hand, to keep market shares, satellite operators call for more reactive and versatile solutions to quickly grasp new markets and to adapt to the short-term evolutions. Satellite industry shall take up the challenge by improving both current telecommunication satellites and offering new generation of satellite technology, more flexible and able to address new markets.

In term of flexibility, there is not a unique antenna solution for all applications. The degree and nature of flexibility within telecommunication satellites nevertheless depends on the final needs. The flexible antenna solutions shall be a compromise between the levels of achievable RF performances flexibility and some other driver parameters like cost, mass, power budget...

This ARTES3-4 project aims to develop an antenna solution keeping the advantages of the “conventional” solutions (antenna RF efficiency, power handling, heritage and risks minimization, cost ,…) and answering at the same time to coverage flexilibity needs in Ku band.


The major concern of the project is the definition of an antenna structure being able to withstand the mechanical launch loads. The product shall be developed with the purpose of being compatible of several platforms, the mechanical solicitations vary from a platform to another and so the antenna shall fulfil the envelope mechanical requirements.

In addition, the re-use of existing rotary actuator without delta qualification imposes to master and optimize the thermal control of the antenna.  


The product developed in the frame of this ARTES3-4 project will complement Thales Alenia Space “in orbit missions flexibility” solutions portfolio with an antenna solution based on conventional technologies and building blocks (CFRP reflectors and structure, feed, rotary actuators) offering high RF performances (large bandwitdth, PIM free, able to work on all Ku band spectrum with a tri-band feed). This new antenna product will help Thales Alenia Space to propose a discriminant antenna solution. 


The Selectable Sub-Reflector antenna is in dual optics Gregorian configuration. The main components of  the antenna are :

  • A Large bandwidth feed (operating in transmit and receive)
  • A CFRP main reflector
  • 4 CFRP sub-reflectors (each one shaped to generate a specified coverage)
  • An Antenna Pointing Mechanism under the antenna for steerability on the whole earth
  • A Selection Line Assembly (sub-system allowing the selection of the desired sub-reflector)
  • Hold Down and Release Mechanisms
  • A CFRP antenna structure 

The antenna is accommodated on the earth panel of the satellite. The main reflector is optimized for all the specified coverages. In both cases, each sub-reflector is optimized for one of the specified coverage.

The reflector technology and most of the antenna components are based on TAS heritage. The Selection Line Assembly is defined to allow the re-use of existing rotary actuator in order to avoid a specific development or a delta qualification. 


The activities of the project are organized according to classical development phases. The main steps of the development are :

-       Requirements consolidation

-       Antenna architecture consolidation (tradeoff between several potential technologies for the antenna structure, the objectives being to define the more competitive solution)

-       Preliminary design and analysis (RF, mechanical, thermal, functional)

-       Detailed design and analysis

-       Manufacturing of the EQM

EQM testing 

Current status


Detailed design and analysis have been done. The antenna EQM has been manufactured and assembled. All the qualification tests have been performed. This qualification test campaign includes :

  • 8 thermal cycles in Nitrogen
  • Acoustic test
  • 3 axis Sine test
  • TED testing
  • TVAC + Life test

All the tests performed are successful. The thermal control defined during analysis phase has been validated. The acoustic test allowed to demonstrate that the rotary actuator used to select the relevant sub-reflector is well suited for SSRA. The sine test performed covers the mechanical loads computed during coupled load analysis. This  confirms the compatibility of this new antenna product with Spacebus platforms.  This ARTES34 project allowed to develop and qualify a new flexible antenna product. This new antenna solution is available for telecom programs


ESA Contacts

Status date

Wednesday, March 22, 2017 - 11:21