European Space Agency

Modular Top Floor Antenna


The main objective is to obtain a robust design concept for the main structure of the Top Floor. This concept should be adequate to support different antenna lay-out (in terms of antenna number or configurations) with minimum modifications.
The robustness of this design should be reached at the same time as others important objectives:
  • Optimized mass: Assumed an antenna arrangement of two fixed 1.1m Gregorian plus one steerable 1.0m Single offset antenna, total mass is limited to 95 Kg.
  • Stiffness: First mode higher than 35 Hz.
  • Strength: The structural design shall be able to withstand an envelope of the maximum environments specified by the most relevant primes.

Analysed three-antennas design

click for larger image


 This development program has some interesting and challenging aspects:

  • Mitigate risks in TFAA structure when steerable reflector (load in cantilever).
  • To obtain a stable design in front thermal loads to provide good TED performances of the antennas.

To find an innovative design able to be adapted to several configurations through non dramatic changes in the structure.


 The most remarkable benefits of the current design are highlighted below:

  • Modular concept adaptable with minimum changes to different configurations.
  • Possibility to board several missions in a common structure with a single qualification process.
  • ITAR free design.
  • Easy assembly process with the corresponding cost and time savings.
  • Good mechanical performances with low mass.

Generation of an industrial dossier to be used systematically for all the products as basic design dossier.


The Modular Top Floor Antenna Assembly provides a common support for an increasing number of antennas (including reflectors, feeders and sub-reflectors).

The main supporting structure is made by the following sub-assemblies: 

o    Interface ring and raising cylinder
o    Intermediate platform
o    Struts
o    Upper mast
o    Interfaces for Feed Chain Assemblies and their waveguides
o    Upper platform for sub-reflector support
 Considered three-antennas design

This design is an important step forward on the ECE Top Floor Antennas experience. However, the main material and processes technologies proposed for this design are based in the ECE heritage with the carbon fibre structures.


 The full development is split in two phases:

  • Phase I: Dedicated to fix the requirement and to obtain a preliminary analysis and design as well as to manufacture a demonstrator of the lower part of the structure. The phase I activities are developed in the frame of the ARTES 5.2 programme.
Phase I demonstrator
  • Phase II: To drive the preliminary design to a detailed design and to manufacture and Qualification Model. This phase is presented in the frame of the ARTES 3.4 programme.


Current status

 Phase I has been closed by the middle of July 2013. This one is corresponding with Preliminary Design Review Level, but with an advanced stage for both design and analysis. So these results may be considered very confident and according with a mature product.
A demonstrator covering the lower stage of the structure has been manufactured and tested.

Status date

Thursday, December 17, 2015 - 11:34