HYDRA Star Tracker for Telecom

Status date

The HYDRA TELECOM product is a variant of the already developed and qualified HYDRA baseline product, optimized to address the GEO telecommunication platforms market.

In the frame of the previous CNES contract, the work packages were distributed in 3 phases:

  • Phase 1 : HYDRA TELECOM Preliminary Specifications, which has been concluded by a Specification Review
  • Phase 2 : HYDRA TELECOM Preliminary Design, which has been concluded by a Baseline Design Review
  •  Phase 3 : HYDRA TELECOM Detailed Design, which will be concluded by the Critical Design Review
The objective of the ARTES 3-4 contract was to continue these activities by the following phases:
  • Phase 4 : Complementary studies and manufacturing of the EQM HYDRA TELECOM
  • Phase 5 : Qualification of EQM HYDRA TELECOM

Click here for larger image



Several star tracker products already exists and are more or less optimized to fulfil the main requirements of the GEO telecommunication market, including Sodern SED26 product, but none of these products offers the advantages of the HYDRA multi-heads approach. The advantages of this different architecture are nevertheless major for the customer, amongst which are:
Simplification of optical head implementation on the platform thanks to low power dissipation
Possibility to always operate two active optical heads in normal mode with only one active electronic
Increased robustness of multiple head approach with still possibility to fulfil the mission when only one head available
Better overall reliability of the system thanks to cross strapping between optical heads and electronic units

The huge success of this new HYDRA product architecture in many LEO and even some GEO application is something that can be extended to telecom market assuming the cost is competitive with existing products. Cost optimizations of the product are indeed rather straight forward taking into account some generic requirements for telecom application such as number of optical heads and redundancy. 

The Generic HYDRA product is a new generation of star tracker taking advantage of the state of the art APS detector technology to offer a new multi-head architecture with separated optical head from centralized processing unit. This architecture provides a more robust and more autonomous star tracker product compared to classical single box autonomous star trackers.
The baseline of this product was primarily developed for agile Earth observation satellites in LEO with two electronic units and three active optical heads but could also be easily adapted to several other possible configurations:
From one up to four optical heads including one for cold redundancy
Only one or two for cold redundancy centralized processing units

This modular approach was very convenient to adapt to the various requirements of the LEO and some GEO Earth observation mission, but it is not particularly optimized and competitive for the very specific GEO telecommunication market.

CDR : November 2011

Qualification Review : March 2013  

Current status

Hydra Telecom is a qualified product, for which flight models have already been delivered to the first customer.

Prime Contractor