HPSA High Power Solar Array

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The proposed High Power Solar Array (HPSA) program aims to develop a GaAs Solar Array product family with enhanced performances and competitiveness, fitting with new generation of full electric geostationary satellites (Spacebus NEO).

The aim of the development is to establish full non-recurring (NR) engineering and manufacturing file, allowing to start application programs with a minimum NR effort, thanks to a strong will to propose only "off-the shelf" product, with no customization but with options and modularity to adapt the power needs to the payload mission.

The development activities can be sorted in several domains: 

  • Wings Design & Justification File (till CDR level of maturity)
    • Electrical Architecture
    • Mechanical Architecture
  • Network Qualification (Cell, Solar Cell Assembly (SCA), PhotoVoltaic Assembly (PVA))
  • Mechanical Qualifications (Hinges)
  • Solar Array – System interfaces specifications & compatibility verification
  • PFM Tests Sequence synthesis on first application program

The key challenges for HPSA project are related to :

  • Network compatibility to the requested environment (standard challenge for new network development, mitigated by the use of sub-contractors experience on elementary parts)
  • Mechanical compatibility with new interfaces and environment.
  • Electrical Orbit Raising environment (Radiation, ATOX, Airdrag …)
  • Generated shock at release, with regard to the platform specification
  • New mechanisms (Root hinge and Lateral hinge) development

The HPSA is the natural continuation of Thales Alenia Space solar array product line developed for geostationary platforms, up to  Spacebus NEO (Full electric propulsion).

Its development achieved the following main drivers :

  • Time-to-market: be on the market for the first commercial launch in 2019.
  • Compliance with system needs: EOR compatibility and about 20 kW Payload EOL
  • Best €/W ratio: at least 15-20% of improvement vs previous generation on the same power range, and more than 25% over 15 kW Payload.
  • Improvement of W/Kg vs. previous generation

The HPSA design proposes different wings configuration in terms of quantity of panels and size of panel : one large (L) version and one small (S) version.

Each of these panel size is designed in two generic layout versions (fully equipped / descoped version) pending the amount of strings implemented. 

  • Large Panel (2.2m x 4.2m) : 5 or 6 panels per wing, and 14 to 18 strings per panel
  • Small Panels (2.2m x 3.2m) : 4 to 6 panels per wing, and 9 to 13 strings per panel.

This HPSA product line supports Spacebus NEO power range, from 10.7kW End Of Life to 22.7kW EOL.

System Architecture

The mechanical architecture of the HPSA wing is composed of the following components:

  • The panels substrates with laydown electrical network
  • The yoke (panel concept)
  • The Hinges set for wing deployment
  • The synchronization & sequencer devices for wing deployment
  • The hold down & release structure with low shock release devices

The electrical architecture is tailored according to the spacecraft power need, relying on 15 possible configurations, from 104 to 216 solar cell strings.


The major milestones of HPSA development program are :

  • Kick off meeting in December 2015
  • Critical Design Review closure in December 2017
  • 1st ProtoFlight Model integration starting in November 2018
  • Qualification Review part1 in November 2018
  • 1st Launch in January 2020
  • Full range qualification review in September 2020
Current status


HPSA Product line is fully operational, already on 7 application programs – in 09/2020) - covering the whole family range.
Qualification is completed.

1st application program (Konnect) has been launched in January 2020.

Prime Contractor