Development of the PPU NG HKISEQ Module - Development of the Power Processing Unit (PPU) NG Heater-Keeper-Ignitor Sequencer (HKISeq Module)

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Today, it is confirmed that an extended use of electrical propulsion is envisaged not only to perform Station Keeping Manoeuvers, but also for Electric Orbit-Raising.

Full-electric satellites have already been requested by European sat-coms operators. Airbus Defence and Space is already offering a full-electric version of its successful Eurostar 3000 platform, the so-called Eurostar 3000 New Generation Platform (NGP).

In this way, Airbus Defence and Space Crisa started the development of a New Generation of a modular Power Processing Unit (PPU NG) for both Station Keeping and Electric Orbit-Raising maneuvers.

The PPU NG architecture allows for an optimized distribution of the functions minimizing the number of boards and interconnections among them.

Crisa participates in the PPU NG by developing the HKISeq Module, which is in charge of the thruster’s power supplies, communications with platform and management and control of the full PPU NG as well as HETs connected to the module.


PPUNG is a fully scalable and modular product with capability from 5 to 20kW, able to supply different thrusters. Successful coupling test have been passed with SPT-140 and PPS5000 Hall Effect Thrusters and possibilities to be integrated in different platforms as E3000 and NEOSAT.


The PPU NG architecture allows for an optimized distribution of the functions minimizing the number of boards and interconnections among them thanks to the HKISeq Module architecture.

The PPU NG can provide from 5kW to 20kW units and with capability to drive to 6 HET; i.e. 4 thrusters in full power. According satellite platform needs and organization, these modules could be fully integrated or distributed on the satellite. PPU NG is considered as new equipment so it falls in class A equipment. The target missions are those equipped with a 100V regulated bus as HET technologies.

HKISEQ Module and its accommodation into the PPUNG

Another important feature about the HKISeq module is its design-to-cost approach allowing an attractive recurring price. Moreover, HKISEQ Module uses innovative winding solutions in magnetics to withstand required high-voltage conditions. 


Main features of the HKISeq Module are:

  • Compatibility with regulated 100V input bus
  • Compatibility with different HET Cathodes and dedicated firing of the thruster by the appropriate sequencing of the power supplies towards the thruster (up to the 6 thrusters to be fired)
  • Two communication protocols with the platform and other modules in the PPU NG
  • European PPU.
  • Modular design.
  • Readily scalable to large satellites and very high power levels (5kW to 20kW).
  • Compatible with Eurostar 3000 and Neosat Platforms


System Architecture

The HKISeq module provides all the necessary resources required by the thruster during the start-up and control functionalities of the overall PPU NG. The modularity and packaging concept relies on 3 different sub-modules in order to insure a maximum segregation between the platform and the thruster, where high voltage and noisy signals are produced. The general architecture, including sub-modules, is shown on the following figure.

  • Platform Electronics
  • Cathode Electronics
  • FCSU (Filter Cathode Selection Unit)

This way all the electronics associated to different grounds are in different PCBs making the HKISeq less susceptible to noise as different grounds are physically segregated.


The Artes 3-4 HKISeq Module development logic is split up in several phases to be in line with the Artes 3-4 project. These phases are:

  • PHASE 0: HKISeq Module Definition phase up to Artes 3-4 KO
  • PHASE 1: HKISeq Module Preliminary Design phase up to Artes 3-4 PDR
  • PHASE 2: HKISeq Module Detailed Design Review phase up to Artes 3-4 CDR
  • PHASE 3: HKISeq Module EQM manufacturing and acceptance testing phase up to Artes 3-4 TRR and FR.
Current status

PPUNG, including HKISEQ, has successfully passed the EQM Qualification campaign. The project is completed.