Xenon Very High Temperature Resistojet (VHTR)

The trend in telecommunication satellites is to use xenon electric propulsion systems to perform orbit raising and station keeping functions. Due to the low thrust of levels of these systems, there is a need to embark auxiliary systems (convetionally based on chemical propulsion) to perform rate dumping and safe mode manoeuvres. The xenon VHTR allows to efficiently replace chemical propulsion systems hence raising the possibility of improving the system performance while reducing its overall complexity and costs.

The use of the VHTR offers a more cost-effective solution thanks to the possibility of sharing the propellant, tank and propellant feed system with the main electric propulsion engine. The VHTR can be easily integrated into an all-electric propulsion system design and brings advantages in terms of the overall system and with respect to the performance of other thrusters, i.e. cold gas.

In the frame of an ESA project Mars Space Ltd is developing the xenon VHTR in partnership with Nammo (formerly Moog) and with the support of Airbus and ATL. The VHTR has to deliver a specific impulse of about 100s, almost twice that of conventional xenon resistojet, and a thrust of the order of hundreds of millinewton with an efficiency of about 50%.

Typical performance characteristics are:

  • Operating media: GXe, GKr, GAr, GN2
  • Total Impulse: >10 kNs
  • Thrust: 200 mN with xenon
  • Isp: >80 s with xenon
  • Efficiency: ~50% with xenon
  • Mass: <250 g
  • Dimensions: about 30 mm (outside diameter) x 100 mm (length)