ESA’s first stand-alone Deep Space CubeSat signs new phase

ESA’s first ever stand-alone deep space CubeSat mission, the Heliospheric Pioneer for Solar and Interplanetary threats Defence (HENON) reached a new milestone today as the prime contractor Argotec, in Italy, and the European Space Agency kicked off the mission’s final implementation phase.

HENON is now moving into Phase C2D, meaning many of the technical risks identifiedat its Preliminary Design Review have now been resolved, and the mission can move forward to perform the detailed design and engineering model development activities before the planned Critical Design Review in August this year.

Now, the flight model of the CubeSat will be developed and tested before being delivered in its deployment system ready for launch, which is planned for the end of 2026.

“Now we can integrate and connect all of the technologies and the platform equipment together into something called a flatsat to test their functionality and interfaces, and start de-risking it,” explains Roger Walker, ESA’s Technology CubeSats manager.

What will HENON do?

HENON will piggyback onboard the launch of another larger spacecraft to the Sun-Earth Lagrange point 2, before using its own miniature electric propulsion system to fly to a Distant Retrograde Orbit (DRO) in the Sun-Earth system, where it will take space weather observations that will enhance our forecasting capabilities.

Walker clarifies: “The goal is to demonstrate solar storm forecasting capabilities by offering 3-6 hours of advance warning before a major solar storm reaches Earth, which is a considerable improvement compared to the current warning time.”

“When the CubeSat has reached this distant retrograde orbit, it passes upstream of Earth on the sunward side, where it is  ten times nearer the sun compared to a spacecraft in the Lagrange 1 position. Once this more advanced warning capability is demonstrated with HENON, eventually, it could open up a pathway to develop a potential future constellation of four or five of them operating in the DRO to provide a continuous service for solar storm early warnings,” he continues.

What’s on board?

HENON, is funded through the General Support Technology Programme’s Element 3, which supports In Orbit Demonstration (IOD) of new technologies. Like most of these IODs, HENON serves two purposes: pushing the boundaries of space technology while ensuring it serves practical applications.

“HENON is a mission that first and foremost is a technology demonstrator. But it has a little bit of both a technology push combined with an application pull," Walker says. As the first ever CubeSat capable of executing its own independent mission in deep space with large manoeuvres, there have been a lot of challenges from a technology perspective.

Key technologies are now being developed to make the mission possible, mostly also within GSTP, from the electric propulsion system being developed by a Mars Space-led consortium in UK to a brand new miniature X-band space transponder from IMT in Italy.

IMT are also developing a new solar array drive assembly that has also needed to be developed, so that the CubeSat’s solar panels can be rotated to maximise the solar power generated. This will be combined with a new Power Conditioning & Distribution Unit being developed by Argotec to supply power to the electric propulsion and transponder, as well as other onboard units.

Beyond those mentioned above, new miniaturised instrument technologies being demonstrated for the space weather observations include a radiation particle telescope, magnetometer and a Faraday Cup for measuring the solar wind properties.
Many of these companies are also involved in a second GSTP CubeSat In Orbit Demonstration mission planned to launch in 2027, the Lunar Meteoroid Impacts Observer (LUMIO), which will observe meteoroid impacts on the lunar farside.

Technologies and Payloads

• X band Deep space Miniature transponder
  • Developer: IMT (Italy)
  • Development: GSTP (ESA's General Support Technology Programme)
  • Purpose: Deep Space Communication via transponder.
• Solar Array Drive Assembly:
  • Developer: IMT (Italy)
  • Development: GSTP (ESA's General Support Technology Programme)
  • Purpose: Rotates solar arrays to maximize solar power generation for the spacecraft's operations, including electric propulsion and transponder.
• Electric Propulsion and Cold Gas Reaction Control systems:
  • Contributor: Mars Space, UK and other industry partners (Techline, AVS, TWI)
  • Development: GSTP (ESA's General Support Technology Programme)
  • Purpose: To achieve the required deep space maneuvering, especially to reach the distant retrograde orbit, supporting the space weather demonstration.
• ‘Magic’ Magnetometer (Space weather and magnetic field measurements):
  • Provider: Imperial College London (UK)
  • Development: Similar to the magnetometer flown on RADCube (Low Earth Orbit mission).
  • Purpose: Measure the magnetic field in deep space, to enhance space weather predictions.
  • Deployment: Mounted on a 1-meter long boom.
• REPE Payload
  • Provider: & Aboa Space Research Oy (ASRO) and Space Research Laboratory Turku Uni Finland
  • Development: Already flown on board the Aalto-1 3U CubeSat in 2017, it has been further developed
  • Purpose: To measure directional proton and electron fluxes
• Faraday Cup Analyser
  • Developer: Charles University in the Czech Republic
  • Purpose: To take solar wind measurements, including ion vector velocity and ion flux.
• Power Conditioning and Distribution Unit
  • Development: Argotec
  • Purpose: Required to regulate the inputs from the 200 W solar array and distribute power to subsystems.