Solar panels for space applications: leading players in the success of every mission

15 June 2021

Leonardo has always been committed to space, investing in research to produce solar panels as indispensable elements for the supply of energy to satellites and spacecraft, regardless of their mission. This sector and market are enjoying exponential growth, and today Leonardo is a leading player worldwide.

Space Rider

A notable recent success is the Space Rider programme, launched by the European Space Agency (ESA) in December 2020, for the construction – with Italy as the main investor – of an uncrewed, reusable, robotic spaceplane. Currently being designed, Space Rider will have a total mass of 2.4 tons and the capacity to carry a payload of 800 kg, with a maximum volume of 1,200 litres. The system is the continuation of the Intermediate eXperimental Vehicle (IXV) experience, developed to verify the ability to carry out controlled descent from Low Earth Orbit (LEO).

Space Rider’s launch has taken five years to prepare, but will be ready for its debut in 2023, participating in a wide variety of missions, such as LEO experiments, Earth observation (EO) and satellite inspections.

Italy’s contribution includes:

  • Manufacturing activities and qualification of the flight segment, entrusted to Thales Alenia Space (a Thales 67% and Leonardo 33% joint venture) and Avio
  • The ground control system, supplied by Telespazio (a Leonardo 67% and Thales 33% joint venture) and Altec
  • The electrical system – starting with the solar panels – of the reusable spaceplane, entrusted to Leonardo.

For years, Leonardo's solar panels have been contributing to powering satellites on important space missions, including the Italian COSMO-SkyMed and PRISMA satellites, the European Rosetta mission (which lasted a year and involved comet 67P), ExoMars, MetOp-SG (MetOp Second Generation, a family of weather satellites jointly developed by ESA and EUMETSAT), and the Copernicus EO constellation (Sentinel-3, Sentinel 5-P and Sentinel-6).

Particularly significant in this context is the configuration for the MetOP-SG and Sentinel-6 satellites, in which the layout of the solar panels changes according to the mission being carried out, the type of orbit and the different services that the satellites must guarantee over time.

Building the largest ever solar panel surface for interplanetary probes and satellites

Leonardo also plays a decisive role in the demanding JUICE (Jupiter Icy Moon Explorer) mission, the first on a large scale within ESA’s Cosmic Vision 2015-2025 planetary exploration programme. The probe will be launched in 2022, arriving near Jupiter in 2029 to conduct detailed observations of the planet and of three of its largest moons: Ganymede, Callisto and Europa.

Power will be guaranteed by 10 solar panels, for a total area of about 85m2 – the largest solar panel surface ever built for interplanetary probes and satellites. Each panel will measure 2.5 x 3.5 metres and will consist of 2,356 solar cells joined together in a honeycomb layout and arranged on a carbon fibre reinforced structure. The two solar wings will each comprise five panels laid out in a characteristic cross shape. They will need to fold completely in order to be transported inside the launcher, and be connected to the elaborate deployment mechanism that will allow them to open as soon as the satellite reaches orbit. In addition to aspects relating to the size and complexity of the system, another design issue is the operating environment, which, being very far from the sun, will have very low temperatures.

Continuous innovation

These difficulties pose a great challenge for Leonardo to develop technologies for the design of solar panels and maintain its leadership in this field. Naturally, every project has its own special features and specifications dictated by the final goal. Unlike commercial applications where standardisation can lead to economies of scale, systems for scientific missions are unique and therefore generally require an ad hoc design.

And yet there is one aspect common to all space applications; the need to develop solar panels that are increasingly light, efficient and modular, and can be arranged in arrays of different shapes and sizes.

To this end, Leonardo is researching the creation of flexible, roll-up panels, alongside studies on materials and on models to improve the efficiency of the W/m2 ratio. At the same time, Leonardo is working on expanding its capacities in this sector so as to supply not just solar panels by entire systems, inclusive of the solar array, the deployment system, and the power control and distribution unit. The company already has some of the necessary capabilities, and space programmes such as Space Rider will certainly help to develop them further.

Leonardo has also embraced the concept of Industry 4.0, engaging in the automation, standardisation and progressive development of Artificial Intelligence elements for energy management onboard space objects such as satellites, probes and spacecraft.