ESA’s Proba-3 mission enters the last test phase prior to launch

The Proba-3 mission of the European Space Agency (ESA), led by the Sener engineering and technology group, has reached a new milestone after successfully completing the environmental testing campaign of the two satellites at the IABG facilities in Ottobrunn (Germany). The aim of this testing campaign was to ensure that the satellites and their various devices can withstand the vibrations generated during launch in a stack configuration (with the lighter satellite, ‘Occulter’, atop the ‘Coronagraph’ satellite), and that they will not be affected by the thermal conditions they will experience in orbit, alternating between hot (when the satellites are pointing toward the Sun) and cold (during eclipses).

Rounding out the tests were activation checks of the various mechanisms carried by the satellites (one of which, the solar panel on Coronagraph, was developed by Sener), as well as a complete check of the propulsion systems manufactured by Ariane Group and Bradford.

Having demonstrated the validity of the two Proba-3 platforms, the industrial team led by Sener is now focusing on the last phase of the project: checking the final version of the flight software through functional testing on the satellites and completing operational preparations by using the ground segment tools.

After this last phase, the satellites will be launched in 2024. After the launch and early orbit phase (including separating the stack into two independent satellites), an orbital verification phase will take place prior to delivery to ESA, which will then operate the system for the rest of the mission.

The first time a Spanish company has led the full development of an ESA mission

Sener is spearheading the Proba-3 mission, in close collaboration with an industrial team consisting of Redwire Space, Airbus Defence and Space in Spain, GMV Space and Defence, and Spacebel, which encompasses a large consortium of more than 29 companies from 17 countries. This is the first time that a Spanish company has led the full development of an ESA mission (meaning it is responsible for both the ground and flight segments).

The main goal of the Proba-3 mission is to achieve, for the first time, a high-precision formation flight between two platforms in space. This will demonstrate the feasibility of a technology that will be used in the development of large telescopes whose main elements (such as lenses and detectors) have to be kept far apart while maintaining their relative positions and distances with a high degree of accuracy and stability. This technology will avoid having to resort to heavy and bulky deployable structures, which may not fit onto current rockets, reducing the cost of the launch and operation.

Proba-3 will also conduct a scientific study of the solar corona. The mission’s two satellites (Occulter and Coronagraph) will fly at a distance of 150 metres. They will form what is called a ‘coronograph with an external occulter’, meaning one of the satellites will block the sunlight from entering directly in the camera of the instrument mounted on the other, leaving only the sun’s corona visible. This process will be completely autonomous and create an artificial eclipse on the second satellite lasting six hours every day.

This is a particularly ambitious mission due to, among other reasons, the high degree of autonomy that the on-board algorithms will rely on, and the related operations and coordination required between the two platforms as they move in close proximity in space, aspects whose successful outcome hinges on the tests carried out this summer.

Proba-3 is part of the ESA’s General Support Technology Programme, and Spain’s participation was made possible thanks to the support of the Centre for Technological and Industrial Development.