Proba-3 achieves precise formation flying

For the first time, two spacecraft in orbit were aligned in formation with millimetre precision and maintained their relative position for several hours without any control from the ground.

The Proba-3 mission is led by ESA and put together by a consortium managed by Spain’s Sener, with participation of more than 29 companies from 14 countries and with key contributions from GMV and Airbus Defence and Space in Spain and Redwire Space and Spacebel in Belgium.

The coronagraph instrument comes from Belgium’s Centre Spatial de Liège (CSL) and the science data will be processed by the Royal Observatory of Belgium. The mission was launched on 5 December 2024 on a PSLV-XL launcher from Satish Dhawan Space Centre in Sriharikota, India.

Proba-3 orbit

The ultimate goal is for the two spacecraft to align with the Sun so that the 1.4-m large disc carried by the Occulter casts a 5-cm shadow onto the optical instrument on the Coronagraph, allowing it to study the faint solar corona.

Teodor Bozhanov, formation flying system engineer, explains further: “The initiation of this formation-flying repetitive sequence is performed by the ground control centre, with the operations team obtaining position information to determine the exact location of the two satellites in space. The mission’s thrusters are then used to bring them closer together.

“All the rest is done autonomously. The spacecraft measure and control their relative position using the Visual Based System, which includes a wide-angle camera on the Occulter tracking a set of flashing LED lights on the Coronagraph.

Proba-3 mission team in the ESEC control room

The ultimate goal is for the two spacecraft to align with the Sun so that the 1.4-m large disc carried by the Occulter casts a 5-cm shadow onto the optical instrument on the Coronagraph, allowing it to study the faint solar corona.

Teodor Bozhanov, formation flying system engineer, explains further: “The initiation of this formation-flying repetitive sequence is performed by the ground control centre, with the operations team obtaining position information to determine the exact location of the two satellites in space. The mission’s thrusters are then used to bring them closer together.

“All the rest is done autonomously. The spacecraft measure and control their relative position using the Visual Based System, which includes a wide-angle camera on the Occulter tracking a set of flashing LED lights on the Coronagraph.

Proba-3 infographic: Lining up with the Sun

The ultimate goal is for the two spacecraft to align with the Sun so that the 1.4-m large disc carried by the Occulter casts a 5-cm shadow onto the optical instrument on the Coronagraph, allowing it to study the faint solar corona.

Teodor Bozhanov, formation flying system engineer, explains further: “The initiation of this formation-flying repetitive sequence is performed by the ground control centre, with the operations team obtaining position information to determine the exact location of the two satellites in space. The mission’s thrusters are then used to bring them closer together.

“All the rest is done autonomously. The spacecraft measure and control their relative position using the Visual Based System, which includes a wide-angle camera on the Occulter tracking a set of flashing LED lights on the Coronagraph.

Proba-3’s orbit

The Proba-3 mission is led by ESA and put together by a consortium managed by Spain’s Sener, with participation of more than 29 companies from 14 countries and with key contributions from GMV and Airbus Defence and Space in Spain and Redwire Space and Spacebel in Belgium.

The coronagraph instrument comes from Belgium’s Centre Spatial de Liège (CSL) and the science data will be processed by the Royal Observatory of Belgium. The mission was launched on 5 December 2024 on a PSLV-XL launcher from Satish Dhawan Space Centre in Sriharikota, India.

Proba-3 infographic: Spacecraft

The ultimate goal is for the two spacecraft to align with the Sun so that the 1.4-m large disc carried by the Occulter casts a 5-cm shadow onto the optical instrument on the Coronagraph, allowing it to study the faint solar corona.

Teodor Bozhanov, formation flying system engineer, explains further: “The initiation of this formation-flying repetitive sequence is performed by the ground control centre, with the operations team obtaining position information to determine the exact location of the two satellites in space. The mission’s thrusters are then used to bring them closer together.

“All the rest is done autonomously. The spacecraft measure and control their relative position using the Visual Based System, which includes a wide-angle camera on the Occulter tracking a set of flashing LED lights on the Coronagraph.

The Proba-3 mission is led by ESA and put together by a consortium managed by Spain’s Sener, with participation of more than 29 companies from 14 countries and with key contributions from GMV and Airbus Defence and Space in Spain and Redwire Space and Spacebel in Belgium.

The coronagraph instrument comes from Belgium’s Centre Spatial de Liège (CSL) and the science data will be processed by the Royal Observatory of Belgium. The mission was launched on 5 December 2024 on a PSLV-XL launcher from Satish Dhawan Space Centre in Sriharikota, India.

Proba-3’s journey to see the Sun’s corona

Proba-3 achieves precise formation flying

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