Today, 18 February 2025, the Solar Orbiter spacecraft will perform a close flyby of Venus – one of a series of planetary flybys that is being used to change its orbit to enable scientists to study the Sun’s poles for the first time.
Starion’s space engineers are contributing to the mission in a number of ways, including supporting planning for the flyby through their work on SPICE software operations and the Cosmographia visualisation tool.
Solar Orbiter’s flyby of Venus on 18 February 2025 as visualised by the Cosmographia app using SPICE data.
Tilting Solar Orbiter’s orbit to view the Sun’s poles
Later today, Solar Orbiter will make its fourth gravity assist flyby of Venus, passing closer to Venus than ever before at less than 400km above the planet’s surface. Although Solar Orbiter’s primary mission is to study the Sun, scientists have used planning tools supported by Starion’s space engineers – in particular the SPICE service and Cosmographia – to set up its instruments to observe Venus’s magnetosphere and plasma environment during the flyby.
Launched in February 2020, Solar Orbiter’s initial flybys of Venus and Earth were designed to place it into its required orbit, while the later flybys are gradually tilting its orbit so that its instruments can view the solar poles. This flyby will increase its inclination from around 7.7 to 17 degrees out of the ecliptic plane, providing the first glimpse of the Sun’s polar regions, with further flybys set to increase its inclination to around 33 degrees.
Careful planning for each flyby is vital, not only to ensure the orbit changes as planned, but also to allow scientists to understand what will be in the view of each of the 10 instruments at any time. This is where SPICE comes in. The SPICE team at the European Space Astronomy Centre (ESAC) in Spain, led by Starion’s Alfredo Escalante Lopez, European Space Agency (ESA) Spice Work Package Manager, receive an array of mission-related data, such as trajectory and attitude predictions, in different formats from multiple sources. These are converted into the SPICE format and distribute for use in tools used to prepare flyby operations and observations.
About SPICE and Cosmographia
SPICE was originally developed in the 1990s by the Navigation and Ancillary Information Facility (NAIF) at NASA’s Jet Propulsion Laboratory (JPL). SPICE now provides the core of planning tools used for all ESA’s planetary missions, including Cosmographia, which also originated from JPL’s NAIF. The SPICE team is responsible for keeping both SPICE data and planning tools such as Cosmographia up to date, and making geometry data for planning and analysing operations available to the science community.
“Cosmographia provides a powerful visual way to view the geometry data for missions such as Solar Orbiter as it holds both ‘flown’ telemetry data downloaded from the spacecraft and ‘planning’ or ‘predicted’ data,” explained Alfredo Escalante Lopez. “This lets users see how the spacecraft’s trajectory will change over time. More importantly, they can also use it to display the field of view of each instrument, which for Solar Orbiter enables them to plan an observation of a specific region of the Sun or, in this case, of Venus. It can also be used to see the position of spacecraft components such as solar arrays and antennas at any time.”
Additional Starion mission support
Spacecraft instruments are carefully designed to tolerate the temperatures and other conditions specific to the particular mission. As Venus is the hottest planet in our solar system, the instruments on spacecraft travelling to the outer planets would not be able to tolerate the heat generated by such a close flyby of Venus. Solar Orbiter’s instruments, however, are designed to withstand much higher temperatures, making them suitable for studying Venus as well as the Sun.
Data from these instruments, and those of the majority of ESA’s astronomy, planetary science and heliophysics missions, are held in the archives at the ESAC Science Data Centre. Starion’s space engineers are part of the team responsible for archiving all this data, along with telemetry data, and making it permanently available to the scientific community, using standard formats, via a web interface and other clients.
Jonathan Cook, Software Engineer at Starion in Spain, said: “Solar Orbiter is a unique mission with its 10 instruments studying the Sun – gathering information about something we see every day and can all relate to. Managing the interface between the archive and so many instruments for one mission is a big challenge, but Solar Orbiter is very important for the scientific community and to be directly involved in it is very rewarding.”
Further information
Would you like to run the Cosmographia app on your own computer to view simulations of ESA’s planetary missions? The SPICE-enhanced Cosmographia tool is freely available for download, along with the required catalogue files for each mission, including Solar Orbiter, at: cosmos.esa.int/web/spice/cosmographia
Solar Orbiter Archive: soar.esac.esa.int/soar/