Hera team uploads software update across 140 million kilometres — spacecraft ready for Dimorphos and Didymos

Successful remote update

The European Space Agency (ESA) has completed a complex software update for the Hera spacecraft from a distance of roughly 140 million kilometres. The update prepares the mission for detailed investigations of the binary asteroid Didymos and its moon Dimorphos in the autumn.

Why the update was necessary

The new software affects core mission functions: navigation, attitude control, autonomous manoeuvres and the operation of scientific instruments, including cameras and radar. Hera will measure up close the consequences of NASA’s 2022 DART impact — including the topography of the impact site, the internal structure and mass of Dimorphos, and changes to its orbit.

Safe implementation in deep space

Remote updates in interplanetary space are delicate: signals need minutes for the round trip, data rates are limited, and a crash must not endanger the spacecraft. The Hera team used staged tests and fallback mechanisms. New modules were initially run in observation mode, telemetry on the ground was checked against emulations, and full activation followed only after positive evaluation. Redundant hardware and software paths, memory and integrity checks, and complete logs minimised risk and keep the option to revert to the previous version if needed.

Scientific goals

Didymos–Dimorphos offers the rare opportunity to directly measure the immediate effects of a controlled impact. Hera will map the impact site at high resolution, use radar to probe porosity and density distribution, and analyse the dynamics of ejected material. Long-term measurements will also show how stable the orbit-changing effects are and how Dimorphos’s orbit evolves. These data are crucial for validating impact physics models.

Importance for planetary defence

While DART demonstrated the principled deflection of a small body, Hera is set to deliver the key quantitative measurements. Together the two missions form the AIDA concept (Asteroid Impact & Deflection Assessment): a targeted intervention followed by precise characterisation. The results will feed into strategies for deflecting potentially hazardous asteroids.

Next steps

Following the successful update, calibrated instrument tests, simulation sequences and final navigation checks will take place in the coming weeks. If everything proceeds as planned, Hera will begin close flybys in the autumn and is expected to return the first datasets on the direct consequences of the DART impact.