On 15 October 2026, ESA's Hera spacecraft will ignite its orbit control thrusters for 93 minutes to slow down and match the orbital velocity of the Didymos binary asteroid system. This braking maneuver marks the first step in a series of operations aimed at studying the asteroid system following NASA's DART mission impact in 2022. A second, shorter thruster burn is scheduled for the following week to adjust Hera's trajectory for scientific observations.

The mission's Flight Dynamics team, based at ESA's European Space Operations Centre in Darmstadt, Germany, will oversee these operations. Around 10 engineers per shift from a group of over 50 specialists will manage the mission's navigation and trajectory planning. Their responsibilities include determining Hera's position and velocity, generating telecommands for the spacecraft, and analyzing data from ground stations and onboard instruments.

Flight Dynamics Engineer Michael Mueller stated that the team supports multiple ESA missions, including BepiColombo's approach to Mercury and the upcoming Plato exoplanet observatory. During Hera's cruise phase, the team coordinated a Mars flyby in spring 2025 to adjust the spacecraft's trajectory.

Hera will begin its approach to Didymos with a braking maneuver to align with the asteroid system's orbital velocity. Subsequent phases include a 'early characterization' period in November and December 2026, during which Hera will collect baseline data from a distance of 25–30 km. In December, it will move to within 10 km for detailed observations, followed by a 'close observation' phase at 4 km and an experimental phase at 1 km.

The spacecraft will deploy two CubeSats in early 2027 to gather additional data. These CubeSats will be monitored by a separate Flight Dynamics team in collaboration with ESA's CubeSat Mission Operation Centre in Redu, Belgium, and CNES in Toulouse, France.

Hera's navigation relies on radiometric data from ESA's deep space antennas, including signal travel time and Doppler shift to measure range and velocity. The team will also use images from Hera's camera to identify surface features for autonomous tracking.

The exact state of Dimorphos, the smaller asteroid in the system, remains uncertain following NASA's DART impact in September 2022. The Hera team acknowledges potential surprises, such as debris or tumbling, but emphasizes that their approach will adapt to observed conditions.

The mission represents a technical advancement in autonomous spacecraft navigation, building on lessons from ESA's Rosetta comet mission. Unlike Rosetta, which required ground-based trajectory calculations, Hera will increasingly rely on onboard autonomy as it approaches the asteroid system.