In an account published October 7, 2026, the European Space Agency (ESA) said Hera’s first braking maneuver, BRM-1, was scheduled for October 15. The continuous 93-minute burn is intended to reduce Hera’s velocity relative to the Didymos system by a few hundred meters per second, setting up the spacecraft’s planned asteroid observations.
Hera’s planned braking maneuver
Hera is approaching Didymos and its moon Dimorphos. ESA’s plan calls for three hydrazine-based Orbit Control Thrusters to fire continuously during BRM-1; Reaction Control Thrusters are intended to help keep the spacecraft correctly oriented. The maneuver’s purpose is to reduce Hera’s speed relative to the asteroid system.
ESA also described a brief test burn on October 2 before preparation of the full command sequence. Its schedule called for BRM-2 on October 22, as a planned follow-up lasting about 31 minutes. That burn is intended to complete most of the velocity adjustment and compensate for any shortfall in BRM-1.
What ESA says BRM-1 and BRM-2 will do
The two burns have distinct roles: BRM-1 is intended to make the initial reduction in relative velocity, while BRM-2 is planned to complete most of the adjustment. ESA describes the BRM-1 target as “a few hundred meters per second,” rather than specifying a more exact change.
How ESA will track Hera and assess the burn
ESA’s Flight Dynamics team plans to combine spacecraft telemetry and guidance, navigation and control (GNC) sensor data with radio ranging and Doppler measurements. Ranging helps estimate distance; Doppler shifts in the signal help determine motion. After BRM-1, those inputs are intended to help the team assess the direction and size of the velocity change.
As Hera gets closer, images from its onboard camera are also expected to help refine estimates of the spacecraft’s orbit and the Didymos system’s state, including the relative orbit and rotation of Didymos and Dimorphos. ESA says six teams will examine incoming data, including through independent checks. Around 10 people work each shift on Hera-related flight-dynamics tasks, drawn from a team of more than 50; preparing detailed operational material can take 10 hours of work at a time.
The next planned stages of Hera’s approach
ESA’s planned sequence moves from early characterization 25–30 kilometers from the asteroid system to detailed characterization at 10 kilometers. Later close observations are planned as near as 4 kilometers, followed by an experimental phase 1 kilometer from Dimorphos. ESA also plans to deploy two CubeSats from Hera.
The mission will examine the aftermath of NASA’s DART spacecraft deliberately striking Dimorphos on September 26, 2022. ESA says the moon’s post-impact state—including how much it tumbles and whether debris remains nearby—is still uncertain.
