ESA’s Hera spacecraft has received a critical software upgrade, transmitted across roughly 140 million kilometres of deep space, that activates the systems it will need to navigate around the asteroid moonlet Dimorphos when it arrives this autumn.
The upload, confirmed by the European Space Agency on 8 July 2026, is the culmination of an 18-month test campaign and marks the point at which Hera’s onboard computer switches on the instruments and autonomous-navigation software it will rely on once it reaches the Didymos–Dimorphos binary asteroid system.
Why a software update matters this far from Earth
Uploading new flight software to a spacecraft already in transit is inherently high-risk: commands took roughly eight minutes to reach Hera via ESA’s 35-metre deep-space antennas, and any error can only be diagnosed and corrected after that same round-trip delay. To reduce risk, Hera’s onboard computer runs on redundant parallel processor streams, so engineers uplinked and validated the new software twice — rebooting and testing each processor chain separately before committing to the new build.
ESA describes the ground testing behind the upload as one of the most complex campaigns it has run for a single mission: engineers logged around 50 dedicated test days at the European Space Operations Centre (ESOC) in Darmstadt, using “the Bench,” a functional replica of Hera built by prime contractor OHB in Bremen, to simulate asteroid-proximity operations and the inter-satellite links Hera will use to talk to its two CubeSats, Juventas and Milani.
What the new software switches on
With the upgrade installed, Hera can now operate the remaining instruments on its “asteroid deck” and the autonomous navigation functions it needs to safely approach and orbit a body as small and low-gravity as Dimorphos, where conventional Earth-taught piloting techniques do not apply. The same update activates the inter-satellite communication links Hera will use to coordinate with Juventas and Milani once all three spacecraft are operating in the vicinity of the asteroids.
Closing the loop on planetary defence’s first real-world test
Hera is the European follow-up to NASA’s Double Asteroid Redirection Test (DART), which deliberately collided with Dimorphos in September 2022 — the first time humanity measurably altered the orbit of a Solar System body. DART proved that a kinetic impactor could shift an asteroid’s trajectory, but it could not stay behind to examine the aftermath. Hera’s job, once it arrives at the binary system in autumn 2026, is to survey the impact site up close: measuring Dimorphos’s mass, internal structure, and the crater DART left behind, turning a single successful experiment into a repeatable, well-characterised planetary-defence technique that mission planners could use again if a real asteroid threat were ever identified.
Hera launched in October 2024 and used a Mars flyby in spring 2025 to help refine its trajectory en route to the Didymos system.
What comes next
With its full instrument suite and autonomous-navigation software now active, Hera moves into its asteroid-approach phase ahead of the planned rendezvous with Dimorphos. The coming months will involve further calibration of the navigation cameras, lidar and other sensors the spacecraft will use to close in on a target with barely any gravity of its own — a very different flying environment from the deep-space cruise Hera has been in since launch.
Source: European Space Agency, “Deep space software upgrade for Hera’s asteroid visit,” esa.int/Space_Safety/Hera.
