The European Space Agency’s (ESA) Hera mission, part of an ambitious planetary defense initiative, has successfully received initial signals from its two CubeSat passengers, Milani and Juventas.
Launched on October 7, the CubeSats are now en route to the asteroid Dimorphos to conduct a follow-up investigation of the DART (Double Asteroid Redirection Test) impact from 2022. This mission milestone marks ESA’s first use of CubeSats beyond Earth’s orbit, setting a precedent for future planetary defense technology.
Testing and Verifying CubeSat Systems
Following their launch, each CubeSat completed a series of essential system verifications. The CubeSats, both approximately the size of a shoebox, underwent a “stowed checkout” test, where mission controllers verified basic power, stability, and communication systems. Over an hour, engineers confirmed that the avionics, payloads, and inter-satellite links were functioning as expected, ensuring that the CubeSats are equipped to operate in the deep-space environment on their way to Dimorphos. Franco Perez Lissi, Hera’s CubeSat Engineer, highlighted the significance of this achievement, stating, “This commissioning is a significant achievement for ESA and our industrial partners,” underscoring the importance of successful CubeSat integration for future missions.
The two CubeSats have specific scientific roles on their mission to Dimorphos. Juventas, built by GOMspace, is equipped with a radar designed to probe the internal structure of Dimorphos, marking the first time radar technology will be used to study the interior of an asteroid. Meanwhile, Milani, developed by Tyvak International, will conduct a multispectral analysis of Dimorphos’s mineral composition, helping scientists better understand the asteroid’s structure and the physical properties of its surface. Both CubeSats will remain in stowed positions aboard Hera until the spacecraft arrives at Dimorphos in 2026, at which point they will deploy for close-proximity data collection in the asteroid’s low-gravity environment.
Ground Control and Future Activations
Throughout the journey to Dimorphos, ESA will periodically reactivate both CubeSats to perform system health checks, battery recharges, and software updates. This routine testing is essential for ensuring the longevity and operational readiness of the CubeSats once they reach their destination. Sylvain Lodiot, Hera’s Operations Manager, shared insights into this rigorous process, explaining, “We validated the entire ground command infrastructure, from data transfer to monitoring,” which was overseen by ESA’s European Space Security and Education Centre (ESEC). This detailed monitoring system enables ESA to maintain reliable communication with the CubeSats despite the challenges posed by the vast distance between Earth and the spacecraft.
To support these deep-space communications, ESA has established a dedicated control protocol for the CubeSats, ensuring that ground teams can continually monitor the CubeSats’ status and execute critical software and hardware adjustments as needed. These periodic reactivations are scheduled every two months and are a key component of the mission’s strategy to keep the CubeSats fully operational by the time they reach Dimorphos, which is roughly 11 million kilometers from Earth.
A Milestone in Planetary Defense and Deep-space Exploration
The Hera mission’s use of CubeSats in deep space represents a significant advance in planetary defense capabilities, building on the success of NASA’s DART mission. By deploying Milani and Juventas, ESA aims to gather valuable follow-up data on the structural and mineral makeup of Dimorphos, allowing scientists to assess how the DART impact may have altered the asteroid. This is particularly relevant for future planetary defense strategies, as such data can refine models on how asteroids respond to kinetic impacts, a critical insight if Earth ever faces a real asteroid threat.
ESA’s successful integration of CubeSats into deep-space operations not only enhances Hera’s mission objectives but also demonstrates how small satellites can contribute to large-scale space missions. By enabling advanced science in a compact form, CubeSats like Milani and Juventas highlight ESA’s commitment to innovative solutions in planetary defense and exploration.
