November 2026 Mission Telemetry Review: NKUA/ESA’s 8U ERMIS-3 Closes a 100 Mbps LEO-to-Ground Laser Link as ESA’s Hera Arrives at Didymos with 6U CubeSats Milani & Juventas
November 2026 nadir lab. engineering analysis examining two European nanosatellite milestones reported by ESA in early November 2026: closed-loop 100 Mbps optical LEO-to-ground laser communications on Greece’s 8U ERMIS-3 CubeSat and Hera’s rendezvous with binary asteroid Didymos–Dimorphos carrying the 6U XL CubeSats Milani and Juventas.
Two ESA mission bulletins published in the first week of November 2026 highlight how multi-unit CubeSats now operate across regimes once reserved for 200+ kg spacecraft: sub-milliradian free-space optical (FSO) downlinks from Low Earth Orbit and multi-payload geophysical characterization at near-Earth asteroids.
On 3 November 2026, ESA Connectivity and Secure Communications reported that ERMIS-3—an 8U CubeSat developed under the National and Kapodistrian University of Athens (NKUA) within the ESA Greek CubeSat In-Orbit Validation programme and launched on SpaceX Transporter-16 (30 March 2026)—established a bidirectional acquisition and 100 Mbps optical downlink between its onboard Astrolight ATLAS-1 laser terminal and Aristotle University of Thessaloniki’s HolOGS-1 optical ground station in northern Greece. Unlike UHF or S-band links whose 10°–60° beamwidths forgive degree-level ADCS pointing errors, near-infrared 1550 nm optical downlinks require arcminute-class body pointing supplemented by fine-steering mirrors and closed-loop upward beacon tracking through atmospheric scintillation.
Two days later, on 5 November 2026, ESA Space Safety published Hera’s first close-up Asteroid Framing Camera imagery of (65803) Didymos and its moonlet Dimorphos from approximately 60 km range, marking arrival at the DART kinetic-impact target following launch on 7 October 2024. Stowed inside Hera’s Asteroid Deck Deep Space Deployers are two ~12 kg 6U XL CubeSats added to the nadir lab. mission database in this release: Milani (Tyvak International, carrying the ASPECT visible/near-IR hyperspectral imager and VISTA dust detector) and Juventas (GomSpace, carrying the JuRa 60 MHz monostatic radar and GRASS gravimeter).
Published Proceedings, Open-Access Papers & Primary Dossiers
CELESTRAK SATCAT & TELEMETRY RECORD
Verified Spacecraft Key Facts & Orbital Dossier
| Spacecraft | Class | Operator / Country | Launch & Vehicle | NORAD / COSPAR | Orbit & RF Downlink | Catalog Status |
|---|---|---|---|---|---|---|
ERMIS-3 | 8U | National and Kapodistrian Univ. of Athens (NKUA) / ESA GR | Falcon 9 (Transporter-16) · Exolaunch EXOpod Nova | Unassigned | 401.3125 MHz, 2218 MHz, 8366.65 MHz (UHF/S/X) | Active |
Milani | 6U | European Space Agency (ESA) & Tyvak International EU | Falcon 9 (Hera) · Hera Deep Space Deployer | Unassigned | Heliocentric rendezvous with binary asteroid (65803) Didymos–Dimorphos S | Active |
Juventas | 6U | European Space Agency (ESA) & GomSpace EU | Falcon 9 (Hera) · Hera Deep Space Deployer | Unassigned | Heliocentric rendezvous with binary asteroid (65803) Didymos–Dimorphos S | Active |
LICIACube | 6U | ASI (Italian Space Agency) & Argotec IT | Falcon 9 (DART) · Spring Dispenser on DART | Unassigned | X | Completed |
MarCO-A / MarCO-B | 6U | NASA JPL US | Atlas V 401 (InSight) | Unassigned | Heliocentric (Mars flyby) X | Completed |
Catalogued Mission Summaries & Flight Notes
- ERMIS-3 (8U, 2026):
- Greek 8U CubeSat developed by NKUA under the ESA Greek CubeSat In-Orbit Validation project; demonstrated a 100 Mbps LEO-to-ground optical laser communication link between its Astrolight ATLAS-1 terminal and AUTh’s HolOGS-1 optical station in autumn 2026.
- Milani (6U, 2024):
- ESA 6U XL deep-space CubeSat (~12 kg) carried aboard the Hera planetary-defense mothership, arriving at the Didymos–Dimorphos binary system in November 2026 with the ASPECT visible/near-IR hyperspectral imager and VISTA thermogravimetric dust detector.
- Juventas (6U, 2024):
- ESA 6U XL deep-space CubeSat (~12 kg) delivered to Didymos–Dimorphos aboard Hera in November 2026 to perform the first low-frequency radar tomography of an asteroid interior (JuRa 60 MHz radar) alongside the GRASS surface gravimeter.
- LICIACube (6U, 2021):
- Italian 6U deep-space CubeSat (14 kg) deployed from NASA’s DART spacecraft 15 days before impact; autonomously tracked and imaged the kinetic impact plume on asteroid Dimorphos from 55 km distance.
- MarCO-A / MarCO-B (6U, 2018):
- The first interplanetary CubeSats. They relayed InSight’s landing data of 26 November 2018 in near real time. Last contact: WALL-E on 29 Dec 2018, EVE on 4 Jan 2019. The mission was ended in February 2019.