Two more successes in the construction of ARCA and ORCA

9 October 2026 – The KM3NeT Collaboration is celebrating a period of intense and highly successful marine operations, with two more significant steps performed last week for ARCA and ORCA.

ARCA: CTF3 installed

During a marine campaign conducted by Alcatel Submarine networks, the Cable Termination Frame 3 (CTF3) was installed at the ARCA deep-sea site. This high-tech node serves as a vital junction connected to the end of the second branch of ARCA’s second main electro-optical cable to serve the second building block of the apparatus. CTF3 is equipped with 4 Medium Voltage Converters to regulate the high-voltage power delivered from shore to the level required by the offshore network, and is designed to distribute power and data through 16 electrical and 16 optical wet-mateable connectors.
Welcome, ARCA CTF3!

ORCA: A fight against environmental conditions to reach ORCA44
Meanwhile, at the ORCA deep-sea site, in spite of unstable weather conditions, a sea campaign was conducted to deploy new detection units and perform maintenance operations on the submarine node and some acoustic devices.
At the end of the operation, ORCA reached a configuration with 44 detection units installed.
Welcome, ORCA44!

Sonar map of the deep-sea installations at ORCA at the end of the operation, comprising two nodes for submarine connections (marked N1 and N2), the Module Instrumented Interface (marked MII), which is a hub for connecting deep-sea instrumentation, and a total of 44 detection units (DUs) – those installed during the latest campaign are highlighted. Out of the field of view are the calibration base and the instrumentation unit connected to it.

The Collaboration wants to convey its deepest gratitude to everyone involved in these important steps, in particular to the offshore and onshore crews during the operations. The ARCA team tackled this deployment immediately after an exhausting 17-day marine campaign, while the ORCA team maintained absolute focus through a tense, weather-delayed week.