KM3NeT - ARCA sea campaigns

Liveblogs during sea campaigns for ARCA

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.

Welcome, ARCA62!

23 September 2026 – The KM3NeT Collaboration is happy to report about a very successful sea campaign conducted at the KM3NeT ARCA site in the past two weeks. The campaign led to a significant step forward in the construction of the apparatus, including an enlargement of the submarine infrastructure and the detector and an upgrade of its acoustic positioning system. Read more

Welcome ARCA33 and ORCA24!

28 October 2024 – The latest sea campaigns at both the KM3NeT’s ARCA and ORCA sites have led to major progress in expanding detector installations and improving calibration systems.

The number of detection units in operation in the deep sea has been increased to 57: 33 in ARCA and 24 in ORCA.

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KM3NeT/ARCA enlarged to 28 Detection Units

10 October 2023 – An important two-week marine operation has been successfully carried out at the KM3NeT ARCA site, offshore Capo Passero, Sicily in September.

The campaign was performed with the Optimus Prime, equipped with a FUGRO underwater vehicle (ROV). The ship set sail from Malta on Monday, 11 September and came back to the port at the end of the operation on Thursday, 23 September.

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Major upgrade of ARCA’s seafloor network

22 November 2022 – After 4 years of  activities carried out by the Italian funding agency INFN and Alcatel Submarine Networks, part of Nokia, the new subsea network for KM3NeT ARCA, funded under the Idmar regional project in Italy, is now complete.

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New sea campaigns at both KM3NeT sites

12 September 2022 – New sea campaigns were performed last week for both ARCA and ORCA. The purpose was to prepare the field for next installation phases of the detectors as well as to deploy new detection units and acoustic beacons – the latter are autonomous calibration devices which run on batteries and need to be replaced after some time.

The number of detection units in operation in the deep sea has been increased to 32 (comprising almost 18,000 photomultipliers): 21 in ARCA and 11 in ORCA.

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Sea campaign for ARCA concluded: welcome, KM3NeT/ARCA19!

14 June 2022 – The sea campaign for enlarging the KM3NeT/ARCA submarine telescope has been completed with full success!

During the last few days, all detection units loaded on Handin Tide for the second phase of the operation were carefully installed on the sea bottom. This was achieved at a record-breaking speed, with 7 detection units installed, connected and unfurled in less than 48 hours!

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Welcome KM3NeT/ARCA19

14 June 2022 – The sea campaign for enlarging the KM3NeT/ARCA submarine telescope which was started on June 2, has been completed today with a full success. As a result, data taking with ARCA has been resumed with 19 detection units in operation!

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