KM3NeT - ORCA sea campaigns

Liveblogs during sea campaigns for ORCA.

Welcome, ORCA-42!

8 July 2026 – A very successful sea operation took place during last week-end, leading to a new extension of the ORCA submarine telescope off the coast of Toulon, France.

During the operation, four new detection units were installed in the deep sea and connected to the detector in a record time of an average 8.5 hours of operation per unit.

Ancillary actions were also performed, including a deep-sea inspection of some detection units, recovery of one acoustic emitter of the positioning system which requires some maintenance and recovery of biofouling traps installed years ago which will provide new insights on how to preserve the transparency of the glass of the optical modules in the deep sea over very extended periods.

At the end of the operation, the apparatus comprises 42 detection units.

As usual, the operation was performed with two ships: the Castor 02 of Foselev, for deployment of the detection units, and the Janus II of SAAS (formerly Comex), equipped with the Apache deep-sea remotely operated vehicle (ROV), for submarine operations.

Many thanks to the crews offshore as well as to the team who performed the functional tests of the new detection units from the shore station and anyone else involved in making this great step forward possible!

Welcome, ORCA42!

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), a calibration base (CB) connected to an instrumentation unit (IU), and a total of 42 detection units (DUs) – those installed during the latest campaign are marked.


Welcome, ORCA-38!

20 April 2026 – A very successful sea operation took place last week, leading to a new extension of the ORCA submarine telescope off the coast of Toulon, France. Read more


Welcome, ORCA33!

15 October 2025 – A very successful sea operation took place last week, leading to a significant extension of the ORCA submarine telescope. Read more


Second node of ORCA installed

13 August 2025 – Last week we installed a second submarine node for the ORCA neutrino telescope. It is an important step in preparation of the next deployments of detection units for ORCA.

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4 new detection units installed in ORCA

16 May 2025 – This week at the ORCA site, a sea operation was performed with a twofold purpose: the recovery from the sea bottom of some oceanographic instruments which required some maintenance and the installation of a set of 4 new detection units. The number of detection units in ORCA has thus been increased to 28. 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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ORCA enlarged with four new detection units

15 June 2024 – A new marine operation took place in the last week for enlarging the ORCA deep-sea neutrino telescope.

Taking advantage of a spot of good weather of 48 hours, four new detection units were added to the apparatus.

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Three more detection units for KM3NeT/ORCA

1 May 2023 – During a two days sea operation, 27-28 April 2023, three detection units were successfully connected to the ORCA detector of KM3NeT in a record time of just over 24 hours. In addition, an acoustic beacon was recovered for battery replacement. The total number of deployed ORCA units is now 18, as visible in the sonar scan above.

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ORCA enlarged with 4 new detection units

12 December 2022 – During a sea campaign performed last week, ORCA has been enlarged by means of 4 new detection units. This brings the total of detection units deployed in ORCA to 15, comprising more than 7,500 photomultipliers.

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