KM3NeT - ORCA sea campaigns

Liveblogs during sea campaigns for ORCA.

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.

The field is getting crowded!
This is a sonar map of the ORCA site after the installation of the new detection units. Also marked in the image are the various components of the submarine infrastructure, comprising a junction box (“JB1”), a module for interface with oceanographic instrumentation (Module Interface Instrumented – MII) and a calibration structure (Calibration Base – CB).

As usual, the operation was performed with two ships: the Castor 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, for submarine operations.

Everything worked very smoothly – 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!

 

The Castor at the end of the sea campaign.

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.

Despite bad weather at the ARCA site, the so-called Phase-1 part of the apparatus was completed, while construction of Phase-2 was started with the installation of two new junction boxes, three detection units (exploiting a new data acquisition architecture), and calibration components. The operations also included important maintenance tasks, such as recovering and replacing acoustic beacons. All optical modules of the deployed strings are fully operational. KM3NeT/ARCA now comprises 33 detection units.

At the ORCA site, a 60-hour calm weather window allowed the team to deploy the Calibration Unit (Calibration Base+Instrumentation Unit) and to install an additional detection unit. After these successful installations, node 1 of ORCA is complete and fully functional, an important milestone in the construction of ORCA. The total number of functional detection units at ORCA has now reached 24.

These recent efforts at both sites underscore KM3NeT’s expanding capability in detecting and studying neutrinos from the sea’s depths. The whole Collaboration extends its gratitude to the offshore and onshore teams whose hard work made these successful operations possible.
A furled detection unit ready for the deployment at the ORCA site
ORCA offshore team on the Castor 02 ship
Components for ARCA on the deck of the Optimus Prime ship: in the foreground is one junction box, behind it there are a couple of spools with the submarine interlink cables and then some detection units
ARCA onshore shift crew at the site of Portopalo

 

 

 

 

 

 

 

 

 

 

 

ATLAS comet visible from the harbour of Portopalo di Capo Passero

 

Sonar scan of the ORCA site taken by the ROV at the end of the operation. The anchors of the detections Units (DUs), the junction box (JB1), the Calibration Base (CB), the Instrumentation Unit (IU) and the Module Instrumentation Interface (MII) are all visible.

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.

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

New marine science sensors coming online

24 April 2023 – Following a successful sea operation, the 16-19 April 2023, a collection of new marine science instrumentation is now connected to the Laboratoire Sous-marin Provence Mediterranee (LSPM)) sea floor infrastructure at the KM3NeT/ORCA site, near Toulon, France.

During the three day sea operation the so-called ‘pre-SJB’, developed by CPPM Marseille, was connected into the seafloor network. The pre-SJB is a passive junction box housing an AC power transformer and a sea return electrode. During the same operation a remotely operated vehicle (ROV) connected an interlink cable between the pre-SJB and the previously deployed SJB.

The SJB (Scientific Junction Box), developed by Ifremer, is a junction box with six output dedicated to marine science instrumentation. The Pre-SJB/SJB are located about 3.7 km west of the main KM3NeT/ORCA detector. The SJB with its associated instrumentation had already been deployed about a year ago and was waiting for the pre-SJB installation to come online. An earlier incarnation of the SJB was previously installed on the ANTARES junction box.

The instrumentation currently connected to the SJB includes the BathyBot seafloor crawler, its docking station BathyDock (MIO/DT-INSU-Marseille) and BathyReef (an artificial reef), a broad-band seismograph (GeoAzur-Nice), a germanium gamma spectrometer (CPPM-Marseille,) and a stereo biocamera (IP2I-Lyon).

Two ships were involved in the sea operation: the Raymond Croze of Orange Marine and the Janus II of SAAS.

The ROV being deployed from Janus II.
The ROV being deployed from Janus II.
The Raymond Croze.
The Raymond Croze of Orange Marine.
Deployment of the Pre-SJB.
Deployment of the Pre-SJB from the Raymond Croze.
Layout of the LSPM instrumentation connected to the SJB.
Layout of the LSPM instrumentation connected to the SJB.

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.

The operation was performed with the Castor ship of Foselev, for deployment of the detection units, and with the Janus II of SAAS (formerly Comex), equipped with a deep-sea remotely operated vehicle, for submarine operations.

The KM3NeT Collaboration congratulates the crews on the two ships, the team who performed careful checks from the shore station during the campaign, and all the teams who contributed to the construction of the detection units, for the success of the operation.

One of the ORCA detection units starting its journey from the Castor to the sea floor, 2500 m below. In the background is the Janus II.

 

Sonar map of ORCA, showing 14 detection units (the 15th one is beyond the boundary of the map). The 4 in the bottom part of the picture are the new ones installed.

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.

After installation of a third junction box at the ARCA site, this site is now fully equipped for hosting the so-called Phase-1 of the project, comprising the first 31 detection units and the calibration unit of the apparatus.

The ARCA sea campaign represented the final action of the IDMAR project in Italy, supported by Regione Sicilia.

These operations were made possible by the dedication of hardware teams and the onshore and offshore teams at the two sites – the Collaboration is very grateful to them.

The newly added junction box of ARCA on the sea bottom.
Detection unit deployment at the ORCA site.

Welcome, ORCA-10!

22 November 2021 – Four new detection units have been added to ORCA with a 5-day intense and successful sea operation.

The operation has been performed with two ships: the Castor, equipped for deployment and precise installation of the detection units on the sea floor, and Janus, equipped with a remotely operated vehicle used for inspecting and for connecting the new units to the submarine infrastructure.

You can read all details of the operation in the daily reports published in our ORCA-blog.

Data taking with 10 detection units has been started!

One of the new detection units of ORCA outboard of Castor, preparing to its journey to the seafloor, 2,500 m below.

Sea campaign completed: 10 detection units in operation at ORCA

22 November 2021 – Excellent progress today, with the work finalized on the two detection units lately deployed: after a confirmation from the tests that both were ok, the unfurling was started of the two units. The launcher vehicles were safely recovered from the Castor; the ROV inspected both units after unfurling, confirming that both are in nominal configuration. A new functionality test was then performed from the shore station to ensure that both detection units work nominally.

As the sea condition rapidly degraded during the day, it was decided to quit the campaign. The remaining detection units on deck will be saved for next time.

The final outcome of the campaign is: ORCA enlarged from 6 to 10 detection units!

The KM3NeT Collaboration is grateful to the heroic teams who have made such great effort onboard the two ships and in the shore station, as well as to all institutes which contributed to the construction of the detection units. We look forward to the next deployment campaign. Having said that: it’s time to resume data taking with an enlarged ORCA-10 now!

Approaching the ORCA submarine junction box at 2,500 m depth – in the foreground is the connector that the ROV is preparing to plug on it.
The team onboard the Janus – on one of the screens is the sonar image of the ORCA telescope, showing the nodes and the detection units on the sea floor. Note that the operation was performed respecting all applicable rules for protection against COVID-19 – the team got so close together only for the purpose of the picture.
The team onboard the Castor showing the ’10’ sign in front of a recovered launcher vehicle.
The onshore team. The featured instrument is an Optical Spectrum Analyser, showing the signals of the 10 detection units of ORCA. Note that the operation was performed respecting all applicable rules for protection against COVID-19 – the team got so close together only for the purpose of the picture.

News from the ORCA campaign – hard work ongoing, bad weather approaching

21 November 2021 – The weather forecast does not look promising for next days. The main effort today was spent on some tuning of the equipment and preparation to next steps.

The situation at the sea bottom is: two new detection units have been already added to the ORCA detector; a third one, after installation, connection and test, is awaiting unfurling, and a fourth one is also on the sea floor awaiting to be connected – next step will be to connnect this one.

The video shows the overboarding of the ROV from the Janus – this takes place by means of a so-called A-frame (the structure at the stern of the ship which, rotating, reaches outboard).

Two new detection units added to ORCA… and counting

20 November 2021 – It was night and day again. The work continues around the clock when you are at sea. The second detection unit was also deployed, connected and tested last night. After that, unfurling was performed for the two detection units. A final test was then made from the shore to check that the two units are ok even after unfurling, et… voilà:  ORCA is enlarged to 8 detection units.

The campaign is now continuing with deployment of the next detection units; a third one is already on the sea bottom, connected and tested. A fourth one has been deployed in the evening: we will keep going until the deck is empty or the weather changes (the forecast is not ideal for next week): which of the two will happen first?

After unfurling of a detection unit, the launcher vehicle on which the unit is installed for deployment reaches the surface and is recovered for next campaigns.
Inspection of a detection unit, after touchdown on the sea floor (~2,500 m depth). The unit featured here is the fourth one which has been deployed in this campaign.