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A601 Monge bâtiment d'essais et de mesures (BEM)

The Le Monge is a French Navy laboratory, test, and instrumentation ship equipped with a meteorological and Laser Radar (LIDAR) station, a telemetrystation, an optical station, and five radar stations. The French tracking ship Monge with its Armor and Gascogne radars. The bâtiment d'essais et de mesures (BEM) Monge is a fundamental element of the test device sized to collect and use all the parameters of missile fire in flight. It is suitable for future ballistic programs that will implement more and more objects with increased stealth. It is a unique mobile test center in Europe.

Built by Chantiers de l'Atlantique in Saint-Nazaire, the ship measures 230 meters long, and is the second largest ship of the Navy. A few meters after the aircraft carrier Charles de Gaulle. Despite its size, the Monge is far from being the best-known ship. Discretion is not trivial. Some of its missions are marked with the seal of confidentiality. This concentration of floating technology, in service since 1992, remains one of the guarantors of the credibility of French nuclear deterrence. The stakes are high because the tests are the process of validating the missile systems, and also to show the world that the French deterrence is effective.

This ship had a standard displacement 17,760 tons, fully loaded displacement 21040 tons, length 225.30 meters, beam 24.84 meters, draft 7.76 meters. The action system is 2 SEMT- Pierre Stiker 8 PC 2.5L 400 diesel engines, the single Taiwan power 6615 kilowatts, the single axle advancement, uses an adjustable pitch propeller. Has shou the propulsion system, the power 1 megawatt, and is equipped with the stabilization ballast tank, causes it time the low speed navigation biggest roll angle to lower under 6 levels of sea conditions to 9°. Maximum speed 16, endurance 13031 nautical miles /15. Shipboard installs a generator in addition, provides the electric power for the ship-borne equipment, the power 7650 kilowatts, may satisfy one to have 20,000 population small cities to use electricity. The crew establishes 120 people (military officer 10 people), with 100 military and civilian technicians.

The Monge test and measurement ship was admitted to active service on November 5, 1992. Beaune, birthplace of Gaspard Monge, has been the sponsor city of Monge since 1993. The second largest military vessel in the French Navy, the Monge, a test and measurement vessel, has been carrying out the missions necessary for French nuclear deterrence since 1992, as well as observation missions. Equipped with the most powerful radars in Europe, "the Monge is capable of detecting a 2 euro coin at 800 kilometers", says the building commander.

Le Monge is a real city. A maze of corridors that houses a crew of 200 sailors. A vessel that must also be maintained and brought to life between missions. And like any self-respecting city, the ship has its streets: plaques indicate the names of the various corridors. A funny and strange detail for beginners. Each ship has a godmother city. For Monge it comes to Beaune, Gaspard Monge's birthplace, French mathematician who gave his name to the vessel. So street names that are affixed in the corridors are those of the streets of Beaune.

It is difficult not to see it. It attracts the gaze of any visitor at the Brest naval base with his imposing white silhouette and its series of radars and antennas. Nicknamed "The ears of France” alluding to its missions monitoring ballistic missile tests, the Monge is a BEM (test and measurement vessel) of the Navy National. Based in Brest, its main missions are the trajectography of ballistic missiles, satellite tracking and setting up or tracking aerial targets. Since 2007, Le Monge has also been responsible for collecting and using Ariane 5 flight parameters. With a length of 225.6 meters for a width of 24.8 meters and displaying a displacement of 21,040 tons, the Monge is propelled by two engines of 4,500 hp, which allow it to navigate at a speed of 16 knots. It is also equipped with 6 diesel alternators of 1,500 KW each [ie the equivalent of the consumption of a town of 15,000 inhabitants] in order to supply its numerous measuring and monitoring instruments. Indeed, this vessel is equipped with an aerial search radar, 2 navigation radars, 10 radar and tracking antennas as well as optronic and telemetry sensors. Operated by a crew of 126 sailors, it accommodates on board a hundred scientists and engineers from the General Directorate of Armaments [DGA].

Based in Brest, the Monge spends an average of four months a year at sea and has a range of 60 days and 15,000 nautical miles. One of the important missions is also the pursuit of space debris in order to determine exactly the trajectory of this debris in order, possibly, to deflect the satellite to avoid a collision. It monitors so-called risky returns such as that on land from the Mir station.

The ship's role role is to be at the arrival of the missile to analyze the final trajectory, several thousand kilometers from the launch pointr. The Monge thus did not collect data during the failed test of an M51 ballistic missile which exploded shortly after its launch, off Finistère. The ship is equipped with three of the four most powerful radars in Europe as well as an optronic turret. To make these ultra-precise measurements, the ship has three radars: the Armor 1, the Armor 2 and the Normandie. These radars are like laser pointers, they allow very precise views on given objects. On the other hand, they are not at all suitable for researching large-scale objects. To make these monsters of technology work, the Monge has six generators, namely the equivalent of the energy used by a city of 20,000 inhabitants. Eighty people, out of the 200 who make up the crew, are responsible for operating and using these state-of-the-art tools.

The extreme precision of the measurements required explains the impressive size of the boat, a guarantee of stability, and its color. "White helps limit the risk of heat expansion of the building, which could distort measurements," said the officer. Since strategic missile tests only take place every two years on average, the Monge, which has a crew of 200 people including 80 dedicated to measurements, has also diversified its missions.

At the end of 2018, the "Monge" test and measurement building came out of its 3rd major technical shutdown. After a year of maintenance work carried out in Brest, it is now again ready to carry out its missions. Meet the missions that await him, without delay and with all the performance required for the expected measures. It is with this objective in sight that the "Monge" test and measurement building entered a major technical shutdown in October 2017. A technical shutdown which lasted one year and which has just been completed. In 2019 this exceptional means of measurement is operational again.

The 2018 major technical shutdown of the "Monge" exclusively concerned maintenance work on the platform and the measurement system. The vessel is thus passed to the basin for a complete maintenance of its submerged parts, whether it is its hull, its propulsion system and the appendages which are used for its control such as the rudder or the hull valves. A large part of the superstructure has also been refurbished (front deck, chimney, helicopter platform, all the pediments and the aerial and telemetry deck).

Work on the measurement device focused on radars, aerology equipment including Lidar, and the neutralization remote control. The "Monge" has three radars with extraordinary trajectography and analysis capabilities. Unparalleled in the world, it can follow a coin that moves several hundred kilometers away! On this occasion, the Normandy radar antenna underwent its first major renovation (decennial refit) since it was put into service in 2009.

Information systems have also been overhauled. In particular, the upgrade of the radar information system as well as a new position and attitude management system. The other means of measurement have been the subject of smaller interventions, either by upgrading or by a minor change. Finally, this major technical shutdown also made it possible to carry out a good number of periodic maintenances essential to the proper functioning of the installations: optical turret, telemetry device and weather equipment.

Page last modified: 30-06-2021 12:05:30 ZULU