One project completed as part of our ongoing cooperation with IMS Ingenieurgesellschaft mbH Hamburg, the general contractor, and the Centre National d‘Etudes Spatiales (CNES) Toulouse, was the recovery of the Ariane V Mission 517 booster rockets from the sea off the coast of French Guiana in Central America. Ariane 5 Mission 517 was launched on 11 December 2002.

Approximately 90 seconds after the Ariane 5 Mission 517 took off and at a height of around 60 km, it became evident that the launcher was experiencing problems with the cooling circuit for the main stage; a few seconds later it became necessary to detonate the launcher.

Before this happened, however, the booster rockets detached from the main stage according to plan. After the ballistic phase, with a zenith at a height of approx. 110 km, the boosters re-entered the earth’s atmosphere on parachutes and landed as planned approx. 280 nautical miles to the east of the Space Station, which is located on the coast by Kourou.

Despite the incessantly bad weather, with wind speeds of more than 15m/sec and waves between 4 and 6 metres high, the sea recovery operation was successfully completed. During this mission, which involved dives with light umbilicals and radio contact from large offshore vessels, we managed to set new fulfilment standards while maintaining the highest possible levels of safety

Our recovery plan was a great success and more than met the demands posed by the exceptionally tough conditions.

When the Ariane 5 was launched the recovery vessel used by IMS, which was fitted with specialized equipment and had on board Nordseetaucher’s recovery and diving team, was located in a stand-by position approx. 6 and 14 nautical miles from the target area in the Atlantic where the boosters were expected to land. The equipment comprised dive containers, water jet-propelled offshore rescue boats, decompression chambers and ROVs (remote-controlled vehicles fitted with underwater cameras).

The two boosters were safely landed on 6 and 8 January 2003 in Pariacabo, the port of the European Space Centre in Kourou, French Guiana. It was the successful conclusion of a unique mission to retrieve the booster rockets after deployment and bring them back for indepth examination to establish which technical modifications were required.