Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Alkor	AL552a	30.03.2021 - 01.04.2021		Baltic Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Flogel Sascha	Helmholtz Centre for Ocean Research Kiel (GEOMAR)	Kiel	Kiel

Ziel der Reise / Objectives of Cruise:

AL552a: The expanding need for tools to investigate various parts of the world oceans such as the shelf seas and continental margins for scientific reasons is continually increasing while our ability to address questions concerning ocean change is fundamentally limited by the lack of key technologies for enabling in-situ experimentation and observation performing persistent sensor measurements in the ocean. The work carried out during this short ROBEX expedition will test the capability of the new GEOMAR MANSIO-VIATOR system. At the GEOMAR Helmholtz Centre for Ocean Research Kiel, the MANSIO-VIATOR (latin: harborage-traveller, Fig.1) system was designed. It comprises a stationary lander system and a mobile deep-sea crawler. The hangar is used for transport to the site of investigation and for recovery at the ocean surface as well as to recharge the lithium polymer accumulators on the crawler. The hangar facilitates data transfer from the lander system to the crawler and ultimately to the sea surface by acoustic modem. Within ROBEX, this approach is closest to the lander-rover systems used in space research and thus a true space analogue. During cruise 552a we will test new communication and homing functions that will enable VIATOR to locate the hangar MANSIO autonomously up to distances of km's. The communication is based on underwater acoustics with USBL modems from Evologics. Tuesday, 30-03-2021: We embarked at 7:00 and started the setup of all the hardware incl. WLAN antennas and communication devices such as USBL (moonpool). R/V ALKOR left the GEOMAR easthshore pier in Kiel harbor at 10:00 and headed north towards the Eckernforder Bucht where we arrived in our working area at 54?31.392' N and 010?05.126' E in the German EEZ at 11:30. Weather conditions were extremely fair with weak winds and clear skies. At 12:00 the MANSIO system was successfully deployed at 18 m water depth (54?31,388'N and 010?05,135'E). Next, we lowered the ships USBL to establish a connection with the lander. Various tests of the new SINAPS software package. Finally, we deployed the crawler VIATOR and the WLAN rig at 54?31,400'N and 010?05,201'E (18 m). All systems do work properly. The afternoon is filled with various test scenarios and setup of the new navigation frontend. We successfully performed multiple trajectory tests until midnight. End of station work at 24:00. Wednesday, 31-03-2021: At 08:00 we picked up the station work by performing multiple odometry runs. Resuming power on VIATOR is 3.7 V. At 10:00 the Zodiac was deployed to pick up the buoy of MANSIO to fix issues with the flash for the coming night. Station work continued with tests of various new ROS packages. Weather is exceptionally good. Clear skies at 12?C, southwesterly winds 1 Bft. In the afternoon we tested the new 'homing' function – an acoustically controlled algorithm to guide VIATOR to MANSIO from whatever position. End of station work at 02:30. Thursday, 01-04-2021: At 08:00 we picked up the station work by performing additional odometry/homing runs. Weather is fair. Clear skies at 8?C, with some shattered clouds. Later overcast, foggy. NW winds with 3.5 m/s. Resuming power on VIATOR is 3.56 V. At 10:00, we started to recover all the. We left the working area at 10:30 and headed back to Kiel – westshore pier where we arrived at 12:00. We continued with maintenance work on the crawler and started the charging process for the upcoming deployments. We disembarked at 14:00.

Messungen / Measurements