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Envisat's night eye supports icebound ship rescue in Antarctica

Press Release From: European Space Agency
Posted: Friday, August 2, 2002

A German supply vessel and its crew are stuck in Antarctica until October after severe winds and ice fields 7 metres high forced an Argentinian rescue ship to retreat. A radar image from ESA's Envisat is helping the icebreaker plot its route to safety.

The German vessel 'Magdalena Oldendorff', with a skeleton crew of 17, has been trapped in ice since 11 June. The Argentine icebreaker, 'Almirante Irizar' was dispatched from Buenos Aires last month and has been trying to lead them to safety since 19 July. Finally on Tuesday 30áJuly, in temperatures of -32ádegrees C and rapidly closing ice, they had to abandon the attempt. Before leaving, the icebreaker helped the Magdelena Oldendorff to a safe position in the Bay of Muskegbukta and transferred enough supplies for the crew to survive the winter.

The German Federal Maritime and Hydrographic Agency asked ESA to provide Envisat radar images to support the rescue efforts. During the winter months the hours of daylight are very limited. There are only two hours when visibility is sufficient for helicopter reconnaissance missions. But Envisat's Advanced Synthetic Aperture Radar (ASAR) can view an area 400 km wide with unprecedented accuracy during the polar night.

The German agency passed the Envisat data on to the US National Ice Center, Washington, DC, and to the Argentine Navy, which sent it on directly to the Argentine icebreaker to assist in plotting the best possible route through the weakest points in the ice.

Captain Manuel Picasso of Argentina's Naval Glaciological Center, Hydrographic Service sent his personal thanks for the ASAR data to the ESA team.

Klaus Struebing of the German maritime agency explained the relevance of the data. "Satellite images are a most useful tool for ice services to provide ice information to their users. The data are mostly used by trained interpreters and the extracted info transferred to ice charts. For trained captains and ice pilots the image itself is the best information -- if it can be read properly. The modern radar tools such as RadarSat, SAR on ERS and now ASAR on Envisat are extremely useful because the can provide data undependently from day-time and cloud cover."

Obtaining this image proved quite a challenge, as Envisat Mission Manager Henri Laur explains. "There are two small areas in the world where we cannot recover ASAR data with the onboard recorders, and the ship was precisely within one of those areas", said Laur. "This required manual intervention by the ESA team, briefly interrupting acquisition of data from other Envisat instruments."

Most of the 79 Russian scientists and 28 crew aboard the Magdalena Oldendorff were rescued in late June by helicopters from a South African research vessel, but the 17-man skeleton crew remained so as not to abandon the Magdalena. The Magdalena's Master Ivan Dikiy says: "Regardless of our waiting position the mood is good onboard. To support this sweets, cigarettes and sometimes a beer will be provided to the crew."

In October, when the Magdalena Oldendorf is ready to make its escape, ESA will acquire another Envisat image of the area and provide it to the German Maritime Agency. The data will be used to analyse ice melt and the location of larger bergs in the area to assist in the departure of the ship.

Related articles

* Why is ASAR useful for assisting polar operations?
http://www.esa.int/export/esaCP/ESATE976K3D_index_0.html

* ESA keeps vigil on the Antarctic ice pack
http://www.esa.int/export/esaCP/ESA6CV66K3D_index_0.html

* Envisat's MERIS captures image of Hurricane Elida
http://www.esa.int/export/esaCP/ESATF676K3D_index_0.html

* What puts the "Advanced" in Envisat's Advanced Synthetic Aperture Radar?
http://www.esa.int/export/esaCP/ESAZGOG18ZC_FeatureWeek_0.html

* The first Envisat check-up on the Earth
http://www.esa.int/export/esaCP/ESAQNGF18ZC_index_0.html

Related Links

* Envisat Results
http://www.esa.int/envisat

* Earth Observation Programme
http://www.esa.int/export/esaSA/earth.html

* Federal Maritime and Hydrographic Agency of Germany
http://www.bsh.de/3172.htm

IMAGE CAPTIONS:

[Image 1: http://www.esa.int/export/esaCP/ESAOC976K3D_index_1.html] Icebreaker Almirante IrÝzar moving northwards northwards with German vessel Magdalena Oldendorff close behind (28 July). Worsening conditions forced the rescue attempt to be called off. Having left the Magdalena Oldendorff in a safe location in the Bay of Muskegbuta the icebreaker is trying to break through the Antarctic ice-belt headed for Buenos Aires. Envisat ASAR data has been supplied to the icebreaker to assist in plotting the safest course though weaker points in the ice. Credits: Argentine Navy

[Image 2: http://www.esa.int/export/esaCP/ESAOC976K3D_index_1.html#subhead1] This image was acquired by Envisat's Advanced Aperture Radar (ASAR) on 31 July 2002, in support of rescue efforts in Antarctica. The ASAR wide swath image shows a 400 km stretch of the Antarctic Coast in Queen Maud Land. At this time of year, a belt of sea ice up to 1100 km wide surrounds the Antarctic Continent and its ice shelves and gives the sea in this image a textured grey appearance.

At the time of this acquisition, the supply ship Magdalena Oldendorff was sheltering in a bay known as Muskegbukta on the Eastern side of the Jutulstraumen Ice Tongue. Her location is visible on the very edge of this scene (marked in blue). The icebreaker Almirante Irizar's course through the ice-infested waters is shown as a series of GPS location measurements, one of which was made within minutes of the acquisition (shown in yellow). She will continue to skirt the ice shelf until reaching safer waters in the vicinity of the Astrid Rise (longitude 12E, off the image) in order to make her return to Buenos Aires. The MŘhlig-Hofmann Mountains are visible in the bottom left corner. Glaciers flowing from the mountains feed the Fimbul Ice Shelf, visible as a bright white swath bordering the South Atlantic Ocean.

Technical Information:

Instrument: Advanced Syntetic Aperture Radar (ASAR)
Mode: Wide Swath
Date of Acquisition: 31 July 2002
Orbit number: 2177
Orbit direction: Ascending
Polarisation: H-H Resolution: 150 metres

Credits: ESA 2002

[Image 3: http://www.esa.int/export/esaCP/ESAOC976K3D_index_1.html#subhead2] Close-up of Envisat ASAR image acquired on 31 July 2002, in support of a rescue mission in Antarctica. The area of the Jutulstraumen Ice Tongue is shown in this close-up image (100 km wide) focusing on the positions of the ships at the time of acquisition. The Magdalena Oldendorff is at anchor in a bay called Muskegbukta, and the icebreaker Almirante Irizar is making her way back to Argentina.

In this ASAR image, thick sea ice appears with a textured grey signature in contrast to the bright ice shelf. It is evident that the two neSons are separated by a narrow belt of clearer water, which is facilitating the icebreaker's eastward passage. The whole area is littered with hazardous icebergs, visible as bright specks against the darker background.

Technical Information:

Instrument: Advanced Synthetic Aperture Radar (ASAR)
Mode: Wide Swath
Acquisition date: 31 July 2002
Orbit number: 2177
Orbit direction: Ascending
Polarisation: H-H
Resolution: 150 metres

Credits: ESA 2002

[Image 4: http://www.esa.int/export/esaCP/ESAOC976K3D_index_1.html#subhead3] The ice-bound German-owned Magdalena Oldendorff is seen from a South African Air Force Oryx helicopter Thursday June 27, 2002 near the Novolazarevskaya station in the northeast Antarctica. Scientists and crew members were rescued off the vessel by the SA Agulhas which arrived back in Cape Town Wednesday July 10, 2002. Credits: AP Photo-Edwuan Teich

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