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Envisat concludes a busy second year in orbit   Images generated during the last year by Envisat instruments:
Seeing more of the world  One of Artemis’ payloads for communication directly between satellites is a laser-optical relay terminal called SILEX. It already achieved a world premiere in November 2001 transmitting a picture taken by SPOT4. Carrying three payloads plus a number of experiments, Artemis (Advanced Relay and Technology Mission Satellite) is being developed for testing and operating new telecommunications techniques. The L-band mobile payload allows two-way voice and data communications, via satellite, between fixed Earth stations and land mobiles - trucks, trains or cars - anywhere in Europe and North Africa. Artemis carries two payloads for communications directly between satellites, which received data from low-Earth-orbiting satellites and transmit them directly to Europe: -a laser-optical relay terminal called SILEX, -a double S/Ka-band terminal called SKDR. Artemis was launched in July 2001 on an Ariane 5 launcher.  Envisat communicates Artemis and the ESRIN data-procesing centre via Ka-band Data use doubled  ESRIN is a European Space Agency establishment located in Frascati, near Rome. This centre was created in 1966. One of its chief tasks consists of the utilisation of the telesurveying data obtained through the earth observation mission performed by ESA’s own satellites and those of other countries through the Earthnet programme. To carry out this task, ESRIN operates ground infrastructures consisting of some 30 data reception stations scattered all over the world. Once the data have been obtained, they are processed and filed before distribution to the final users, which is effected partly on a commercial basis, thus also generating economic returns. In the framework of the European earth observation programme, ESRIN is also responsible for the development operations regarding the Envisat satellite’s Payload Data System (PDS). This mission, with is load of complex, advanced instruments on board, will transmit earthwards an enormous quantity of data that must be processed for their various fields of application. A special building has been dedicated to housing the infrastructure control and management equipment for the ground segment of Envisat. Another fundamental task carried out by ESRIN is the management of the Agency’s entire informatics system. Frascati also hosts the team responsible for the programme for the development of a small three stage satellite launcher named VEGA, which is to weigh less than 1.000 kg. Mapping the atmosphere in near-real time  An image from the IFAC near-real time service showing distribution of water vapour across the northern hemisphere at a height of 21 km, based on data from Envisat's MIPAS instrument. Watching ocean waters  Mercator Ocean's System Prototype 2 ocean circulation forecasting model covers the Northern Atlantic plus Mediterranean Oceans with a resolution of 1 and 1/15 degrees, assimilating altimetry data from satellites including ESA's Envisat. ASAR homes in on earthquake zones  This interferogram is produced by combining two separate radar images of the same scene - in this case the area struck by the Bam earthquake in Iran, acquired December 2003 and February 2004. Combining the images in this way highlights alterations in the scene, with radar backscattered from these features having a different signal phase, manifesting in colourful interference patterns on the combined image known as fringes. These fringes can be used to measure tiny changes in the landscape occurring between images down to a maximum accuracy of a few millimetres, allowing geologists to see where faulting has occurred. For increased accuracy the spacecraft should return to as close as possible to the same point where the first image was taken - known as the baseline. For this acquisition a baseline of just 0.6 metres was achieved, due to very high precision spacecraft navigation. MERIS tracks algae blooms  Decaying fish carcasses are collected by a watercraft, background, in a bay south of Hong Kong Island in this Wednesday, April 15, 1998 photo. Hong Kong's fish farming industry has been devastated by red tide. Members of the Asia-Pacific Economic Cooperation agreed Friday, Oct. 16, 1998, in Honolulu to curb coastal pollution, sustain fish stocks and share research into global climate change. APEC scientists said land-based pollution contributes to harmful blooms of algae and red tide, a microscopic algae that colors the sea and is toxic to humans and marine life. Photo: AP Photo/Vincent Yu  L2-MERIS image from 12 February 2004, which shows very high concentrations of phytoplankton in Chilean coastal areas of the Pacific Ocean and in some inner areas of the region under study by Mariscope Chilena. The company is participating in a project with Chile's fish farming authority to investigate the prospect of an operational early warning system for harmful phytoplankton blooms. Images of the year  This reduced resolution (1200 metre) image shows Hurricane Isabel off the US East Coast, acquired by MERIS on board ESA’s Envisat spacecraft at 14.58 UTC on 17 September 2003. Envisat is ESA’s latest Earth Observation satellite, launched February 2002. Its orbit is a half hour ahead but otherwise identical to that of ERS-2, whose scatterometer also acquired useful meteorological measurements of the hurricane’s heart. Release date: 25 March 2004 |