SMOS

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SMOS
Type: Earth exploration satellite
Operator: European space agencyESA ESA
COSPAR-ID : 2009-059A
Mission dates
Dimensions: 658 kg (317 kg bus
with 28 kg hydrazine
and 366 kg payload)
Size: 2.4 × 2.3 × 2.3 m
Begin: November 2, 2009, 01:50 UTC
Starting place: Plesetsk Cosmodrome
Launcher: Rockot KM
Status: active
Orbit data
Rotation time : 100.0 min
Orbit inclination : 98.4 °
Apogee height :  767 km
Perigee height :  766 km

SMOS is the acronym of S oil M oisture and O cean S alinity and refers to a earth observation satellite of the European Space Agency ESA . SMOS was launched as the second satellite (as an opportunity mission, in contrast to the larger core missions) of the Earth Explorer Missions , in a long-term ESA framework program for earth observation . The first satellite in this series was CryoSat . On November 2, 2009 at 1:50 UTC, SMOS was launched into space with a Rockot rocket together with the Proba-2 probe from the Plesetsk launch site in northern Russia .

Structure and Mission

The SMOS satellite on the basis of Proteus - satellite bus has as main instrument a in the L-band operating 1.4 GHz microwaves - radiometer called MIRAS (Microwave Imaging Radiometer using Aperture Synthesis). It receives radiation in the frequency range from 1400 to 1427 MHz, which has been reserved by the International Telecommunication Union worldwide for the reception of radiation for research purposes and in which transmission is prohibited. However, the scientists had to find out that some areas of the earth were broadcasting there, and so the data from these areas could not be used. The ESA called in the competent authorities of the respective states to eliminate the radio interference . Astrium España developed and built the innovative two-dimensional microwave radiometer . The instrument consists of 69 antennas, each 165 mm in diameter and 19 mm in height, on three four-meter long arms. From the radiation received in this frequency range, statements can be made about soil moisture and salinity in the oceans. Both soil moisture and salinity are important parameters for improving global climate models and have never been measured by a satellite before. The instrument takes a hexagonal image every 1.2 seconds of an area of ​​around 1000 km².

The measurement of the near-surface salinity of the oceans with an L-band radiometer was first tested on the Skylab space station in 1973/74 with the S-194 instrument. In addition to SMOS, the Argentine mission SAC-D has been measuring soil moisture and the global salt content of the oceans since 2011. The SMAP satellite , which was successfully launched on January 31, 2015, is expected to perform similar tasks .

The satellite is supplied with energy by two solar cell booms with silicon solar cells and a combined peak output of 1065 watts, buffered by lithium-ion batteries with a total capacity of 78  Ah .

The 3-axis stabilization and orbit control is carried out using star and sun sensors , gyroscopic instruments , magnetometers and GPS as well as reaction wheels , magnetic torquers and four 1N engines.

A 2 × 20 GBit solid-state drive is available for data storage, an X-band downlink with 16.8 MBit / s for data transmission and an S-band transmission with 4 kBit / s uplink and 722 kBit / s downlink for telemetry to disposal.

Web links

Individual evidence

  1. ↑ Orbit data according to SMOS. N2YO, August 4, 2014, accessed August 4, 2014 .
  2. ↑ ESA: ESA's water mission SMOS. February 12, 2009, accessed March 16, 2009 .
  3. ↑ a b SMOS satellite successfully started. DLR, November 2, 2009, accessed April 8, 2014 .
  4. ↑ SMOS water mission winning battle with interference. ESA, October 6, 2010, accessed October 8, 2010 .
  5. ↑ Mark Drinkwater:Exploring the water cycle of the 'Blue Planet'. The Soil Moisture and Ocean Salinity (SMOS) mission.(PDF file; 1.21 MB) ESA Bulletin No. 137, February 2009.
  6. ↑ SMOS data sheet (PDF file; 698 kB)