page_title: Nanosat 01
section_title: Earth magnetic nanosensor
hierarchical_section_title: Nanosat 01 / Experiments / Earth magnetic nanosensor
context_page_description: The Nanosat 01 was an artificial satellite developed by the Spanish Instituto Nacional de Técnica Aeroespacial and launched the 18th of December 2004. Considered a nano satellite for its weight of less than 20 kg, its main mission was forwarding communications between far reaching points of the Earth such as Juan Carlos I Antarctic Base from mainland Spain. This was possible due to its polar orbit and altitude of 650 km above sea level. During an operational run the data obtained in the Antarctic would be uploaded to the satellite during its fly by and then, downloaded in Spain when satellite reached the Iberian Peninsula.
  When its service life came to an end in 2009, it was replaced by the Nanosat-1B, also developed by INTA.
context_section_description: As a prove of concept, INTA designed and developed a magneto-optical compass based on the Faraday effect capable of  accurately measure Earth's magnetic field. The centerpiece of the device was a Sol–Gel Faraday rotor, consisting in several rods of a dispersion of γ-Fe₂O₃ nanoparticles (less than 15 nm in size) suspended in an amorphous silica lattice. These rods were stacked inside a polarimetric dome (itself being composed of several layers of polarizers) responsible of directing light beams produced by a LED towards the rods longitudinally. When the light propagated inside the rods along their axis, the magnetic field created by the austenite nanoparticles would interact with it causing the rotation of the polarizers. This rotation would be perceived as change in the intensity of the light measured by four photodiodes allocated new to the exiting end of each rod. The data collected by the photodetectors would then be processed in the OBDH which was capable of providing accurate readings (up to 10 nT) on both the satellite's attitude and the value of the geomagnetic field.
  The usage of the silica / γ-Fe₂O₃ composite was driven by the search of a material capable of providing good mechanical properties with a high degree of transparency, high Verdet constant and superparamagnetism in order to avoid remnant magnetism and facilitate measuring the intensity of the light.
  In addition, it contained several coils designed to compensate possible variations of Verdet constant due to changes in temperature or wavelength inside the sensor. And a stabilized power source for the LED. Both subsystems were also used when calibrating the sensor midflight. The device had a diameter of 20 mm and less than 5 mm in thickness with a total weight of 200 g with less than 2 W of power consumption.
  Its conception was the result of more than 7 years of joint research between the Instituto de Ciencia de Materiales de Madrid (ICMM subdivision of the CSIC) and INTA. It was reported that represented the first application of a Sol–Gel based technology in the aerospace industry and an important step forwards in further miniaturization of the satellites.
caption: Faraday effect.
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