Attitude dynamics of the first Russian nanosatellite TNS-0

Paper number

IAC-06-C1.1.06

Author

Prof. Michael Yu. Ovchinnikov, Keldysh Institute of Applied Mathematics, RAS, Russia

Coauthor

Mr. Andrey Ilyin, Keldysh Institute of Applied Mathematics, RAS, Russia

Coauthor

Dr. Michael Yu. Ovchinnikov, Keldysh Institute of Applied Mathematics, RAS, Russia

Coauthor

Prof. Arnold Selivanov, Russia

Coauthor

Mrs. Nadezhda Kupriyanova, Keldysh Institute of Applied Mathematics, RAS, Russia

Year

2006

Abstract

The attitude dynamics of the first Russian nanosatellite TNS-0 is considered. TNS-0 was manually launched from the International Space Station in March, 2005. The satellite was equipped with a magnetic attitude control system comprising a strong permanent magnet mounted along the satellite symmetry axis and a number of hysteresis rods. It was expected the satellite symmetry axis to follow the induction vector of the geomagnetic field. When the satellite has been put into the orbit, its angular momentum was too high. In contrary to expectations TNS-0 became fast-rotating body interacting with the geomagnetic field. To interpret an actual motion of the satellite is a purpose of the paper.

To determine the satellite attitude motion three elementary sun sensors were installed on the TNS-0 corp. Initally at each communication session the downloaded sun sensor measurements comprised a several minutes only. The data analysis showed that the satellite angular velocity decreases in a way as it has to be for a body equipped with hysteresis rods. After several sessions the satellite was lulled to sleep for a certain time to avoid the battery energy dissipation.

When the satellite has been woken the mode of a measurement collection was changed to obtain sun sensor measurements along a whole orbit. Analysis of the measurements showed that the satellite has probably approached the following motion: the satellite fast rotates; the magnet direction precession-averaged follows the induction vector of the geomagnetic field; the angle between the magnet and the induction is not rather small. The analytical research of the motion is carried out.

Firstly, the dynamics of a body with a permanent magnet only is considered. For the precession-averaged equations the two stationary solutions exist. The first stationary solution corresponds to the motion when the momentum follows the geomagnetic induction vector, and the second one corresponds to the motion when the momentum follows an opposite vector. Both stationary solutions are stable, however, there is no their asymptotical stability. To examine the asymptotical stability of solutions the approximating model of the hysteresis was involved. Thus, two motions are asymptotically stable but the single value only of the nutational angle corresponds to the stable solution. The equations analysis shows that in such a motion a spin rotation of the satellite does not decrease despite the hysteresis rods effect. The analytical research approved the experimental results which were obtained by sun sensors data processing.

The work has been supported by the Russian Basic Research Foundation and the Russian Agency of Science and Innovations.

Abstract document

IAC-06-C1.1.06.pdf

Manuscript document

IAC-06-C1.1.06.pdf (🔒 authorized access only).

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