Attitude system

of the first Russian technological nanosatellite TNS-0

A.A.Ilyin, N.V.Kupriyanova, M.Yu.Ovchinnikov

Keldysh Institute for Applied Mathematics of RAS

Miusskaya Sq., 4, Moscow, 125047, Russia

V.I.Penkov

Moscow Aviation Institute,

Volokolamskoe Shosse, 4, Moscow, GSP-3, 125993, Russia

A.S.Selivanov

Russian Institute of Space Device Engineering

Aviamotornaya St., 53, Moscow, 111024, Russia

 

The main purpose of the nanosatellite TNS-0 mission is to collect an experienc in spacecraft control technology through global communication network GLOBALSTAR usage or a similar. Satellite becomes system's subscriber and it enables to download to a satellite and receive information using standard equipment for global communication. Limitations in connection duration and in time that connection is possible to establish appear.

The satellite is developed and constructed by the Federal State Unitary Enterprise "Russian Institute of Space Device Engineering". Its attitude control system is developed the by Keldysh Institute for Applied Mathematics RAS. According to its construction and functional content the nanosatellite TNS-0 belongs to the class of primary spacecraft.

The satellite is equipped with the passive magnetic attitude control system providing an orientation of its longitudinal axis along the local intensity vector of the geomagnetic field. Attitude control system consists of the permanent magnet and two sets of hysteresis rods. We consider problems arising during realization of such a system, and ways to solve the problems.

The satellite was successfully launched from the International space station in March, 2005.

Measurements through GLOBALSTAR network were taken in the on-line mode and passed these time moments when satellite contact was possible to establish, or in the process of connection it was possible to assign another measurements program allowing to storage sensor readings during single pass (no more than 1000) and receive its next communication session.

To determine current orientation we use readings of three sun sensors. We consider geometrical and statistical methods taking into account the specificity of the problem.

In the paper we present the model of motion of a fast rotational satellite with passive magnet and hysteresis rods to be used for one orbit and the model of satellite's motion, according short-time measure sessions. We obtained stationary angler motions of the satellite and analyzed its stability.

We suppose the location of satellites in space is known each moment. To interpret the readings of sun sensors we take into account the albedo of Earth. The data of each measure sessions are analyzed particularly. Firstly, the preliminarily geometrical analysis is done. The program complex is adopted to each measure sessions depending on accepted model and number of determinate parameters and also on the possibility of preliminarily geometrical estimation.

We describe the attitude system of the first Russian nanosatellite TNS-0. We solved problems appeared during realization of the passive magnetic attitude system. They are as follows: providing of restoring and damping torques, arrangement of elements of the system within the satellite body.

It was introduced the model of motion of the satellite with the permanent magnet and hysteresis rods. We used the averaged geomagnetic field model. In the case of the short-time session the Euler motion of a rigid body was determined. We obtained the stationary solutions of angular motion and investigate asymptotical stability of the stationary solutions.

We determined the angular motion of the satellite by measurements obtained during the whole orbit and successfully compared it with the stationary motion mentioned above.