Uy.M. Urlichich, A.V. Kruglov, V.M. Vatutin, E.P. Molotov, N.E. Teploukhova, V.I. Grishin
In process of creating a communication system for the habitable base on the Mars surface for communication with the Earth one has to take into account the singularities of mutual motion of the Earth and the Mars.
When the Earth and the Moon are moving around the Sun and rotating around their axes the Earth will be seen from the territory of Martian base only over a half of the Mars revolution period (about 12 hours). During the second half the Earth will be invisible from the base territory.
Hence, the describable in the paper communication system for habitable base on the Martian surface includes two subsystems effecting the communication with the Earth by turns:
Subsystem of the base trunk communication with the Earth which provides the communication during a semi-period of the Mars rotation when the Earth is visible from the base territory;
Subsystem of satellite communication with the Earth which provides the communication during the second semi-period of the Mars rotation.
The communication of the trunk communication subsystem with the Earth is implemented via a pencil-beam rotary transceiving antenna with 10 m reflector. While Mars is rotating this antenna «sees» the Earth during the half of the Mars rotation period, at that it can effect the communication up to zero elevation.
The subsystem of satellite communication includes two repeater-satellites which are injected into Martian stationary orbits, being chosen in so way that both repeater-satellites could be seen simultaneously from the base territory.
The altitude of the stationary orbit is 17 thousand km over the Mars surface.
The communication with repeater-satellites is accomplished in Ku-band through non-full-turning antennae with 3 m reflector being a part of the relay station and located on the base territory within the common visibility zone of the both repeater-satellites.
The availability of two repeater-satellites in the communication subsystem enhances the reliability of the communication subsystem operation, increases the subsystem capacity during transmitting different data through repeater-satellites.
The satellite communication subsystem allows to solve the tasks of communication with mobile objects situated on the Mars surface (astronauts, Mars exploration rovers), at that the presence of two repeater-satellites in the system extends the zone of operation with mobile objects when they fall into the visibility zone of repeater-satellites.
The capacity of the trunk communication subsystem is more high than the capacity of the satellite communication subsystem, what is necessary to be considered when organizing the work with the habitable base.
The materials adduced in the paper show that the common capacity of the system intended for communication of the Earth with a habitable base on the Mars surface is suitable for the base normal functioning.
For effecting the data exchange with the habitable base three communication stations shall be located on the Earth near the equator spaced by 120° one from the other relative to longitude. In proportion as the Earth rotates the ground station operating with the Mars shall be substituted.