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Projecte llegit

Títol: Reliable radio-frequency communications with spacecrafts

Estudiants que han llegit aquest projecte:

Director/a: ÚBEDA FARRE, EDUARD

Departament: TSC

Títol: Reliable radio-frequency communications with spacecrafts

Data inici oferta: 07-02-2021     Data finalització oferta: 07-10-2021


Estudis d'assignació del projecte:
    GR ENG SIS TELECOMUN
Tipus: Individual
 
Lloc de realització: EETAC
 
Paraules clau:
Plasma sheath, spacecraft, communication blackout
 
Descripció del contingut i pla d'activitats:
Ever since spacecrafts were launched into the outer space, communication schemes have been required. To this aim, ground-to-air radio-links or Data relay Satellites have been developed. These schemes of communications, though, become particularly awkward in atmospheric reentry missions, when tremendous heat builds up around the reentering shuttle. The spacecraft gets then enveloped with a sheath of ionized air that blocks communications, thereby giving rise to the so-called radio-frequency blackout. Electromagnetically speaking, the sheath of ionized air behaves as a plasma surface that attenuates the incoming Electromagnetic waves. Several techniques have been proposed to mitigate the communication blackout; namely, to name a few, the aerodynamic shaping, the magnetic windowing or the liquid quenchant injection.
In this work, the scheme of communication with airspace shuttles will be described. Also, strategies to minimize the radio-frequency blackout will be analyzed, with special emphasis on the recently proposed matching approach, which utilizes a layer surrounding the aircraft antenna to match with the plasma sheath enclosing the vehicle.
 
Overview (resum en anglès):
Radio frequency communication of space vehicles has been and continues to be one of the most critical and important points in space research. Without this system, it does not make sense to invest huge amounts of money on these flights, given that, without communication we will not be able to collect or send any type of data. Over the years, many of the communication problems have been solved, except for the problem that we will deal with in this project. That
problem is the called Blackout effect, which consists of a total communication cutoff with the spacecraft when the capsule tries to reenter atmospheres of planets amenable to ionization, such as Mars and the earth.
In this work, an in-depth study of the telecommunications systems of a space vehicle throughout history has been carried out, as well as its most recurrent problems and needs. We have focused on the communication cutoff in
atmospheric reentry and how electromagnetic waves behave when they are enveloped in plasma in those moments of disconnection. Several possible theoretical solutions to this problem have been sought and finally we have chosen the most viable one, which is to wrap the antenna with a matching layer whose electrical permittivity compensates the inductance generated by the plasma layer in communication.
Using MATLAB® software, these effects on communication have been simulated and a matching layer has been proposed that compensates the plasma and manages to establish communication with the outside. To carry out these simulations, the incidence of electromagnetic waves on the entire surface of the vehicle had to be taken into account. In our case, it has been simplified by putting the different media as concentric spheres. Once these simulations have been made, we have been able to observe that thanks to the theoretical solutions that have been proposed, it is possible to have communication through plasma, and even improve free-space radiation.
Finally, the steps to follow in this investigation have been presented. In the form of the creation of new synthetic materials with the necessary specifications to fulfill the objective of having communication through plasma.

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