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Projecte llegit

Títol: Design of a Mission to Characterize Thermospheric Density

Estudiants que han llegit aquest projecte:

Director/a: GIL PONS, PILAR

Departament: FIS

Títol: Design of a Mission to Characterize Thermospheric Density

Data inici oferta: 05-02-2026     Data finalització oferta: 05-10-2026


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: EETAC
 
Segon director/a (UPC): PIÑÓN MEDIERO, JORGE
 
Paraules clau:
Thermospheric Density VLEO Femtosatellites Differential Drag Sequential Deployment IOD
 
Descripció del contingut i pla d'activitats:
Over recent years, the number of satellites in low Earth orbit (LEO) has grown exponentially. The thermosphere plays a key role in their atmospheric reentry and is also critical for telecommunications. Consequently, there is significant interest in assessing its properties through frequent, real-time measurements. The resulting data will enhance model quality and improve reentry predictions.

The primary objective of this Engineering Degree Thesis is to design a mission for the characterisation and parameterisation of this atmospheric layer. The work encompasses the complete design of spherical femtosatellites-including their components-with special emphasis on the payload, namely highly sensitive accelerometers, GNSS receivers, and magnetometers. It also includes the detailed definition of all mission phases.

The design process will involve a comprehensive feasibility analysis of various mission options, evaluating realistic simulation budgets for components and payload, making key mission decisions, and conducting power and communication link budget analyses. Furthermore, all mission phases will undergo thorough risk identification and assessment.

The project's final deliverable will be a complete theoretical plan for an In-Orbit Demonstration (IOD) mission focused on thermospheric measurement. The work will aim to progress to the development of an Engineering Model (EM), subject to feasibility.
 
Overview (resum en anglès):
We propose the design of a mission to characterize the thermospheric density in very low Earth orbit (VLEO). Our understanding of thermospheric density is affected by large uncertainties, which in turn translate into uncertainties in aerodynamic drag, one of the dominant perturbations affecting satellite operations and orbital prediction. Despite the increasing interest in VLEO missions, the availability of in-situ measurements in these regions remains limited, leading to significant uncertainties in orbit propagation, re-entry prediction, and space traffic management. Improving the experimental characterization of this region is therefore increasingly relevant for both scientific research and future VLEO operations.

To address this problem, the mission proposes a low-cost swarm of femtosatellites capable of performing distributed measurements of the lower thermosphere. The measurement methodology is based on drag sensing, using the orbital deceleration experienced by satellites with low ballistic coefficients to indirectly estimate atmospheric density. The use of multiple satellites also enables measurements to be distributed in both space and time, improving the representativeness of the collected data.

The proposed architecture relies on a passive sequential deployment strategy, in which satellites are progressively released using autonomous burn-wire mechanisms and differential drag effects. This approach increases temporal coverage and extends the observation window without requiring active propulsion or complex attitude control systems. In this way, atmospheric drag is not only treated as a disturbance, but is also exploited as a useful mechanism for mission deployment and orbital separation.

The mission combines simplicity, redundancy, and distributed sensing to provide experimental thermospheric density data in VLEO, while simultaneously validating low-cost swarm architectures for future atmospheric and space weather monitoring missions. The proposed demonstrator is intended to serve as a first step toward more extensive future distributed measurement missions in the lower thermosphere.

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