In order to apply for any of the following theses or internships, the candidate must have no more than 3 exams left.
At present, the orbit determination of deep space missions relies mainly on Earth-based radiometric measurements, namely ranging, Doppler, and DDOR. These are derived from the properties of the radio link between the spacecraft and one or more ground stations on the Earth. The main sources of noise affecting the radio link are: interplanetary plasma, Earth’s troposphere and ionosphere, thermal noise in the electronics.
The objective of this project is to develop a Python tool to quickly evaluate the quality of the radiometric measurements acquired at the ground stations, without the need of a detailed orbit determination analysis. The candidate will have to retrieve and load all the relevant inputs, including: radiometric measurements, meteorological data, station configuration, spacecraft telemetry. Then, the most important parameters affecting the link quality will be computed and displayed. An automatic test report will be generated.
In the context of modern methods of orbit determination in planetary exploration and radio science experiments, the use of Doppler observables is considered one of the most reliable and accurate. From an engineering point of view, one of the main parameters driving the accuracy of the orbital estimation is the reliability of the algorithms for estimating the carrier frequency of the downlink signal. Currently, the state of the art in the reconstruction of the sky frequency consists in the use of systems called Phase-Locked Loops (PLL) and spectral interpolation methods. The goal of this thesis is to use the wavelet transforms to generate the Doppler observables of spacecrafts active in deep space missions. Wavelet transforms are spectral estimators that provide a variable accuracy in the time and frequency domain, differently from the less manageable fourier transform. The candidate will use the wavelet transform libraries to compare the accuracy of said method to spectral interpolation methods. The nominal frequency will be additionally simulated and generated by the candidate, implementing SPICE kernels from JPL’s NAIF repository.
Uploaded: 15 Feb 2022/AT
Code: LT22WAVEOD
In the context of modern methods of orbit determination in planetary exploration and radio science experiments, the use of Doppler observables is considered one of the most reliable and accurate. From an engineering point of view, one of the main parameters driving the accuracy of the orbital estimation is the reliability of the algorithms for estimating the carrier frequency of the downlink signal. Currently, the state of the art in the reconstruction of the sky frequency consists in the use of systems called Phase-Locked Loops (PLL) and spectral interpolation methods. The goal of this thesis is to simulate modulated signals (i.e. containing telemetry) and to verify if the currently used frequency estimation methods are suitable in estimating the spacecrafts orbit when there is a Quadrature Amplitude Modulation (QAM). The nominal frequency will be additionally simulated and generated by the candidate, implementing SPICE kernels from JPL’s NAIF repository.
Uploaded: 15 Feb 2022/AT
Code: LT22DTLMOD
In the context of modern methods of orbit determination in planetary exploration and radio science experiments, the use of Doppler observables is considered one of the most reliable and accurate. From an engineering point of view, one of the main parameters driving the accuracy of the orbital estimation is the reliability of the algorithms for estimating the carrier frequency of the downlink signal. Currently, the state of the art in the reconstruction of the sky frequency consists in the use of systems called Phase-Locked Loops (PLL) and spectral interpolation methods. The goal of this thesis is to study and implement a generalized stochastic resonance (GSR) method to generate the Doppler observables of spacecrafts active in deep space missions. GSR methods are an innovative solution to solve the non-linear problem of frequency estimation, and their detection threshold is lower than conventional methods, making them ideal to study low signal-to-noise ratio conditions such as atmospheric ingress and egress, bistatic radar, and low SEP angles.
Uploaded: 28 Feb 2022/AT
Code: LT22GSRROD
During Solar Conjunctions, i.e. when the Sun is between the Earth and the S/C, radiofrequency TT&C links can be severely degraded. Having the Sun-Earth-Probe (SEP) angle lower than 3°, introduces deep fading events that can affect several consecutive codeword of the same signal, making communications with the S/C impossible. For this reason, it is important to increase the channel diversity (the number of independent fading levels experienced by each codeword of a transmitted signal). The objective of this project is to use interleaving techniques to increase the channel diversity and see if this can bring any improvement in the signal decoding. The candidate will work with some of the main modulations and coding techniques currently used in Deep Space Missions and test new ones. Everything will be performed using a software developed in MATLAB that is able to simulate a complete link from ground to spacecraft (and back) with the presence of the solar environment.
Uploaded: 2 Mar 2022/AZ
Code: LT22RFTTSC
In order to orbit around a remote celestial body characterized by a solid surface, optical observables which are collected by the onboard cameras are of huge importance. In particular, the images collected during the mission allow for an increased accuracy in the state of the spacecraft with respect to the target deep space object. Measurements obtained by means of radiometric techniques can be combined with optical observables to better fullfill navigation requirements and improving science return, like the estimation of the gravity field and rotational speed of the target of the mission.
This work is about the creation from scratch of the 3D geometry of different solid body types (planets, moons and asteroids) in a parametric way, to provide an input for the simulated optical observables described above. Starting from a clean 3D geometry, and by populating it with craters, riffs, boulders which can be parametrically and arbitrary modified, the student will then match the features to the real crater distribution found in literature. The results will be obtained by a photometric model, which will allow a direct coparison with images of real missions to similar space objects.
Uploaded: 2 Mar 2022/FF
Code: LT22SIMOPN
Navigation of spacecraft is mostly based on radiometric data. These consist of the information content of electromagnetic signals transmitted from the spacecraft to a tracking station. Currently, multiple networks of deep space stations exist, all of which support different space exploration missions. In this context, the receivers on the ground can be different in architecture, and provide radiometric data in different formats. These datasets can contain hours of tracking data, making them difficult to manage and transmit to radio science and navigation users. The current solution to this problem is for the tracking stations to output binary files, which are not directly readable by users. The aim of this thesis is to identify and characterize the most common dataset formats, with a focus on NASA and ESA receivers, and to create conversion scripts to make them readable and exportable to different computing languages (Python/MATLAB)
Uploaded: 25 Feb 2023/AT
Code: LT23DATARW
The Potentially Hazardous Asteroid (PHA) 99942 Apophis will make an extremely close approach (~37000 km) to Earth on 13 April 2029, so close that tidal stresses and torques may cause resurfacing or reshaping of the body and changes in its spin state.
This thesis aims to estimate the heliocentric orbit of Apophis using astrometric and radar data publicly available on the Minor Planet Center and other affiliated repositories.
The candidate will perform a literature review of the current dynamical model for Apophis, retrieve and process previous astrometric and radar measurements, and perform an ephemeris reconstruction using the ESA/ESOC flight dynamics software GODOT. This solution will then be compared with the currently available trajectories from the literature.
Uploaded: 22 Nov 2023/RLM
Code: LT23APOEPH
In the context of planetary exploration, radiometric tracking is often aided by the processing of optical images. While this methodology greatly increases the scientific return of space missions, it also increases the complexity to the orbit determination procedure, as the estimated trajectory of the spacecraft becomes a baseline for the estimation of planetary-fixed reference frames and surface features. Contrarily, optical-based navigation can be employed when using well-known features from asteroids or planetary surfaces.
The aim of this thesis is to create algorithms to read and process images acquired by past deep space missions, especially MESSENGER, from the Cartography and Imaging Sciences Node of NASA. The work will consist in developing a pipeline to extract label information from pictures metadata to query and evaluate potential correlation between images, often necessary to support the estimation of the planetary rotations. Desirable skills include Python programming, but training will be provided. This works is relevant in the context of current and future planetary exploration missions in the Mercury system, such as the BepiColombo MORE investigation of the planet.
Uploaded: 11 Mar 2024/AT
Code: LT24DPOPTP
In the context of modern methods of orbit determination in planetary exploration and radio science experiments, the use of Doppler observables is considered one of the most reliable and accurate. In this framework, orbit determination can be summarized in two subsequent steps: Initial Orbit Determination (IOD), and Statistical Orbit Determination (SOD). In particular, IOD activities are always required in the initial acquisition and definition of the spacecraft state. While SOD algorithms can effectively track spacecrafts using only Doppler observables, classic IOD methods rely only on range and angle information, which are not always available to ground operators. The goal of this thesis is to perform a systematic literature review of IOD procedures and evaluate applicability to different sets of radiometric data. Ideally, the candidate will develop and implement one or more of these methods in Python and test their effectiveness using simulated and/or real-life mission data by recovering trajectory and radiometric measurements information from the NASA PDS.
Uploaded: 13 May 2024/AT
Code: LT24DOIODA
In deep space missions, accurate navigation is critical for spacecraft to reach their destinations safely and efficiently. Limb fitting algorithms play a pivotal role in this process by precisely determining the position and orientation of celestial bodies, such as planets and moons, using their illuminated limb profiles. Aided by radiometric tracking, optical navigation procedures make spacecraft control as accurate as possible. In this context, the study of algorithms for precise centroid-estimation algorithms is crucial to assess the relative position of spacecraft around planets. The accuracy of these algorithms is usually limited by pixel resolution and observed planetary diameter.
The objective of this thesis is to perform systematic literature review to evaluate and classify limb fitting algorithms according to their suitability for mission targets, as different surface and atmospheric conditions will affect accuracy and employability. Ideally, the candidate will implement one or more of these algorithms in Python and test their accuracy using simulated and real images from flagship missions such as MESSENGER, Juno, and Cassini.
Uploaded: 13 May 2024/AT
Code: LT24LFADSN