Orbital debris of approximately 10 cm in size can be measured with ground-based telescopes. This debris threatens the functioning of satellites and has an impact on the economy and the global security of space activities. In the GEO orbit, where most of the economically active satellites are located, exists approximately 842 cataloged debris. On the other side, orbiting LEO exists approximately 13485 debris cataloged. In this context, the  ESA studies show that hundreds of millions of small objects over 1 mm are currently in the two orbits GEO and LEO above the Earth and have not yet been cataloged. In this study, we created a computational procedure to detect space debris in GEO orbit based on images obtained from ground-based telescopes on the static mode. In this mode,  the field sky stars appear as lines in the CCD images and the garbage in the form of dots.  CCD images of 2992 x 2092 pixels (high resolution) and with 5 degrees of field of view (FOV) and with 7 seconds of exposure used in this work were obtained with the PanEOS telescope (Panoramic Electro-Optical System), 750 mm aperture, and installed at the Picos dos Dias observatory of the National Astrophysics Laboratory (LNA). For this research, we adapted the Photoutils package written in Python to build a mask and separate stars from candidates for space debris. Our methodology consisted of first smoothing the images using a Gaussian Kernel filter, then each element was categorized into two categories, and finally, the stars were erased resulting only in space debris candidates. We tested combinations of flow to establish the detection limit and used the different points spread function (PSF) to determine the limit of the elongation of objects. Our methodology works with a single image at a time in a fast and efficient way.  This allows us to detect objects with different PSF and therefore requires low hardware capability. Our results in this validation phase identified 100% of the artificial training debris. In the real images of the PanEOS telescope, we detected a few real debris consistent with the  expected size. In the next steps, we must estimate the size of the object and characterize its orbit.

This Master's Dissertation presents a preliminary design of an aerospace vehicle, using hypersonic airbreathing propulsion based on supersonic combustion (scramjet technology), for atmospheric flight at 20 km altitude, at hypersonic speed, corresponding to Mach number 5.79. Scramjet is an aeronautical engine without moving parts, where the aerospace vehicle integrated with scramjet technology (propulsion system) must be coupled to a rocket engine. The current means of access to space is limited by the chemical propulsion system (solid and / or liquid fuel) carried onboard rockets. The technology of supersonic combustion (scramjet) is being studied as an airbreathing propulsion system, to be used in the dense layers of the Earth's atmosphere, to access space. A demonstrator is being designed to be coupled to the Sonda III rocket engine, to operate as a second stage, starting the operation at 20 km altitude. The theory of oblique shock waves, the theory of heat addition in one-dimensional flow (Rayleigh's theory) and the theory of expansion waves (by Prandtl-Meyer) coupled to the area ratio are applied in the design of the compression sections, of combustion and expansion, respectively, of the scramjet demonstrator with internal admission configuration. Steady state, one-dimensional flow and air under calorically perfect gas conditions will be considered. Thermodynamic properties (pressure, temperature, density, speed of sound) and flow velocity (Mach number) will be presented along the streamline from the leading edge to the trailing edge of the demonstrator, considering flow without and with boundary layer effects, for the conditions of no fuel burning (power-off) and fuel burning (power-on). Finally, the conceptual design and a brief approach to systems engineering in the development of a nanosatellite launch vehicle are presented.

Atmospheric conditions are mostly driven by the Sun, which follows a cycle of activity whose duration is about 11 years. Since this cycle has been found out, researchers has brought up the hypothesis that it may have some influence at the lower atmosphere, taking as proxies the Carbon-14 and Berilium-10 concentration in tree rings and ice cores. Beside that, some manuscripts have shown that, during the Maunder Minimum, where the Sun were at minimum of activity, some regions over the globe experienced a tiny "Ice Age". Initially, it was believed that this influence was related to the Total Solar Irradiation variation during a cycle. Although, further studies have shown that such variations were a rather small to produce these variations on the lower atmosphere. So, they have created the hypothesis that these influence was related to the solar cycle on the Galactic Cosmic Rays (GCR) flux through the heliosphere. GCR work as a ionizing agent, favoring the aerosol synthesis, which acts as Condensation Nuclei, which favors clouds formation. So, the objective of the research was to find a correlation between the solar cycles and meteorological conditions in the region where the cities of Rio de Janeiro e São Paulo are located. In this region, a huge flux of aircraft is observed.

Under the development of new technologies, the Aerospace Engineering is increasingly
improving its equipments in order to assist exploration that goes beyond our Heliopause.
As an example of this we can cite the launch of the space artfact Transiting Exoplanet Survey Satellite
(TESS) that has been contributing photometric data to Space Sciences, like Astrophysics,
with the aim of study various physical phenomena. As an exemple, the magnetic activity
of stars can be fundamental in forming the atmosphere of exoplanets and impact your
habitability as well as, it can trigger life in the orbit of type K and M stars, which are
considered to be cold and they are the most numerous in the main sequence phase in
the Hertzsprung-Russell diagram. Based on these investigations and through statistical
analysis of the behavior of stellar flares in relation to their classi cations, rotational periods
and spectral subtype, this dissertation presents a study on the variation of energie
of stellar flares as a function of their rotational period in a sample of 679 TESS stars of
spectral type K and M. None of the stars in this sample showed a correlation between the
energy of their surface stellar eruptions as a function of their rotational period. Finally
we present four scenarios involving the stars and their stellar eruptions and theirs that
can explain our results.

A first study used the hidden Markov model in this dissertation to describe the daily rainfall occurrence and intensity at four meteorological stations in the Metropolitan Region of Fortaleza in the Northern Northeast Brazil (NNB) and the teleconnection patterns that influence precipitation regime during the rainy season (February, March, April, and May) from 1975 to 2013. A model with four hidden states was associated with climatic conditions: very rainy (1), rainy (2), less rainy (3), and dry (4), satisfactorily agreeing with the interannual variability of the rainy season in this region. State 2 was the only one that showed a statistical trend, indicating a probable decrease in the occurrence of precipitation in the rainy season. It was also shown that the meteorology associated with states 2 and 4 is strongly related to the El Niño-South Oscillation and the North Atlantic tripole and is intrinsically conditioned by the large-scale atmospheric patterns of the Northern Hemisphere. All of these mechanisms modulated the displacement of the Intertropical Convergence Zone (ITCZ) southward (state 2) or northward (state 4), affecting the occurrence of precipitation in the NNB. State 1 was distinguished by the influence of the Atlantic Meridional Mode and the ITCZ displacement further south, while state 3 was identified by the absence of teleconnection patterns. A second study investigated the homogeneity and trend of eleven extreme precipitation indices from a daily data set of 84 rain gauges in the state of Ceará, located in the NNB, from 1974 to 2018, on the annual and seasonal time scales. The data were initially submitted to the gap-filling and quality control processes. Most precipitation series were classified as "useful," and dry day precipitation indices were more susceptible to breaks than rainy day variables for homogeneity. The significant break years in the series agreed well with the El Niño and La Niña events, suggesting a further investigation of this possible connection. The precipitation indices for rainy and dry days presented mostly decreasing and increasing trends, respectively, indicating a decline in the rainfall regime in Ceará, mainly in the central-eastern, northwestern, and southern regions, in the annual and rainy seasons. The LOWESS curve showed changes in almost all series during the 1980s and 1990s, coinciding with the homogeneity breaks and the years of severe droughts in the region. The correlation coefficients were strong and significant between all precipitation indices and the other variables, seeming to induce changes in total rainfall.

Current rocket engines have a low specific thrust compared to the airbreathing propulsion technologies. Airbreathing supersonic combustion engines/vehicles are an alternative to improve the efficiency of access to space in a flight through the dense Earth’s atmosphere, below 60 km of geometric altitude. In this work, aerodynamic analysis of the conceptual model of supersonic combustion engine/vehicle (scramjet) was carried out to operate as a second-stage propulsion engine of a nanoSats launch vehicle. Two engineering approaches, analytical and computational numerical methodology, were used to perform the preliminary analysis of the proposed scramjet model, coupled to the third propulsion stage, at an altitude of 20 km with flight speed equivalent to Mach 5.8. Atmospheric air was considered a calorically perfect gas, and the viscous effects were neglect in a preliminary analysis. Supersonic combustion was modeled as heat adding to the supersonic flow without fuel injection. Then, numerical simulations were carried out considering the effects of the boundary layer development to verify the aerodynamic feasibility of the model. Optimization of the compression angles at the scramjet compression section was used to minimize the entropy generation and increase the vehicle’s compression efficiency, aiming to reach the temperature and Mach number at the combustion chamber entrance. The temperature required at the combustion chamber entrance is estimated to self-ignite the air-fuel mixture. Korkegi limit was evaluated through oblique shock waves in the compression section and in the heat addition process. Using the Korkegi limit, in the preliminary analytical design, as an indication of unstart due to the separation of the boundary layer caused by the adverse pressure gradient, we investigated to identify in numerical simulations considering the viscous effects whether the unstart phenomenon would occur. Numerical simulations were performed using commercial software, ANSYS Fluent, using the turbulence model known as transition SST. We also performed mesh convergence tests, numerical experiment validation on top of numerical data validated by HyShot flight data. Both meshes used in the validation and the analysis of the present work have equivalent levels of refinement in the direction of the wall, satisfying the condition of the turbulence model (𝑦+ < 1). The analytical calculations showed good quantitative and qualitative consistency with the numerical simulation results considering the same simplifications adopted in the analytical. An adaptation of the analytical method is proposed to take into account the effects of the interaction of the expansion fan with the oblique shock wave incident on the compression section of the scramjet. The results of the viscous simulations indicated that should be made improvements in the geometry due to the low temperature at the combustion chamber entrance, as well as reduced mass flow captured by the combustor, as a consequence of solution used to prevent unstart.