The AlfaCrux CubeSat mission description and early results

On 1 April 2022, the AlfaCrux CubeSat was launched by the Falcon 9 Transporter-4 mission, the fourth SpaceX dedicated smallsat rideshare program mission, from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida into a Sun-synchronous orbit at 500 km. AlfaCrux is an amateur radio and educational mission to provide learning and scientific benefits in the context of small satellite missions. It is an opportunity for theoretical and practical learning about the technical management, systems design, communication, orbital mechanics, development, integration, and operation of small satellites. The AlfaCrux payload, a software-defined radio hardware, is responsible for two main services, which are a digital packet repeater and a store-and-forward system. In the ground segment, a cloud-computing-based command and control station has been developed, together with an open access online platform to access and visualize the main information of the AlfaCrux telemetry and user data and experiments. It also becomes an in-orbit database reference to be used for different studies concerned with, for instance, radio propagation, attitude reconstruction, data-driven calibration algorithms for satellite sensors, among others. In this context, this paper describes the AlfaCrux mission, its main subsystems, and the achievements obtained in the early orbit phase. Scientific and engineering assessments conducted with the spacecraft operations to tackle unexpected behaviors in the ground station and also to better understand the space environment are also presented and discussed.Fundação de Apoio à Pesquisa del Distrito Federal (FAPDF), Brasil | Ref. N/

Sobre a Interpolação e o Uso nas Atividades do Programa de Pós-Graduação em Astronomia

Astronomy represents an area of scientific knowledge that constantly works with numericaldata, derived from observations (spectroscopy, photometry, polarimetry) or from physical-mathematical models. Therefore, analyzing and interpreting data of a scientific nature ob-tained from graphs and/or tables represents a very common task for the astronomer. Often,there is a need to know, for example, the coordinate of an object for a certain date (year,month, day, hour, minute and second) of observation. In other cases, during the acquisi-tion phase, extraneous processes can happen and cause the partial or total commitment ofthe desired astronomical information, which can harm a later analysis (local or global) ofthe phenomenon studied. As the Interpolation method represents a topic of study that ispart of the training process for future Masters of the Postgraduate Program in Astronomy,Professional Master’s in Astronomy (MPASTRO) of the Physics Department of UEFS, weconsider it appropriate to present a small contribution on the Interpolation method in thecontext of Astronomy. An analysis is also carried out on the skills provided for in the BNCC(National Curricular Common Base).A Astronomia representa uma área do conhecimento científico que trabalha constantemente com dados numéricos, oriundos de observações (espectroscopia, fotometria, polarimetria) ou de modelos físico-matemáticos. Portanto, analisar e interpretar dados de natureza científica obtidos a partitr da leitura de gráficos e/ou tabelas representa uma tarefa bastante comum para o(a) astrônomo(a). Muitas vezes, existe a necessidade de se conhecer, por exemplo, a coordenada de um objeto para uma certa data (ano, mês, dia, hora, minuto e segundo) de observação. Em outros casos, durante a fase de aquisição, processos alheios podem acontecer e ocasionar o comprometimento, parcial ou total, da informação astronômica desejada, o que pode prejudicar uma posterior análise (local ou global) do fenômeno estudado. Como o método de Interpolação representa um tema de estudo que faz parte do processo de formação dos futuros mestres do Programa de Pós-Graduação em Astronomia, Mestrado Profissional em Astronomia (MPASTRO) do Departamento de Física da UEFS, julgamos apropriado apresentar uma pequena contribuição sobre o método de Interpolação no contexto da Astronomia. Uma análise também é feita nas habilidades previstas na BNCC (Base Nacional Comum Curricular)

Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E$^{-2}$ shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E$^{-2}$ be able to explain the observations