Development and Testing of a Vehicle Management System for Autonomous Spacecraft Habitat Operations

As the increased distance between Earth-based mission control and the spacecraft results in increasing communication delays, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions. In addition, both near-term and future missions will feature significant periods when crew is not present, meaning the vehicles will need to operate themselves autonomously. NASA's Advanced Exploration Systems Program pioneers new approaches for rapidly developing prototype systems, demonstrating key capabilities, and validating operational concepts for future human missions beyond low-Earth orbit. Under this program, NASA has developed and demonstrated multiple technologies to enable the autonomous operation of a dormant space habitat. These technologies included a fault-tolerant avionics architecture, novel spacecraft power system and power system controller, and autonomy software to control the habitat. The demonstration involved simulation of the habitat and multiple spacecraft sub-systems (power storage and distribution, avionics, and air-side life-support) during a multi-day test at NASA's Johnson Space Center. The foundation of the demonstration was quiescent operations' of a habitat during a 55 minute eclipse period. For this demonstration, the spacecraft power distribution system and air-side life support system were simulated at a high level of fidelity; additional systems were managed, but with lower fidelity operational constraints and system behavior. Operational constraints for real and simulated loads were developed by analyzing on-orbit hardware and evaluating future Exploration capable technology. A total of 13 real and simulated loads were used during the test. Eight scenarios including both nominal and off-nominal conditions were performed. Over the course of the test, every application performed its desired functions successfully during the simulated tests. The results will inform both future tests, as well as provide insight to NASA's domestic and international partners, as they construct the next generation of space habitats to be used on beyond-Earth missions

PRODUÇÃO DE MUDAS DE PETÚNIA COMUM EM TUBETES BIODEGRADÁVEIS EM SUBSTITUIÇÃO AOS SACOS PLÁSTICOS / SEEDLINGS OF PETUNIA X HYBRIDA IN BIODEGRADABLE TUBES TO REPLACE THE PLASTIC BAGS

Objetivou-se com este trabalho comparar o desenvolvimento da petúnia nos tubetes biodegradáveis com as mudas nos saquinhos plásticos durante a fase de produção. Foram avaliados a distribuição da massa seca nas três partes da planta (folhas, caule e sistema radicular). Também foi analisado a constituição do tubete e sua perda de massa ao longo do tempo. O delineamento experimental utilizado foi de blocos intereiramente  casualizados. A análise utilizou 8 blocos com 16 parcelas em cada bloco, para saquinhos plásticos e tubetes biodegradáveis. No total 128 mudas foram utilizadas para cada embalagem totalizando 256 mudas no experimento. As médias foram submetidas à Análise de Variância, com e sem transformação nos dados e com comparações múltiplas entre as médias pelo Teste de Tukey ao nível de 5% de significância. A análise dos dados demonstrou que as mudas produzidas nos tubetes biodegradáveis apresentaram desenvolvimento significativamente menor

Assessing the overheating risks in Italian existing school buildings renovated with nZEB targets

Energy retrofit projects following nearly zero-energy buildings (nZEB) requirements often pay a little attention to Indoor Environmental Quality of the building. This aspect is extremely important in school buildings, as they are frequented mostly by young people, who are affected more by a healthy environment. In this context, starting from a reference case, overheating risks in existing school buildings considered for energy renovation were investigated through TRNSYS 16. Four building configurations were evaluated (existing, nZEB, nZEB with external shadings, nZEB with external shadings and night ventilation) and the influence of several parameters was taken into account (climate, orientation, building level). The aim of this paper is to understand if nZEB standards applied to Italian school buildings guarantee good indoor thermal conditions and which building configuration can be more advantaged by these standards. Furthermore, even if overheating risk is qualitatively recognized in insulated and air tight buildings, quantitative assessments are still missing for the Italian building stock. The intent of this research is to provide preliminary data on this topic in order to lead to a more conscious choice of retrofit strategies as a compromise between energy performances and indoor environmental quality

On the Validity of Daylight Factor for Evaluating the Energy Performance of Building

The Daylight factor is internationally recognized as the synthetic parameter to relate indoor visual task lighting requirements and daylight availability. Nevertheless, problems related within its static nature and the absence of connection with environmental parameters and geographic location, have been repeatedly highlighted in the literature. From an energy point of view, it is used in the European standard EN 15193:2008 for evaluating daylight penetration in buildings. Standard sky for D calculation (Overcast sky) has been defined as the most conservative, and from an energy point of view, this is very useful because represents the condition of peak energy consumption for artificial lighting. The aim of this study is to verify if D calculated under other sky conditions could be more conservative from an energy point of view. Whenever this case would occur, in order to keep results on the safe side, appropriate corrections should be applied to the D in the EN 15193:2008

On the built-environment quality in nearly zero-energy renovated schools: Assessment and impact of passive strategies

Indoor Environmental Quality (IEQ) is a crucial issue in school buildings, because of the conditions that pupils and students are exposed to. From this assumption, potentialities of retrofit actions with Nearly Zero-Energy Building (NZEB) targets were analyzed in existing school buildings, focusing on the impact of such measures of IEQ. Numerical analyses in a transient regime for a typical school building were carried out to assess the impacts on the thermal comfort and Indoor Air Quality (IAQ). The study took into account several building configurations and three reference cities. The results showed severe overheating risks in retrofitted schools: the operative temperature increased by several degrees with respect to the existing configuration, leading to thermal discomfort for a relevant part of the observation period. Passive techniques, namely external solar protection devices and night ventilative cooling, were applied to assess their mitigation potential. Results showed that the combination of the two solutions restored the pre-retrofit performance. CO2 levels were found to be too high for naturally ventilated buildings, regardless of the building configuration; acceptable levels might be reached only with long opening times of windows, which are unrealistic for real building operation