Space environment

Résumé

Space environment is a branch of astronautics, aerospace engineering and space physics that seeks to understand and address conditions existing in space that affect the design and operation of spacecraft. A related subject, space weather, deals with dynamic processes in the solar-terrestrial system that can give rise to effects on spacecraft, but that can also affect the atmosphere, ionosphere and geomagnetic field, giving rise to several other kinds of effects on human technologies. Effects on spacecraft can arise from radiation, space debris and meteoroid impact, upper atmospheric drag and spacecraft electrostatic charging. Radiation in space usually comes from three main sources:

The Van Allen radiation belts

Solar proton events and solar energetic particles; and

Galactic cosmic rays.

For long-duration missions, the high doses of radiation can damage electronic components and solar cells. A major concern is also radiation-induced "single-event effects" such as single event u

Source officielle

https://en.wikipedia.org/wiki/Space_environment

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (3)

Publications associées

Chargement

Personnes associées

Chargement

Unités associées

Chargement

Concepts associés (12)

Concepts associés

Chargement

Cours associés (4)

Space environment is different from what we can experience on Earth, requiring specific design approaches in order to achieve reliable operations. Engineers must hence face new challenges stimulating their creativity to tackle those particular constraints.

This course is a "concepts" course. It introduces a variety of concepts in use in the design of a space mission, manned or unmanned, and in space operations. it is at least partly based on the practical space experience of the lecturer.

The main objective of the course is to introduce the concept of space system design and engineering. The course will describe the various subsystems involved in the design of a satellite. It will also describe the techniques of systems engineering that are used to obtain a coherent satellite design.

Afficher plus

Cours associés

Chargement

Séances de cours associées (9)

Séances de cours associées

Chargement

, ,

FPGAs (Field Programmable Gate Array) are an attractive technology for high-speed data processing in space missions due to their unbeatable flexibility and best performance-to-power ratio in comparison to software. However FPGAs suffer from 3 major drawbacks: (1) higher programming effort is required with respect to software; (2) hardware resources need to be allocated for each implemented function in contrast to software functions which can be executed on the same processing hardware; and (3) FPGAs are required to adopt radiation hardening techniques when deployed in a space environment. This paper presents a reconfigurable platform that demonstrates how modern FPGAs can be considered as computing resources like any other, suitable for emerging spatial applications and not subjected to the above-mentioned drawbacks. In particular, we show that large FPGAs can be split in different regions containing concurrently-running accelerators which can support the execution of a single or multiple applications. Then, in the same way as software-based multiprogrammed and multithreaded systems can dynamically create, schedule and execute threads, FPGA-based accelerators can be swapped in and out according to scheduling needs by exploiting their dynamic partial reconfiguration capability. A proof of concept cloud detection algorithm for Sentinel-2 multispectral images has been implemented and tested on our platform to validate the system's design principles and performance.

IEEE2018

Chargement

High Power SMA Connectors

Michael Mattes, Francisco Edén Sorolla Rosario

On board of satellites traditionally Travelling Wave Tube Amplifiers (TWTAs) together with standard waveguide technology were used for transmitters in telecommunication payload systems. With the advent of Solid State Power Amplifiers (SSPAs) printed circuit board (PCB) technology became also attractive for the output stages of these high-power transmitters with the advantage of smaller size, lower weight and higher integration density. In a power combining circuitry the PCBs have to be interconnected by phase stable coaxial cable assemblies with suited connectors. Although SMA RF connectors are preferred in space telecom missions because of their light weight and small size this type of connector has serious limitations in terms of the required RF power handling. Therefore in these high power sections, one is still forced to use the often bulky TNC connectors. Under the ESA activity ”High Power SMA Connectors” a European consortium has been created for the investigation of small size high power coaxial connectors that will be optimized with regard to RF-breakdown, Corona, Multipactor and PIM effects as well as thermal power dissipation making them applicable in satellite transmitter stages. The goal is the development of a new family of high power SMA connectors capable to withstand power levels of at least 50W CW in space environment to match the levels delivered by the new generation of Solid State Power Amplifiers. The research is manifold: First, suitable theories of PIM, corona discharge und multipactor in coaxial structures have to be established or adapted from known similar (waveguide) problems. Second, the power limiting effects in SMA connectors like the internal air gap have to be identified and eliminated by appropriate changes of the connector design. Third, suitable materials for the individual parts and the manufacturing process of the new high power SMA connectors have to be analysed and selected. The activity started with a deep literature research of the state of the art of the interesting phenomena followed by first suggestions of the basic design of a high power SMA connector. At the workshop we will report on the status of the project and on the achieved results.

2008

Chargement

Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating

Jonathan Marc Philippe Faustin, Yu Lin, Henri Weisen

We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed three-ion scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of He-3 ions to high energies in dedicated hydrogendeuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast He-3 ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, He-3-rich solar flares.

Nature Publishing Group2017

Chargement

High Power SMA Connectors

Michael Mattes, Francisco Edén Sorolla Rosario

2008