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José Fernández

Publications and source records attributed to José Fernández.

2 recordsLinked to original sources

FemtoSats for Exploring Permanently Shadowed Regions on the Moon

The recent, rapid advancement in space exploration is thanks to the accelerated miniaturization of electronics components on a spacecraft that is reducing the mass, volume and cost of satellites. Yet, access to space remains a distant dream as there is growing complexity in what is required of satellites and increasing space traffic. Interplanetary exploration is even harder and has limited possibilities for low cost mission. All of these factors make even CubeSats, the entry-level standard too expensive for most and therefore a better way needs to be found. The proposed solution in this report is a low-mass, low-cost, disposable solution that exploits the latest advances in electronics and is relatively easy to integrate: FemtoSats. FemtoSats are sub-100-gram spacecraft. The FemtoSat concept is based on launching a swarm where the main tasks are divided between the members of the swarm. This means that if one fails the swarm can take its place and therefore substitute it without risking the whole mission. In this paper we explore the utility of FemtoSats to perform first exploration and mapping of a Lunar PSR. This concept was recognized as finalist for the NASA BIG Competition in 2020. This is an example of a high-risk, high-reward mission where losing one FemtoSat does not mean the mission is in danger as it happens with regular satellite missions.

astro-ph.IM↗

Highly oriented EuO nanocrystalline films via reduction process - NIR optical response

Nanocrystalline textured EuO thin films are prepared by an oxygen loss process from a pure Eu2O3 bulk ceramic target through pulsed laser deposition in vacuum at room temperature. X-ray diffraction spectra evidence a well-defined diffraction peak corresponding to the EuO phase textured along the (110) direction. Analysis of the XRD peak profile indicates that the films are nanocrystalline (average crystallite size of 11 nm) with a compressive residual strain. The formation of stoichiometric EuO is further confirmed by a strong signal from Eu2+ in the X-ray photoelectron spectra. The complex refractive index in the near infrared has been determined by spectroscopic ellipsometry and shows that the EuO films have a high transparency (k < 10-3) and a refractive index of 2.1. A band-gap shift of 0.25 eV is found with respect to the EuO bulk. These films, deposited by an accessible and efficient method, open a new route to produce EuO films with optical quality, suitable for NIR optoelectronic components.

cond-mat.mes-hall↗