Search

Observations that require large physical instrument dimensions and/or a considerable amount of cryogens, as it is for example the case for high spatial resolution far infrared astronomy, currently still face technological limits for their execution from space. The high cost and finality of space missions furthermore call for a very low risk approach and entail long development times. For certain spectral regions, prominently including the mid- to far-infrared as well as parts of the ultraviolet, stratospheric balloons offer a flexible and affordable complement to space telescopes, with short development times and comparatively good observing conditions. Yet, the entry burden to use balloon-borne telescopes is high, with research groups typically having to shoulder part of the infrastructure development as well. Aiming to ease access to balloon-based observations, we present the efforts towards a community-accessible balloon-based observatory, the European Stratospheric Balloon Observatory (ESBO). ESBO aims at complementing space-based and airborne capabilities over the next 10-15 years and at adding to the current landscape of scientific ballooning activities by providing a service-centered infrastructure for broader astronomical use, performing regular flights and offering an operations concept that provides researchers with a similar proposal-based access to observation time as practiced on ground-based observatories. We present details on the activities planned towards the goal of ESBO, the current status of the STUDIO (Stratospheric UV Demonstrator of an Imaging Observatory) prototype platform and mission, as well as selected technology developments with extensibility potential to space missions undertaken for STUDIO. Copyright © 2020 by the International Astronautical Federation (IAF). All rights reserved.

PoGO is a stratospheric balloon project with a cosmic ray experiment from KTH, Stockholm, Sweden. The PoGO+ mission was launched on July 12th, 2016 for a 7 day flight from Sweden to Canada. The payload mass was 1728 kg and an Aerostar SF-39.57 balloon was used to reach the float altitude of 40 km. In 2013 a similar experiment flew from Esrange to Norilsk in Russia in a circumpolar flight that lasted 2 weeks. That balloon mission was called PoGOLite. The experiment on PoGO+ was a balloon-borne hard X-ray polarimeter operating in the 25 - 240 keV energy band from a stabilized observation platform. Observations were conducted from a stabilized stratospheric balloon platform at an altitude of approximately 40 km. The primary targets were the Crab - a pulsar and associated wind nebula in the constellation of Taurus, 6500 light years from Earth, and Cygnus X-1 - a black hole binary system. A custom attitude control system kept the polarimeter field-of-view aligned to targets of interest, compensating for sidereal motion and perturbations such as torsional forces in the balloon rigging. After a launch at 03:17 UTC, the balloon reached float altitude after more than 5 hours, due to a cold stratosphere with slow ascent. A slower than anticipated wind took the balloon over the Atlantic for a landing in Canada on July 18th at 22:26 UTC. Landing latitude was 71.84747 N, longitude 110.885 E on Victoria Island. The mission was very successful with all systems both scientific and support and balloon systems working nominal during the complete flight. A huge amount of scientific data was collected during the flight that are analyzed. The landing and recovery was performed nominal and the scientific data were recovered and delivered to the science team within 12 days after landing. The mission was managed by SSC and SSC was also responsible for the gondola structure, housekeeping and communication systems, power systems and of the balloon flight systems. SSC was handling the launch, QC 20170816

Thick 4H-, and 6H-SiC epitaxial layers have been grown by LPE from Si-Sc-C solvent at microgravity conditions during a space experiment, as well as on-ground. The samples are characterised by cross-sectional TEM and HRXRD. Layers grown at microgravity are relatively defect free, although their surfaces are always stepped. Control samples grown on-ground have similar surface appearance, but contain scandium carbide precipitates, nanopipes, micropipes and/or cavities as verified by TEM. However, none of the aforementioned defects was traced in the layers grown at microgravity conditions. So, samples grown at space microgravity conditions are superior in their defect structure to those ones grown on the ground. The defects called nanopipes can be described as empty pipes of about 200 nm diameter traversing the layer in the [0001] (growth) direction. The steps in the microgravity and on-ground samples have facets of {104} type crystallographic planes both in 6H-, and 4H-SiC. We suggest, that those facets are formed and preferred during growth due to a possible mechanism of decreasing the high energy of the growing Si terminated (0001) surface. (C) 1999 Elsevier Science S.A. All rights reserved.

High quality, hexagonal SiC layers have been grown in microgravity conditions and on-ground as well. The surface of the layers is always stepped. The dislocation density of the layers is increased closer to the surface. Scandium carbide precipitates, nanopipes and cavities were found in the SiC layers grown on-ground, but none of them were traced in the layers grown under microgravity conditions.

6H and 4H polytype silicon carbide (SiC) layers have been grown on ground and under microgravity conditions by liquid phase epitaxy (LPE) from a solution of SiC in Si-Se solvent at 1750 degrees C. The effects of gravity on the growth parameters and material characteristiques have been studied. The growth rate, Sc incorporation, and the structural defects are modified in reduced gravity conditions, while the polytype reproduction of the substrate is not affected. The results obtained are intriguing as to further experiments providing objects for carrier lifetime measurements., NR 20140805

QC 20100528