BX27: LODESTAR (high aLtitude experiment On cosmic raDiation inducEd defectS in CIGS solar cells wiTh high precision meAsuRements)
Uppsala University, SWEDEN
Launch Date: October 2018
CIGS (CuInxGa(1-x)Se2) solar cells have great prospects as a thin-film photovoltaic technology due to its low mass, relatively high efficiency and low cost. A possible application of CIGS solar cells is in energy production in space, therefore it is relevant to study how CIGS solar cells degrade due to cosmic radiation influence. The primary objective of the experiment is to study the impact of cosmic radiation on CIGS solar cells. The primary objective for the flight is also the easiest objective to achieve, exposing the CIGS solar cells to cosmic radiation and collect the CIGS after flight. The secondary objectives revolve around collecting supporting data, but their success or failure will not make or break the experiment. In order to analyze radiation induced defects, the following observables will be studied before and after exposure of cosmic radiation at Uppsala University. Open circuit voltage (µV uncertainty), short circuit current (0.1fA uncertainty), capacitance, quantum efficiency (0.4 nm wavelength uncertainty), IVT and DLTS (Deep Level Transient Spectroscopy). We have performed a literature study and have not found any papers where IVT and DLTS measurement have been measured by other research groups on CIGS solar cells before and after exposure to cosmic radiation. This makes the experiment unique and of high interest to the CIGS group at Uppsala University. The measurements will be performed using high precision measuring devices from Uppsala University. In addition to this we will measure on-board temperature (2 degrees Celcius uncertainty), the total radiation counts (108 cpm/(μSv/h) uncertainty), Voc (1% uncertainty) and Isc (1% uncertainty) at regular intervals during the flight. We will also study the annealing process of the defects to determine the recovery rate. The solar cells in the experiment are placed on a horizontally facing plate to maximize the exposure. The in-flight measurements are done with arduinos which operate from a radiation shielded box. The box also contains reference solar cells protected from the radiation.
RX23 – TESOS (In-flight temperature measurement with structurally integrated fibre optic sensors)
Technische Universität München, GERMANY
Launch Date: March 2018
Rockets are exposed to thermal loads due to air friction during the flight. The characterization of these loads is crucial for the design and dimensioning of structural parts, especially when new materials are used. TESOS aims to measure the thermal loads of a REXUS rocket during the flight phase within the laminate of a newly developed carbon fiber reinforced plastic (CFRP) REXUS module. The measurement will be done by newly developed fibre optic temperature sensors. The adaption of the sensors to the REXUS requirements and their integration in the additive manufacturing process of the CFRP module are the biggest challenges of TESOS.
RX22 – GRAB (Gecko Related Adhesive testBundles)
Technical University of Braunschweig, Germany
Launch Date: 16 March 2017
In order to mitigate the growth of space debris flux rates in strongly populated orbits, it is necessary to remove objects that are considered potentially harmful from there. Such objects, like used upper stages or malfunctioning satellites, are capable of producing high numbers of fragments if hit by space debris or if an explosion occurs. A removal can be realized by an active debris removal system. Such satellites will be capable of approaching, capturing, de-tumbling and de- or re-boosting large space debris. In order to achieve contact with targeted objects, gecko-inspired adhesive materials can be utilized. The adhesive force of gecko-materials is implemented by their fungiform microstructures, that adhere to surfaces by means of van-der-Waals-forces. Currently, little is known about gecko-materials behaviour under microgravity, temperature fluctuations and cosmic radiation. The main objective of the GRAB experiment is to investigate if adhesive forces still occur in near-space environment and if so, how strong they are.
BX23 – OSCAR (Optical Sensors based on Carbon nanomaterials)
Hasselt University , Belgium
Launch Date: 7 October 2016
The OSCAR experiment aims to explore the use of novel generation carbon based (i.e. polymers, fullerenes, perovskite, diamond) optical sensors/solar cells for aerospace applications through in-situ testing during balloon flight, and complementary ex-situ testing before and after the flight to observe and understand the impact of the environment. The low mass of carbon based solar cells results in a very high power-to-mass ratio, making these devices excellent candidates for aerospace applications. Diamond based magnetometers offer a high sensitivity combined with a high robustness towards radiation and temperature. To fulfil the outlined objectives, the OSCAR experiment includes the development of a dedicated measurement methodology to study the performance and stability of organic based solar cells under extreme conditions and the development and testing of a diamond based optical magnetometer prototype for the measurement of low intensity magnetic fields in extreme stratospheric conditions.
RX20 – UB-FIRE (Universitiy of Bremen – FIre Safety Research Experiment)
Universität Bremen, Germany
Launch Date: 15 March 2016
Before materials are applied for manned space vehicles, they have to be tested regarding their flammability. Therefore e.g. the NASA-STD 6001B is used, where a flat sample is ignited. Materials which pass this test may only be used as tested. These tests are performed at terrestrial conditions (1g), which differ from manned space vehicles (0g). Another aspect is the flat sample. Realistic would be structured surfaces with corners, edges or radii. It becomes apparent that these conditions may be contradictory. In this context investigations with PMMA samples have shown that structured surfaces accelerate the flame propagation.
The goal of this experiment is to test surface structured PMMA samples and those with different core materials in microgravity and compare the results to terrestrial findings. In order to enable it, a module is designed containing compressed air bottles, combustion chambers and an IR-Camera amongst others. The recordings will be stored on a flashdrive for post flight analysis. The objective is to validate how the terrestrial investigations (1g) differ from those in microgravity (0g).
RX18 – ACTOR (Aerogel Cells Tested On REXUS)
RWTH Aachen, Germany
Launch Date: 18 March 2015
The objective of ACTOR is to test the isolating capability of cellulose aerogels under the conditons of space by measuring the heat flow during the flight with alternating pressure and temperature and comparing the results with other known isolation materials. Samples of aerogel test forms in the shape of monoliths or nonwovens are to be tested due to their insulation properties during a rocket experiment. Mechanical and chemical characteriziation of the material will be carried out before and after the flight to examine the influences of the flight conditions during the experiment. Proving cells will work with thermal sensors (K- or P-type) in order to measure temperature differences according to a German standard to compare the results to other materials.
RX16 – LOW GRAVITY (Laser Output Welding in miliGRAVITY)
Polytechnic University of Bucharest, Romania
Launch Date: 28 May 2014
Nowadays, material processing represents a wide domain and many breakthroughs were carried to develop and synthesize new materials. Therefore, this experiment came as an addition to the research made in low gravity conditions, in drop towers and during parabolic flights. Team LOW Gravity aims at designing and building an experiment that will investigate the surface deformation of alloys and metals after being melted and welded in miligravity and compare the results with those achieved under Earth-based laboratories. Our experiment is highly modular, having the LASER diode and the alloy samples as key-elements. The materials are going to be shifted during the expected 120s of miligravity, so the LASER beam will be able to melt and weld the materials. We also expect that solidification processes will occur differently in miligravity, thus we will be able to observe dendritic growth on the material surface. The alloys that will be used as samples are Ti6Al4V and acid core solder for both welding and melting. The titanium alloy will be covered with nanotubes in order to lower the reflectivity and increase the absorption of the material.
A similar experiment will be performed under Earth-based laboratory conditions, leading to a comparison between the samples modified under low gravity conditions and in SATP environment.
RX12 – REDEMPTION (REmoval of DEbris using Material with Phase Transition: IONospherical tests)
University of Bologna, Italy
Launch Date: 19 March 2012
The REDEMPTION experiment aims to test a space debris collection method which utilises bi-component poliuretanic foam, which expands and solidifies once mixed, thereby forming a solid link with anything that comes into contact with it. Space debris is an escalating problem in the Low Earth Orbit (LEO) environment, posing a threat to commercial and human space activities. According to popular opinion there is already an unstable situation developing within this region, which could lead to a degenerative event known as “Kessler Syndrome”. To avoid this, efforts are being made to reduce space debris, although a feasible system has yet to be found. The REDEMPTION project proposes using a new system based on sprayed foam that solidifies, which can be used as link between satellite and the debris, enabling re-entry of the object. It aims to test such a system by observing how these foam reagents mix together in different configurations, and the efficiency of the solidification process in terms of the mechanical properties of the foam generated by the reaction, during and after its solidification. On the basis of the results of the experiment it will be decided if this technology is worthy of further orbital nano-satellite tests.
RX10 – FOCUS (First Orbital Curing experiment of University Students)
TU München, Germany
Launch Date: 23 February 2011
The FOCUS experiment tested and evaluated a new concept for the in-orbit manufacture of space structures. To date, the fabrication of ultra-large space structures has posed a huge engineering challenge. Having a simple and reliable process to realise such structures would be valuable when it comes to applications such as solar arrays, radio antennas and solar sails. Today’s deployment technology of mast-like structures essentially relies on the unfolding of previously stowed structures; using hinges or rotational axes of minor stiffness within the structure itself as a deployment mechanism. FOCUS investigated another approach: A fibre composite space structure was launched with its resin matrix still uncured, which allowed an almost free manipulation of the flexible structure. Once deployed into its final configuration, ultra violet radiation triggered the curing process, resulting in a stiffened structure. Dual cameras monitored the deployment and curing process, and sensors were allocated to monitor temperature, pressure and UV intensity. This kind of process would not only simplify the stowage of structures, but also reduce mass due to the absence of hinges and more effective material utilisation.
RX10 – GAGa (Granular Anisotropic Gases)
Otto-von-Guericke University Magdeburg, Germany
Launch Date: 23 February 2011
The GAGa experiment performed an exploratory analysis of combined Granular Anisotropic gases. A granular gas is a dilute system of macroscopic particles interacting through inelastic collisions. Many observed processes linked to the evolution of the universe – including the formation of planets, stars, galaxies and galaxy clusters – are linked to granular gases. Liquid crystals are anisotropic fluids consisting of strongly shape-anisotropic molecules. Their phases are characterised by one- or two-dimensional order. Nematics, the simplest liquid crystals, are formed by rod-like mesogens which typically align with their axis, parallel to a preferred direction. The first of it kind, the GAGa experiment aimed to compare visual data of the combined phenomena, against theoretical predictions previously made in literature. This was achieved by filling a translucent chamber with an ensemble of rod-like particles, measuring a few millimetres in length. The box was shaken during the microgravity phase, and the particulate behaviour was measured using parallactic video images, which yielded information on the centre and orientation of the rods. From this data, granular temperatures, energy distributions and orientation correlations were identified and compared against theoretical results.