Materials Science

RX30: IMFEX (ISRU MoonFibre Experiment)

RWTH Aachen University, Germany

Launch Date: 29 March 2023

Space industry experience renewed interested to return to the Moon. One of the goals of NASA’s Artemis project is to establish a permanent lunar settlement by the year 2028. Other entities aim to mine lunar resources, perform scientific experiments and send tourists to the Moon. All of these initiatives share a common bottleneck,  which are very high launch costs. In order to minimize the costs, equipment should be produced on the Moon as much as it is possible by using local materials. One type of materials that can be produced are fibre-based materials, which are used extensively on Earth and will find various usages on the Moon as well. The MoonFibre project of RWTH Aachen University aims to develop a technology that can produce such materials from lunar regolith using only energy as input. The In-situ resource utilization MoonFibre EXperiment (IMFEX) fits this bigger MoonFibre picture by being the first experiment to prove that spinning fibres in microgravity is possible, as this has never been done before. Optimal spinning parameters will be determined and mechanical properties of created fibres compared to their terrestrial counterparts. Results of this experiment are crucial input for development of future fibre-spinning facilities on the Moon.

RX29: HERMESS (Hull applied ElectroResistive MEasurement of Structural Strains)

Bundeswehr University Munich, Germany

Launch Date: 01 April 2023

HERMESS (Hull applied ElectroResistive MEasurement of Structural Strains) is an experiment of the Bundeswehr University Munich dedicated to gaining a deeper understanding of the mechanical strains occuring within a rocket body during flight.
Even in the age of modern rocketry, the exact range of mechanical strains in rocket bodies remains difficult to characterize, as these flight loads currently are estimated using semi-empiric aerodynamic modelling experiences which can not perform with satisfying precision.
The ambition of HERMESS is to gain knowledge about the real flight loads present in the structure and can therefore contribute to advancing the optimization of rockets. A better understanding of the real strains occurring in the structure allows lightweight engineering approaches that can lead to a better use of material, reducing mass and thereby costs.
Hereby new perspectives for rocket design are opened, furthermore countermeasures against risks that can possibly provoke a launch failure due to mechanical overloads can be assessed.
The strains, encompassing several forces and torques, can be calculated starting from measurements with electroresistive gauge strains that will feed signals to the system throughout the flight phase and later on will be subjected to a profound analysis process.

RX29: S Cephei (Suspension of Carbon Nanotubes under dielectrophoretical Influence)

Technical University of Dresden, Germany

Launch Date: 01 April 2023

The field of application of carbon nanotubes (CNTs) is very versatile due to their special thermal, electrical and mechanical properties. They can be used to develop materials for ESD and EMI protection, sensor technology and mechanical reinforcement, which opens up a wide range of applications in industry and research.
For this it is necessary to understand the basic properties and thus make them accessible for manufacturing processes. Since the properties are largely dependent on the alignment of the CNTs, it is essential to understand the alignment process in detail.
“S Cephei” will therefore observe and document this process while using the REXUS platform to exclude gravitational influences during the microgravity phase of the flight. The alignment is achieved in the experiment by dielectrophoresis as a result of an electric field, whereby the electric field is caused by applying an alternating voltage to a capacitor. This process is influenced by temperature, viscosity of the suspension, frequency and amplitude of the alternating voltage, and the type and quantity of CNTs [11]. Several cameras are used for documentation, which allows a three-dimensional model to be generated by software, thus improving the understanding of the process.

BX31: MASS (Manufacturing of Structures in Space)

Hochschule München, Germany

Launch Date: 29 September 2021

MASS (Manufacturing of Structures in Space) is an experiment to test a rigidization method on inflatable structures for space applications. Cylindrical and conical shaped structures made of polyester film will be tested in the stratosphere on board of the high-altitude balloon BX31 by inflating the flat-folded structures and rigidize them with an integrated resin that cures once exposed to ultraviolet radiation. One of the unique developments will be the effective integration of the resin onto the constructions to rigidize the structures and prevent collapse once the pressure inside the structures decreases. The resin is supported by fibres that will form a helix structure around the inflating part. The inflatables consist among others of conical shape structures to allow an application as a helix antenna. The union of resin and fibres can be used for further development also for the International Space Station as well as in the future planned planetary bases.

MASS Student Experiment Document

BX27: LODESTAR (high aLtitude experiment On cosmic raDiation inducEd defectS in CIGS solar cells wiTh high precision meAsuRements)

Uppsala University, Sweden

Launch Date: 18 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.

Student Experiment Document v5-1

Paper: Investigations of Cosmic Ray Induced Defects in CIGS Solar Cells 

RX23 – TESOS (In-flight temperature measurement with structurally integrated fibre optic sensors)

Technische Universität München, Germany

Launch Date: 4 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.

Student Experiment Documentation v5-0

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.

REDEMPTION Conference Paper

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.

FOCUS Conference Paper

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.

GaGa Conference Paper

GaGa Paper