BX33 – SPACIS (Sound Propagation in the Atmosphere using Complex Infrasonic Signals)

Faculdade Engenharia da Universidade do Porto

Launch Date: October 2023

The propagation of sound in the atmosphere suffers from considerable attenuation, except at the lower end of the spectrum: Infrasound waves with frequencies as low as 20 Hz can be perceived hundreds of kilometres from their source. Several studies have already been carried out to measure the atmosphere up to the stratosphere as a propagation channel. Such studies are a gateway to measuring the atmosphere’s physical properties at different altitudes and locations. Most of these studies used helium-inflated balloons. However, they are all based on receiving sporadic transmitting sources, mostly from high-intensity natural explosions (this was even the case in an earlier BEXUS experiment).

The SPACIS experiment aims to use artificially generated complex infrasound waves to perform such studies at a much higher granularity. Such signals have a long duration so that the energy is scattered in time, requiring much lower transmission power. In addition, their careful design and synchronization of transmission and reception allow the measurement of the actual propagation delay by correlation. These signals are transmitted continuously, allowing a large number of independent measurements throughout the BEXUS flight. This high granularity of measurements will allow the computation of meaningful propagation maps and models for infrasound waves in the stratosphere.

The transmitting source will be compact and based on the release of bursts of compressed air controlled by a synchronized microcontroller. They will be easy to install on the ground and operated without special consideration for harm to life and nature. Infrasound sensors with specially designed acoustic interfaces adapted to the BEXUS gondola will provide a constant flow of measurements that will be acquired, stored, and downlinked in real-time. During the flight, the team will analyse this data to assess transmission detection. Further offline processing will provide maps of wave speed, refractive index, and attenuation near the flight path.

BX32 – ROMULUS (Radio Occultation Miniaturized Unit for LEO and Upper Stratosphere)

Sapienza University of Rome

Launch Date: October 2023

The contribution of GNSS (Global Navigation Satellite System) Radio Occultation (RO) atmospheric data to Numerical Weather Prediction and climate monitoring could be enhanced by increasing the daily RO profiles over the regions of interest together with lowering the costs. To investigate this topic, ROMULUS will perform GNSS Radio Occultation from a stratospheric balloon, testing a miniaturized unit based on a Software Defined Receiver (SDR) and commercial off-the-shelf components. By performing RO measurements, ROMULUS could demonstrate an optimal complementary solution to the standard technique operated from Low Earth Orbit (LEO) satellites and ground receivers. In fact, a small-scale GNSS RO unit could be integrated in the already existing infrastructure of weather sounding balloons, increasing the temporal density of local RO profiles with a low-cost configuration. Moreover, this solution could be adapted to the LEO environment, leading to the achievement of GNSS RO operated from constellations of nanosatellites. During the BEXUS flight, ROMULUS will receive the occulting GNSS signals with SDRs. GNSS observables will be sent to the ground station as input for an analysis software to obtain profiles of refractivity, density, pressure, and temperature, from an altitude of about 4 km up to the maximum altitude of the balloon. The accuracy of profiles will be then verified through atmospheric reanalysis models. Moreover, the use of SDR enables the storage of all the received raw RF samples, which can be later re-processed in post-flight activities with different signal tracking algorithms. In addition to the widely used GPS signals in L1 and L2 bands, ROMULUS will also process signals from Galileo and GPS signals in L5 band. This will enable the experiment to compare L5 RO tracking performances with L2 carrier. Indeed, the new L5 band has interesting features of increased power, enhanced cross-correlation protection, and more precise pseudo-range estimation.

BX31– SARIA (Synthetic-Aperture Radar using an Inflatable Antenna)

University of Porto, Portugal

Launch Date: 29th September 2021

Synthetic-Aperture Radar (SAR) is a form of radar that uses the motion of the antenna over a target region to provide an image with fine spatial resolution.

The goal of our experiment, SARIA (Synthetic-Aperture Radar using an Inflatable Antenna), is to perform SAR of the ground surrounding the flight path, from the BEXUS gondola, with a COTS Software Defined Radio (SDR) and a reflector inflatable antenna that is designed and built by us.

Inflatable antennas have several possible applications, as they are very lightweight and portable. Their usage may help reduce the size needed for small imaging satellites. The stability of the BEXUS flight in the stratosphere and the size of the antenna upon inflation allows the performance of low-power SAR using the license-free C-band ISM band, while complying with all laws and regulations.

With this experiment, we hope to test the feasibility of this kind of technology. We expect to create several images of the ground with sufficient resolution to distinguish rivers, lakes, houses and forests from the rest of the terrain.

SARIA Student Experiment Document

RX28 – ROACH-2 (Robotic in-orbit analysis of cover hulls 2)

University of Stuttgart, Germany

Launch Date: 7 November 2022

The REXUS experiment ROACH2 (Robotic in-Orbit Analysis of Cover Hulls 2) of the Small Satellite Student Society at the University of Stuttgart (KSat e.V.) is supposed to evaluate the feasibility of a rover moving on a spacecraft in reduced gravity and vacuum. To do so, the rover should move inside a REXUS rocket on an obstacle course using electrostatic adhesion to adhere to it. During ascent of the rocket, the rover will be held in place by a Rover Holding Mechanism and will be released by it immediately after the despin of the rocket. The experiment will be monitored by several sensors such as distance sensors to detect whether the rover is still in contact with the hull of the rocket, rotational encoders that measure the movement of the rover and a set of cameras to record footage of the experiment for real-time verification and post-flight analysis. The unique characteristic of this experiment is that thus far no such system for remotely controlled maintenance of hulls of spacecraft has successfully been demonstrated.

RX27 – BLACKBOX II (Locatable crash safety data storage device for sounding rockets)

University of Applied Science Bremen, Germany

Launch Date: Experiment did not fly

The BlackBox2 is the follow-up mission of the BlackBox experiment that flew on RX24. The BlackBox2 project was re-initiated parallel to the City University of applied Sciences Bremens STERN-Project, AQUASONIC II. On the first STERN mission (AQUASONIC I) the telemetry link intermitted shortly after launch. A system failure during flight caused the rocket to disintegrate.

Since hardly any component survived the impact, no conclusive data for the cause of the failure could be recovered. Sounding Rocket Experiments have a lot of critical components that can lead to failure of a mission. Even though detailed procedures and extensive testing are used to reduce the risk in a mission, especially experimental rockets can fail in a lot of different ways and it’s not always easy to find the source of the failure by analyzing available telemetry data or video footage of the mission.

In the aviation industry, flight recorders have been around for a while to recover data after system failure or even crashes to help investigation. The goal of the BlackBox2 is to develop a device similar to those used on planes, but for sounding rockets.

A rocket grade flight recorder has to be more compact and withstand higher forces during launch and impact than a flight recorder used in aviation. It also needs to be highly reliable when writing data. The BlackBox (BB) experiment that flew on REXUS 24 has proven the feasibility of such a device. The BlackBox2 (BB2) experiment will improve on data rates, storage capacity and provide a standardized interface so that it could be re-used in future missions.

BX27 – QUEST (Quadspectral Unaided Experiment Scanner of Topography)

Julius-Maximilians-Universität Würzburg, Germany

Launch Date: 18 October 2018

QUEST is the acronym for Quad-spectral Unaided Experimental Scanner of Topography. It scans the planet surface by analysing an array of four light sensors (RGB and IR) and a spectrometer. As a result, the experiment should produce an overview image of the surface with marked areas depending on the type of it. The experiment should distinguish between snow, water, plants, rocks and overlaying clouds. Areas which can’t be recognised should be marked specially.

The designated target is to build an autonomous system which could be used in interplanetary missions with demanding constrains on the bandwidth. Therefore, we must develop a reusable algorithm that could be adjusted with different parameters for varying planet surfaces. Regarding to the hardware the experiment has to be built in a modular way so that we can easily swap sensors for missions with distinct requirements.

Besides of the experiment an infrastructure hast to be built to analyse and command the experiment.

RX26 – TRACZ (Testing Robotic Applications for Catching in Zero-g)

Wrocław University of Science and Technology, Poland

Launch Date: 19 March 2019

Grasping objects by non-human in space conditions is in many cases neither effective nor convenient. Lack of general-purpose device which can grab differently shaped and sized elements made from various materials is one of many issues in space missions. Classical approach towards gripping objects by human-like rigid effector requires sophisticated trajectory planning algorithms, numerous sensors and complicated mechanical design. Another approach is to use soft, elastic materials manipulated with pressure to adjust to an irregular-shaped object and catch it. Soft grippers are less complicated in construction and use, furthermore they seem to be more all-embracing. In many industries (for instance light bulbs and glass products) soft grippers are in common use due to theirs high adaptability. One type of those grippers is based on the jamming of the granular material.

TRACZ (Testing Robotic Applications for Catching in Zero-g) is an experiment which aims to investigate the possibility of application of such device in space, where negative differential pressure is impossible to obtain and lack of gravitation may cause the granular substance inside the gripper to behave in an unpredictable manner. During REXUS flight, in microgravity and vacuum conditions series of catches will be performed on an single object and the force with which the object is held will be measured. The results will be compared with an on-ground experiment and the utility of the aforementioned gripper in the space applications will be discussed.

RX25 – HEDGEHOG (High quality Experiment Dedicated to microGravity Exploration, Heat flow and Oscillation measurement from Gdansk)

Gdańsk University of Technology, Poland

Launch Date: 11 March 2019

As access to space conditions becomes more available, both technically and economically, scientists interest in launching finer and more sophisticated experiments grows. To be qualified for launch, such experiments need to be carefully tested prior to the event. The tests should represent actual launch conditions as closely and in as detailed manner as possible. For this reason, comprehensive measurements of launch conditions are required.

This experiment focuses on measuring acceleration and vibrations (especially eigenfrequencies) conditions and heat transfer inside a sounding rocket as a reference for future ground acceptance tests. It features patented device for heat flux measurement and set of cantilever beams for vibration amplification.

RX25 – FLOMESS (Flight Loading Measurement System)

Universität der Bundeswehr München, Germany

Launch Date: 11 March 2019

The FLOMESS (Flight Loading Measurement System) experiment is intended to measure the structural strains during the flight of a sounding rocket. The occurring structural loads will be calculated from the conversion of the measured raw data. Furthermore the system shall measure the effects of thermal stress to isolate them from the measurement. This is necessary to determine the pure structural strains. An accurate knowledge of the loading during flight will aid to enhance the existing calculation programs. Also an efficient design of rockets will be achieved by reducing the semi empirical safety margins for the structure.

RX24 – AQUASONIC  II – Black Box (Development of a memory flash device)

University of applied Science Bremen (Hochschule Bremen), Germany

Launch Date: March 2018

The BlackBox experiment is intended to test a redundant and independent data storage system in sounding rocket missions. The system is to be investigated with regard to the effects occurring during rocket launch, the prevailing ambient conditions as well as the results due to a crash. The influences include a very high acceleration as well as low temperatures. In addition, the system shall have a reliable localization system with which a recovery of the data memory can be ensured.

RX24 –  PIOneERS (Measuring Plasma Impedance Of ne using Ejectable Recoverable System)

University of Birmingham, United-Kingdom

Launch Date: March 2018

The ionosphere is an ionised region of the Earth’s atmosphere, which can have a significant impact on several types of radio systems, such as satellite navigation systems and satellite communications. Measurements of the electron density in the ionosphere can be used to improve models, thereby enabling the development of better techniques to mitigate the impact of the ionosphere on radio systems. Hence, an impedance probe, ImP, is being developed to provide in-situ electron density measurements.

The PIOneERS experiment is a technology demonstration experiment designed to validate the performance of two space systems, ImP and a boom. The data provided by ImP in the bottom-side ionosphere will be compared to already available data to determine its performance. Once the ImP data will be validated, it will be used to provide in-situ electron density measurements in the top-side ionosphere. As the measurements provided by ImP are highly susceptible to magnetic fields, the sensor will be mounted at the end of a boom of 1.75 m in length, away from the artificial magnetic field caused by the REXUS rocket body. Data provided by an inertial measurement unit at the end of the boom will enable to validate its performance (deployment speed, oscillatory behaviour and structural stability) during and after deployment in a micro-gravity environment.

This text flight will increase the technological readiness level and act as a precursor to future orbital flights for both systems.

RX24 – ROACH (Robotic in-Orbit Analysis of Cover Hulls)

University of Stuttgart, Germany

Launch Date: March 2018

The REXUS experiment ROACH (Robotic in-Orbit Analysis of Cover Hulls) of the Small Satellite Society at the University of Stuttgart (KSat e.V.) is going to evaluate the feasibility of a rover to analyse the outer hull of spacecraft for damage as well as its deployment system. Therefore, the suitability of an elevator needs to be determined, which will carry the rover from the inside of the REXUS rocket module to the outer skin of the rocket. Furthermore, the experiment will investigate the applicability of electrostatic adhesion as a method for the rover to adhere to and move on the hull. The elevator is to be extended at the beginning of the microgravity phase. Once its platform aligns with the rocket’s skin, the rover drives out and moves on the outside of the rocket for a short distance. During this phase, a beacon on the rover transmits data to a ground station. This is done in order to track the rover in operation and in the emergency case of a separation, which will be triggered if it does not return to the elevator correctly. Furthermore, the experiment will be monitored by several sensors such as distance sensors to detect whether the rover is still in contact with the hull of the rocket, a number of sensors that measure the movement of the rover and a set of cameras to record some actual footage of the experiment for real-time verification and post-flight analysis. The unique characteristic of this experiment is a novelty as by now no such system for remotely controlled maintenance of hulls of spacecraft exists.

RX23 – MORE (Measuring Optoelectronics in Rocket Experiment)

ISAE-SUPAERO and University Paul Sabatier of Toulouse,  France

Launch Date: March 2018

The development and maturation of optoelectronic devices for terrestrial telecommunication that occurred during the past decades has opened new opportunities for space telecommunication. Since 2013 the NIMPH project “Nanosatellite to Investigate Photonics Hardware” (ISAE-SUPAERO, University Paul Sabatier and LAAS-CNRS consortium) seeks to quantify the robustness of a classical optoelectronic telecommunication transmission chain when subjected to the hostile conditions of outer space radiation. The actual NIMPH payload architecture, designed by University Paul Sabatier and LAAS-CNRS, contains optoelectronic components that might represent a risk to the complete architecture reliability (e.g. optical switches). The MORE project offers an interesting opportunity to experimentally prove the reliability of a part of NIMPH. The MORE payload aims to measure the behavior of a short optical fibered transmission during launch and a complete flight timeline. Regarding the results, it is expected that the properties and structural integrity of the optoelectronic devices (laser, photodiode, opto-mechanical switch) including the optical fibers taken during flight will match those obtained in the laboratory. A dedicated optoelectronic payload for the MORE project is designed by students of University Paul Sabatier and packaged in LAAS-CNRS. Furthermore, the proper functionality and reliability of the fabricated OBC (On Board Computer) designed from ISAE-SUPAERO in both hardware and software will be validated, as well as anomalies detection that could potentially affect the development of the NIMPH mission. Currently, this fabricated board is still in its experimental stage and not fully tested under space environment conditions in a laboratory. In conclusion, the behavior in space environment, that MORE will collect, will provide us a valuable experimental understanding of OBC, optoelectronics component and optical fibers robustness during a short flight at 80 km altitude.

RX24 – WOLF (Wobbling Control system for spinning Free falling unit)

Royal Institute of Technology (KTH), Sweden

Launch Date: March 2018

The reason behind the start of WOLF project is an experiment called SPIDER (Small Payloads for Investigation of Disturbances in Electrojet by Rockets), which was developed under the Swedish national balloon and rocket programme. SPIDER carried a payload of ten (10) Free Flying Units (FFU) which were released from the main payload at ~65 km. The FFU’s deployed probes on wire booms to measure turbulences in the auroral electrojet between 95 km and 115 km. Unfortunately, those FFUs experienced a wobble motion (i.e. rotation around the two axes perpendicular to the spinning axis), probably induced when the FFUs were ejected from the rocket. Due to this wobble motion, the wire booms occasionally came in contact with the FFU’s structure which created short-circuits and corrupted a significant portion of the measurement. While the short-circuiting as such is easy to mitigate, the irregular motion of the probes compromises the measurements as the position of the probes cannot be assumed radial. The WOLF mission statement is achieving a flat spin on two (2) disc-shaped FFUs. Hence, our main technical objective is designing, building and validating an in-flight wobbling control system to reduce the lateral rates of the FFUs. Once validated during RX24 flight, the wobbling control system will be used to improve any future experiments which require a flat spin of the FFUs.

RX21 – DREAM (DRilling Experiment for Asteroid Mining)

Wrocław University of Technology, Poland

Launch Date: 15 March 2017

In present days space operations are not only measured in scientific and technical goals. Economical aims are recently gaining bigger influence in spaceflight exploration. One of the greatest opportunities is asteroid mining. Although there is certainly a big gap between current spaceflight operations and running space mining industry, scientists and engineers already work hard on simulating asteroid conditions for excavating ore such as platinum or nickel.

The experiment’s scientific goal is to measure the conditions and aspects of space excavating, especially to measure the output distribution and condition of output after excavation. Part of these parameters will be measured by the sensing equipment in Measurement Chamber with vision system during flight and the rest will be the result of on-ground analysis.

The most challenging part of designing space equipment is to ensure that it will survive both harsh conditions of delivery and work in the outer space. The technical goal of the experiment is to design the robust equipment able to perform drilling operations in space.

BX23 –  PREDATOR (PREssure Difference dependency on Altitude verificaTOR)

Czech Technical University, Czech Republic

Launch Date: 7 October 2016

The goal of this project is to evaluate precision of differential altitude measurement which is intended to solve problems related to low-cost inertial measurement systems in airplanes. The system measures pressure at five locations and due to the known distance between sensors the actual attitude of the object can be determined. Our aim is to come out with a new source of information which can be used in the present Attitude Heading and Reference Systems for sensor errors (span and drift) correction. Data from the real environment provided by the balloon shall be used to evaluate noise and jamming of the output through the whole span of the measurement range which can be achieved through BEXUS experiment.

RX19 – SLED (System of Free Falling Univts using LEDs to allow one to track the other)

KTH Stockholm, Sweden

Launch Date: 17 March 2016

SLED – System of free-falling units using LEDs to allow one to track the other – will eject two free-falling units (FFUs) from a sounding rocket in flight. The aim of the project is to enable one of these FFUs to track the other without a link. Such a system is interesting because tracking without cooperation can be useful within many other scientific and technical applications. Moreover, these FFUs should then measure the carbon dioxide density in the surrounding atmosphere. Such measurements are of interest due to the effect of carbon dioxide on climate change and the difficulty of measurements at such altitudes.

To accomplish these goals, the design has three major components: two free-falling units housed within one rocket-mounted unit (RMU). The FFUs are distinct and can be identified as the Transmitting Unit (Tx) and Receiving Unit (Rx). Both FFUs are ejected simultaneously from the RMU during the sounding rocket flight. At this point they act autonomously and conduct the experiment. Each is equipped with its own recovery system, which is deployed automatically at a prescribed altitude, allowing the units to land safely and transmit their respective locations.

BX21 – SPADE (Smartphone Platform for Acquisition of Data Experiment)

Universidad de Sevilla, Spain

Launch Date: 7 October 2015

SPADE aims to test a low-cost real time data acquisition platform for stratospheric exploration missions based on commercial off-the-shelf hardware. It will be composed of one or more smartphones and an auxiliary sensor network. The sensor network is composed of sensor nodes, like those being used currently on industrial applications, connected among them by a low powered standard wireless connection (protocol 802.15).

The experiment is a technology demonstration which includes two main goals: firstly, to study the behavior of the wireless network, also integrating communications to and from the ground station, in a demanding situation such as those conditions that will be aboard BEXUS (stratospheric environment: low pressure + low temperature) above all, in such conditions that cannot be reproduced in ground (irradiation) and secondly, we want to test the performance of sensors, commercial batteries and smartphones as the central unit for this type of platform in this harsh environment.

RX17 – SCRAP (SCattering of Radar waves on Aerosols in Plasmas)

KTH Stockholm, Sweden

Launch Date: 17 March 2015

The scientific objective of SCRAP is the validation of the theories on electron density fluctuations in dusty plasmas by measuring the scattering of ultra-high frequency radio waves on a cloud of metallic microparticles spread in the mesospheric plasma. These theories are often used as a basis to reconstruct the characteristics of mesospheric aerosols (mainly particle size, charge and number density) from indirect measurements, such as electron and ion density fluctuations obtained from radar and optical observations or mass spectrometry. These indirect methods are unavoidable, since the actual collection and preservation of mesospheric particles is subject to the technical difficulty to perform experiments in the mesosphere and a high risk of contamination. By using the ground-based incoherent scatter radar system EISCAT to observe a cloud of calibrated mesospheric dust particles, the SCRAP experiment proposes to relate theoretical predictions to a controlled object. The results would also provide a new insight on phenomena such as polar mesospheric summer echoes, anomalous radar echoes which are thought to be caused by mesospheric clouds of ice particles.The success of SCRAP strongly relies on the technical possibility to spread a controlled uniform cloud of monodisperse metallic particles above an altitude of 80 km. Hence, the design of an adapted injection system, allowing a precise tuning of the cloud’s characteristics, is an integral part of the experiment.

RX15 – FOVS (Fibre-Optice Vibration Sensing Experiment)

Technical University of Munich, Germany

Launch Date: 29 May 2014

As an in-flight experiment in the REXUS 15 programme, the “Fiber-Optic Vibration Sensing Experiment” (FOVS) aims at the application of so-called fiber Bragg grating sensors. Fiber Bragg gratings are optical gratings inscribed to the core of an optical fiber. They allow for entirely optical measurements of temperatures, mechanical strain and of deduced quantities, such as vibration. Due to their properties { mechanical robustness, high dynamic range etc. Fiber Bragg gratings are particularly suited to cope with the harsh environmental conditions in a rocket vehicle (very high and very low temperatures, intense vibrations, presence of flammable propellants, etc.).

The FOVS experiment aims for a demonstration of a fiber-optic vibration measurement system in an actual flight, to evaluate its benefits compared to conventional electrical sensing in the challenging launcher environment.

Such a vibration measurement system can contribute to emerging technologies in the commercial launcher segment. Particularly, entire fields of measurement data can be acquired with minor mass contribution. This can be applied to techniques such as structural health monitoring, active vibration damping, and actuator monitoring, enabling lighter structures without compromising on reliability.

RX15 – ISAAC (Infrared Spectroscopy to Analyse the middle Atmosphere Composition)

KTH Royal Institute of Technology, Sweden

Launch Date: 29 May 2014

The main objective of ISAAC is to develop, build and demonstrate a system with two Free-Falling Units (FFUs), where, after being ejected from a sounding rocket, one FFUis able to optically track the other, i.e. to keep the other FFU within a narrow field of view. The secondary objective is to determine the CO2 concentration in the middle atmosphere by means of IR spectroscopy. The FFUs will both be spin-stabilised, since they are ejected from a spinning rocket. The first FFU (ISAAC-Tx) is entirely passive in the tracking process. It will be equipped with separate light sources for both tracking (visible spectrum) and spectroscopy (IR). The other FFU ( ISAAC-Rx) has a tracking camera to and the light emitted from ISAAC-Tx and the sensors required for the spectroscopy. It has a non-spinning part which will be pointed towards ISAAC-Tx with a two-degree-of-freedom control. Once ejected from the rocket, the experiment is completely autonomous. It is equipped with a parachute, a GPS system, a satellite modem and a radio beacon, allowing it to land softly and transmit its location, thus making a recovery possible. Post-flight analysis will allow to reconstruct the trajectory of the FFUs, assess the tracking performance and evaluate the results from the spectroscopy.

RX13 – SOLAR (SOLdering Alloys in Reduced Gravity)

Lulea University of Technology, Sweden

Launch Date: 9 May 2013

Millions of dollars are spent on maintaining the International Space Station (ISS) due to components in need of replacement. Imagine reducing the cost of this maintenance by repairing equipment on-site. The current method of soldering joints in micro-gravity generates defective components, (thus) making the repairs insufficient in outer space.

The main problem is to solder metals in reduced gravity without obtaining an increase of void fractions, which are inherent due to the lack of buoyant forces on flux and gases. Earlier tests conducted by NASA, in reduced gravity alone, show an increased amount of void fraction by up to three times the normal earth gravity. Soldering in vacuum, or in a gas flow, in addition to reduced gravity, enables us to minimise void fractions. In vacuum or a gas flow we can simulate an actual repairing sequence done at the ISS. The result of the reduced gravity soldering will be analysed and compared to the similar studies done in the SoRGE- and CLEAR projects by NASA, and by our own samples (made without vacuum). Suggestions on how to obtain the needed environment will be given based on the final test results.

SOLAR Conference Paper


RX13 – CERESS (Compatible and Extendable REXUS Experiment Support buS)

Technical University of Munich, Germany

Launch Date: 9 May 2013

An analysis of REXUS projects at the Institute for Astronautics at TU Munich has shown that an entire infrastructure had to be especially designed and built for every experiment. The requirements and tasks of these infrastructures were normally very similar though, always including a regulated power supply, on-board data handling, autonomous control of the experiment and real-time data transfer to and from the rocket. Besides these basic functions many teams wished to have a real-time visualization of the flight. The main goal of the “CERESS” project is the development of a standard platform providing the most important functionalities, allowing future teams at TUM to concentrate more on their scientific focus. Once verified on the first flight, all sensors can be directly applied to future experiments. After recovery of the experiment all collected data can also be analyzed on the computer. In addition to acceleration, temperature and pressure sensors, a camera will document the progression of the experiment. Monitoring and control software on the ground will enable a thorough surveillance of the rocket module’s situation throughout the entire flight. Remote control of the experiment as well as sensor- or time-based actions will be possible. A visualization tool will illustrate the rocket’s trajectory (and attitude) in a 3D simulation live and post flight. This complements the “CERESS” project with a widely requested feature that allows the general public to access the fascination of REXUS experiments.

RX14 – PoleCATS (Polar test of the Conceptual And Tiny Spectrometer)

University College London, United Kingdom

Launch Date: 7 May 2013

The aim of the PoleCATS experiment is to demonstrate in the lower ionosphere an exciting new concept in space plasma instrumentation. The proposed concept will use CATS – the Conceptual And Tiny Spectrometer – which is a novel, highly miniaturised plasma analyser head, together with an unconventional detector for low energy electrons, a CCD (charged-couple device). CATS offers the unique ability to study simultaneously multiple energies of electrons and ions using extremely compact electrostatic optics, allowing for very rapid sampling of plasma energy distributions. Specially processed CCD detectors offer a sensor that can potentially detect both electrons and ions without the high voltage and high vacuum requirements of conventional low energy plasma instruments. It is hoped that these components can be used to analyse the fluxes and energies of ionospheric electrons throughout the REXUS flight. Instrumentation based on this combination of CATS and CCD provides an attractive low-resource solution for a range of space plasma applications. It has the potential to drastically improve upon the current generation of space plasma instruments for use in the scientific study of the Earth’s magnetosphere and beyond. The highly miniaturised design would also allow them to be flown on nano-sats such as CubeSats. It is envisaged that this technology will be further developed for this application.

PoleCATS Conference Paper

RX11 – GGES (Gravity Gradient Earth Sensor)

EPFL, Lausanne, Switzerland

Launch Date: 16 November 2012

The aim of the GGES experiment is to test the effectiveness of a Gravity Gradient Torque (GGT) attitude determination and control system, by measuring the rotation of an elongated silicon proof mass under free-fall conditions. The principle is based on the use of a MEMS (Micro Electro Mechanical System) device that can measure the gravity gradient vector, which always points to the centre of the Earth. GGT has been used to stabilise small satellite after launch, but never as an attitude determination scheme. Instead of the current Earth sensing methods that determine the Earth vector by measuring the Earth’s IR emission, GGES will investigate a much lighter and more compact MEMS-based solution, and from the collected data determine to what accuracy it can be used for attitude measurement for Low Earth Orbit (LEO) satellites. The MEMS approach does not require optical access, and thus one single, compact unit located anywhere inside the satellite provides full 4p steradian field of view. The REXUS flight will approximate the conditions of a launch to LEO, i.e. acceleration followed by a period of free-fall (ballistic trajectory after motor burn-out), during which data will be gathered from the Earth Sensor. The residual rocket rotation will also help to test the design, since G was designed keeping in mind that a satellite can also spin after separation from the launcher. It is primarily designed to measure displacement due to GGT only in free-fall.

GGES Conference Paper


BX15 – MISSUS (Meteorological Integrated Sensor Suite for Stratospgeric analysis)

University of Padova, Italy

Launch Date: 25 September 2012

Stratospheric balloon missions are playing an increasingly important role in the international scientific community, due to the fact that they can operate in near-space conditions, with a significant reduction in costs, timelines and mission requirements. MISSUS was conceived as an innovative, integrated multi-sensor scientific package, dedicated to the characterisation of the most significant environmental parameters of thin atmospheres; such as temperature, pressure, wind velocity, humidity etc. as well as balloon attitude and trajectory reconstruction. The primary goal of the MISSUS project is to collect meteorological and attitude data, in order to validate the atmospheric models during the ascent, float and descent phases of the mission. A synergic methodology known as ‘data fusion’ will be used for the data analysis. A BEXUS flight provides a unique opportunity for testing the innovative on-board instrumentation, which will be designed using knowledge gained from previous CISAS missions, such as HASI and SoRa. In addition to this, the characterisation of the meteorological sensors’ properties will provide a reference for future interplanetary applications; such as the instruments to be used for ExoMars mission.

MISSUS Conference Paper

RX12 – SOMID (SOlid-borne sound Measurement for Independent event Detection)

University of Munich, Germany

Launch Date:  19 March 2012

The SOMID experiment will aim to detect any self-imposed or induced events occurring within the REXUS system by measuring the resultant micro-vibrations. Every kind of mechanical event on a space vehicle induces micro-vibrations into its structure, which can be analysed to yield data concerning the event in question. This will be done by installing accelerometers on the supporting structure and the outer hull, which will measure generated specific and well-defined events. Those events will be created by two valves and a servomechanism which are fixed to the structure. The piezo-based accelerometers will be operating during the entire mission so that data can be collected from the valves and the servomechanism as well as every other kind of vibration caused during the different mission phases. The measured data will be stored on a data flash storage for post flight evaluation. Laboratory experiments have proven that every event has its specific frequency spectrum. This spectrum can be used as a method of error analysis during flights or for future experiments as a possible way of detecting the impact of micro-meteorites in space based applications.

RX10 – M-BEAM (Magnetic BEAring for brushless DC Motors in microgravity)

Higher Technical College of Electronics, Moessingerstrasse, Austria

Launch Date: 23 February 2011

The M-BEAM experiment demonstrated a wear and maintenance-free brushless DC motor for spaceflight applications. In the past, operational wear and tear on dynamic systems such as motors and reaction wheels has often resulted in the diminished capacity or even mission failure of spacecraft. A high profile example of this was the failure of the Hubble Space Telescope’s reaction wheel stabilisation system, which resulted in a very expensive Space Shuttle service/repair mission. The M-BEAM experiment consisted of a magnetic bearing stabilised rotor system, which utilised both passive and active elements. Such a system allows contactless interaction between a motor’s stator and rotor thereby eliminating any friction between the working components. During the microgravity phase of the flight the experiments physical characteristics were measured; including local and ambient temperature of the system, the stability of the rotor via displacement sensor readings and the critical rotation speeds by observing the resonance behaviour of the system. It was hoped that the technology displayed in this study could be adapted for future use in a reaction wheel system.

M-BEAM Conference Paper

BX10 – I-BATE (ISU-Balloon-borne ATC Technology Experiment)

International Space University, Strasbourg, France

Launch Date: 9 October/23 November 2010

The goal of the I-BATE experiment was to track aircraft from the 30 km vantage point offered by the BEXUS balloon, by receiving and storing the Automatic Dependant Surveillance-Broadcast (ADS-B) transmissions sent by passing aircraft. In Europe alone, approximately 30,000 commercial aircraft take flight every day. In controlled airspace, these flights are managed by an array of more than 75 air traffic control radar centres throughout Europe, to maintain orderly air traffic patterns and prevent collisions. In uncontrolled airspace, such as the Polar Regions and transoceanic routes, no such air traffic control system is in place. In these regions the pilot of each flight is responsible for their own collision avoidance, and there is no means of tracking lost aircraft. To mitigate this discrepancy, the ADS-B system has been developed, which allows aircraft to transmit their flight number, GPS position, airspeed and intentions so that all aircraft and ground stations within range can track each other. The I-BATE experiment had a line-of-site range of nearly 1000km for aircraft flying at a 10km altitude and aimed to prove this concept by receiving the ADS-B transmissions of all suitably equipped aircraft in range of the receiver. Each data point was stored in an on-board memory and recovered with the balloon payload. As a secondary goal, a subset of received data was transferred to the ground and incorporated, real-time into aircraft tracking software.

I-BATE Conference Paper

BX09 – SO-hIgh (Silicon On Insulator)

Université Catholique de Louvain-la-neuve, Belgium

Launch Date: 11 October 2009

The aim of the SO-hIgh experiment was to assess the applicability of Micro-Electro-Mechanical Systems (MEMS) technology in space and stratospheric research, by way of a meteorological board and positioning system. Multiple MEMS sensors were used for this experiment to measure atmospheric parameters; such as humidity, temperature and UV levels. Several of these MEMS sensors were manufactured by the SO-hIgh team using layered Silicon-insulator-silicon substrate, known as SOI, which displays remarkable resistance to radiation and extreme temperature gradients. Accelerometers, gyroscopes and pressure sensors were also used to determine the experiments attitude and position during flight. These MEMS-SOI systems are of particular interest to space applications due to their low cost and incredibly small size, mass and power consumption. However, they have yet to be extensively tested in near-space conditions. The SO-hIgh experiment therefore sought to flight-test these systems in order to determine their physical limits, and verify the quality of their measurements.

RX05 – Itikka (Inertial measurement unit)

Technical University of Tampere, Finland

Launch Date: 13 March 2009

The Itikka team has an ongoing research programme, known as Supikoira, which focuses on the development of a hybrid sounding rocket, containing electronics payloads. One of these payload components is an Inertial Measurement Unit (IMU), which serves as the active guidance and stabilisation system for the rocket. The purpose of this experiment was to design, develop and test an improved, next generation IMU2 utilising MEMS technology and an in-built flight computer. The objective of the experiment was achieved by flying the IMU2 in aCRE real operational environment, namely the REXUS rocket, and by analysing and comparing the collected data against the corresponding flight data of REXUS. The Itikka experiment also featured high altitude digital photography for student outreach purposes.