REXUS 7 Teams:
MONDARO:
 MONDARO
MONDARO - Measuring of neutral-gas density in the atmosphere by rocket
The MONDARO experiment comprises three identical Pirani gauges mounted on the same ram deck of the payload. One gauge to be placed on the symmetry axis of the payload and the other twosensors has to be symmetrically mounted behind the shock front. Pirani is a sensor that utilizes thermal conductivity principle for gas density measurements. The measurements of the central gauge will yield the first successful high-resolution density measurements using a costeffective rocket-borne instrument. The measured densities of the neutral atmosphere will then be integrated assuming hydrostatic equilibrium, yielding the temperature profiles. An aerodynamical correction factors have to be applied to the density measured inside the gauges because of the shock front that arises due to the high speed of the sounding rocket. For the central sensor placed on the symmetry axis of the payload, these factors have to be calculated using the direct simulation Monte Carlo technique (DSMC). Comparison of the measurements made by the central sensor with the side-mounted ones will yield an experimental ram correction factors for suchhardware configuration. These experimental ram correction factors can further be compared with the factors calculated using the DSMC.
Team: Dörte Petzsch, Robert Püstow, Robert Matschos, Ralf Steinwehr
VIBRA-DAMP:
During the flight of every despun ballistic missile there is a period of nearly perfect weightlessness. For the REXUS sounding rocket this period is about two and a half minutes long. The only forces still acting inside the rocket during this phase are coming from disturbances in the atmosphere and moving devices inside the rocket. For experiments which are reliant upon a high microgravity quality these residual accelerations can still be too high. Our goal is to develop a passively damped experiment module for REXUS which will isolate the major part of these forces. The idea is based on an award-winning diploma thesis from a former student of the Aachen University of Applied Sciences. We will create a lightweight case which will fit into a REXUS standard module. It will be connected to the rocket structure during the zero-g period only by some small beam-springs. The contactless damping of that case is based on the eddy current principle (e.g. known from the braking system of the ICE high-speed train). A permanent magnet is located in front of a plate which is built from an electrically conductive material, without permanent magnetic attributes. When the magnets move relatively to the plate, a current is induced inside the plate. The current creates an own magnetic field which acts against the original movement. First rough calculations showed that it is possible to create a system with an eigenfrequency of under 1Hz which could isolate about 95% of the forces acting on the damped system. To verify the expected results we will insert two seismic acceleration sensor packages into the REXUS module, which will measure the acceleration within the damped system and at the surrounding structure. The position and number of springs and magnets strongly depends on the mass and mass distribution of the damped experiment. As we want to create a damping system for integration of other experiments, we have to provide software tools for spring length, thickness, number and position calculation. Another important feature is to create a locking mechanism for the case which will keep it in a fixed position during start and landing. This mechanism has to prevent movement of the case to avoid plastic deformation of the extremely tender springs and more important to circumvent the destruction of the rocket during the start because of a free flying device inside of it.
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BUGS:
BUGS - Boom for University Gravity-Gradient stabilized Satellites
BUGS is a student experiment to analyze whether satellite boom deployment is able to provide gravity gradient attitude stabilization. If the experiment succeeds, the boom will be boarded on the UNISAT-5 university satellite. It is suggested that booms could provide small satellites with nadir pointing attitude by means of simple passive stabilization, without the need for active control, permitting them to carry out a number of different experiments involving Earth observation. The proposed boom is based on an innovative low cost concept, which uses the principle of the tape coil spring; it can be deployed once and it maintains its rigidity since every coil is blocked inside the following one.
Team: Chantal Cappelletti, Fabrizio Paolillo, Jacopo Piattoni, Maria Libera Battagliere
Scuola di Ingegneria Aerospaziale, Rome, Italy
REXUS 8 Teams:
Suanieadh:
The aim of the experiment, named Suaineadh pronounced 'shin-aid') after the Gaelic word for 'twisting net', is to demonstrate both the ability to control the dynamic deployment of a web in space and the stability of the spinning web after the deployment. The payload consists of a mother section (or hub), a square net of 2x2 m and four corner masses attached to the web. Prior to the deployment, the net and corner masses will be kept folded around the hub, with an approximate volume of only 10cm3.
Team: Christie Maddock, Leo Chen, Chris Murray, Malcolm McRobb, Norilmi Ismail,Rafael Ritterbusch, Pau Mallol
University of Glasgow, United Kingdom & Kungliga Tekniska Högskolan, Stockholm, Sweden
LapLander:
LapLander - Light Airbag Protected Lander
LAPLander is a prototype design for an ejectable payload, which could be used to gather multi-point measurements of plasma characteristics in the magnetosphere. As no standard off-the-shelf recovery system exists for such a small, fast-spinning payload, LAPLander uses an inflatable structure both to decelerate the fall and as protection at the moment of impact. The system is equipped with sensors for flight diagnostics and a redundant radio system with a radio-beacon and a satellite transmitter. All the collected data will be stored in an on-board memory, and the payload will transmit the ground GPS position to facilitate the payload recovery.
Team: Joakim Sandström, Malin Gustafsson, Torbjörn Sundberg, Christian Westlund,Xin Li, Oliver Neuner, Matías Wartelski
Kungliga Tekniska Högskolan, Stockholm, Sweden
TUPEX:
The Chair of Astronautics at the Technische Universität Berlin (TU Berlin) is setting a focus on pico- and nanosatellites. Due to their cost effectiveness and variability satellites with a mass of less than 20 kg become more and more attractive for future space missions. During the last decade miniaturization of satellite bus subsystems was continuously gaining importance. The main objective of TUPEX-3 is the in-flight verification of a newly developed communication system and a sun sensor for pico- and nanosatellites. The data transfer in future pico- and nano- multi-satellite systems occurs both between the ground and space segment as well as directly between the satellites. In order to make the above mentioned communication strategy possible, a novel telemetry and telecommand system using the UHF band is currently being developed at the TU Berlin. Implementation of an inter-satellite link between multiple units rises additional challenges compared to common point-to-point connections.
The experiment is based on three or four identical radio modules, which imitate a multisatellite system. During flight one module on the REXUS rocket exchanges data with the other communication units, which are regarded as „ground based" satellites. A connection between the „satellites" will be established, data will be transferred and saved with a time stamp. In such way the suitability of the communication system will be tested to enable an in-orbit cross-link between future satellites of the TU Berlin. Sun sensors are used in astronautics to determine the attitude of a spacecraft in relation to the sun. The sensors tested here are based on a photosensitive device and are being optimized in regard to power consumption, mass and volume. A special feature of these sun sensors is that they determine the vector of the sun in the body-fixed coordinate system of the satellite independent from other hard- and software. Thus they can easily be integrated in different systems. During flight of the REXUS rocket, a data logger unit especially designed for the experiment will be storing data from several sun sensors and reference sensors for evaluation. The integration of the verified systems is planned in future small satellites developed at TU
Berlin.
Team: Walter Frese, Cem Avsar, Jens Riesselmann, Sebastian Trowitsch, Martin Herfort, Dimitri Junoschew,Falk Kempe, Johannes Lieb, Rozbeh R. Alavi
VECTOR:
The experiment "Verification of Concepts for Tracking and Orientation" (VECTOR) will be performed by a team of students from the Institute of Astronautics at Technical University München (Germany). The experiment is separated into the following two sub-projects: 1. A space based verification experiment for the evolved version of the On-Board-Data-Handling (OBDH) unit that was developed at LRT and will be flown on the Cubesat mission MOVE. The OBDH unit will be extended for coding of higher data rates, real-time video payload processing and CCSDS conform packetizing and depacketizing. In addition, the performance and link stability of two S-Band antennas will be measured and transmitted during launch and in space.
With the integrated camera a real-time observation of the separation, re-entry or another experiment is possible due to video trans mission over the S-Band link. 2. A ground based experiment for the demonstration of high precision antenna tracking. The signal from the S-Band antennas onboard the REXUS sounding rocket will be autonomously tracked by a space qualified S-Band antenna with pointing mechanism on ground to demonstrate high accuracy and autonomy for future intersatellite communication technologies. The received data will be de-multiplexed, splitted in telemetry and video and displayed in real-time by an associated data processing system.
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