Association for Space Research
News: Satellit-Pegasus: Langmuir-Probes active, Science Unit in Phase 3
STG-A is a nonprofit association dedicated to scientific research, development and construction of technologies for the realization of space activities and atmospheric research. In the actual projects our main goal is the development of communication systems for satellites in the space sector as well as in the ground sector. The members bring a lot of experience in the field of data transmission under difficult conditions as well as the programming of embedded systems. In the focus is also the scientific training of our members concerning new technologies for space applications. STG-A was founded specifically for the Austrian CubeSat PEGASUS, which was part of the European project QB50. For PEGASUS, which is already in orbit we developed the complete communication in space and on ground, including data handling and Mission Control Center. Our next project CLIMB is in construction phase yet.
At the moment STG-A operates a ground station in Langenlebarn, Lower Austria, which was equipped for 70cm, the communication frequency of Pegasus. In addition, Harald Fauland operates a ground station in Mäder, Vorarlberg, for 2m and 70cm. Another ground station was in WR. Neustadt, Lower Austria, also built for 2m and 70cm.
All three ground stations are combined in a ground station network via an protected data line at the Space Data Center in Vienna, where all received data are summarized, stored and evaluated. The clients of the Mission Control Center can access the data via the Internet. If commands or data have to be sent to the satellite, the Space Data Center will choose the ground station that will have the closest contact with the satellite.
The ground stations know at all times where the satellite is and when the next communication window will occur. The system works fully automatically for data reception. For legal reasons, sending always happens manually by an licensed radio amateur. For other satellite frequencies, the ground stations can be extended at any time. With the ground station network and the Space Data Center, therefore, there is a very good reception option for satellites in Austria.
Lower Austria, Antenna System 70cm, 2 X-Quad
Antenna System 70cm and 2m, X-Quad, Polarization switchable
omnidirectional ground station
The satellite PEGASUS, the Austrian contribution to the QB50 project (www.QB50.eu) is the founding project of STG. For Pegasus, STG developed and implemented the satellite's communications unit, including a peak-current buffering system, ground stations, a ground station network and the mission control center.
The self-developed Space Data Server not only allows the storage of data from the entire ground station network, but also their further processing, interpretation and presentation. The coordination of the programming of the on-board computer as well as parts of the programming itself were also carried out by the STG-A.
For Pegasus the common communication unit was completely redesigned and a redundant system unique to this satellite size was created, STACIE. Thus this small satellite is able to work with a highly efficient and fail-safe system like in large satellites. The challenge in the development was the small space and the little available energy. Therefore, TESSA, a system for storing peak currents, had to be built, also.
On 23.06.17 at 05: 59h the Indian PSLV Launcher 38 lifted off from India. On board was the first Austrian satellite, which was treated under the Austrian Space Act. A short time later, the satellite was deployed. At 09: 06h, the first telemetry was received and successfully decoded from the STG ground station in Langenlebarn, Lower Austria. PEGASUS is still in operation.
The Austrian satellite CLIMB is in construction phase. The feature of CLIMB is the FEEP (Field-Emission Electric Propulsion) thruster, which enables the satellite to “climb” from the initial orbit up to an elliptical orbit with an apogee of about 1500km. There, in the inner Van-Allen belt, measurements will be performed.
For CLIMB, STG-A develops, besides the existing communication module STACIE, a transceiver and antennas for the S-band, because higher data rates are needed. At these altitudes, the radiation is very high, thus the special difficulty for developing satellite subsystems is the radiation hardness of the components and the must of use of radiation shielding. The ground segment transceivers and antennas have also been updated to the S-band
STACIE-∆ (Space Telemetry And Command Interface) is a TT&C communication interface for small satellites in the 70cm amateur radio band. This interface provides two redundant transceivers with corresponding controllers on one board. STACIE-∆ can be powered by two independent power supplies (for each transceiver-controller). Both transceiver-controllers can be operated independently in the same or different frequencies, with the same or different RX or TX frequencies. Frequency-hopping is also possible as diversity RX. The frequencies can be changed remotely from the ground station. A data and control connection between the two TRX controllers decides every time the best RX or TX possibilities. In case of a malfunction of one channel, the other channel takes over the operation and acts as a single TT&C. A special connector is provided as a control interface for the deployment of the ISIS AntS antenna. The deployment of the antenna is possible without the any control of the OBC (On Board Computer).
Flight Heritage: PEGASUS
If the satellite is orbiting from the shadow side to the sunny side of the orbit and the solar cells get light, the accumulators are too cold for immediately charging. First they have to warm up by a small furnace. At this time the solar cells deliver too less energy for transmitting data at an acceptable level of power. Thus the power board TESSA (Top Energy Storage for Space Applications) for short energy storage was built, which is working independently of the ruling temperature.
Flight Heritage: PEGASUS
Boards for proto typing and testing with the same geometry and system bus connectors as the original subsystem boards. One type with 2 side SPB (Side Panel Bus) and one type with 4 side SPB are available.
1st Space Tech Talk 21. 11. 2019
studied Technical Physics at the Vienna University of Technology and now works as a measurement technician and IT manager at the Faculty of Physics of the University of Vienna. Since 2008 he is a licensed CEPT 1 amateur radio operator with experience in range communication under difficult conditions in the stratosphere. In 2011, he was a colleague and lecturer in the Physics Space Science Department of the ISU (International Space University). At the Austrian Space Forum he was project leader of the Stratospheric Balloon Project. In the Austrian satellite project PEGASUS he is team leader with specialization in hardware development and communication. In the course of this project he is a founding member of STG.
studied Communication Technology and Consumer Electronics at the Technikum Wien. For 16 years he has been working for Motorola with a focus on GSM and Tetra-Radio networks. As a member of the Stratosphere Balloon Team of the Austrian Space Forum, he developed STACIE as the communication unit and flight computer of the Sherpa project. He is a licensed CEPT 1 radio amateur and works as a system architect for the project PEGASUS
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