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SALSAT - Spectrum AnaLysis SATellite
- Artistic Impression of SALSAT during an overflight in the low earth orbit
- © TUB
Launch & LEOP Information
Current schedule:
- 2020-09-28 11:20:32 UTC Launch at Plesetsk Cosmodrome
- 2020-09-28 14:46:12 UTC Separation
- 2020-09-28 23:11:37 UTC First contact (callsign DP0WER)
The following Links can be used for further updates/information about the project and launch:
- Updated Website: TU Homepage
- Social Media: Follow TUBSpace and SALSAT on Twitter!
- Documents: Amateur Radio Informations
- Youtube Trailer: English / Deutsch
- Youtube Interview: TU Interview
- SALSAT Team Members in front of the S band antenna of TU Berlin's groundstation
- © TUB
- SALSAT Team Members at the Integration Facility in September 2020
- © TUB
The Mission
The research project SALSAT (Spectrum AnaLysis SATellite) develops, launches and operates a nanosatellite with a payload for in-orbit spectrum analysis. The primary payload is the spectrum-analyzer SALSA, which has been developed and space-qualified within the recent research activities of the chair of space technology. SALSAT is based on the TUBiX10 satellite bus which has been developed at the Technische Universität (TU) Berlin. An existing flight spare satellite of the S-Net mission is utilized and modified to accommodate the specific needs of the SALSAT mission. The primary focus of the project consists of the design of Hard- and Software components as well as the operation of SALSAT in orbit. Scientific data for the analysis of the global spectrum use is gathered and processed throughout the mission lifetime. The data is used to generate heatmaps of the global spectrum use as well as to detect harmful interference. Study groups of the ITU for spectrum analysis for small satellites are also accompanied in the scope of the SALSAT mission.
The payloads
The SALSAT mission consists of the primary payload SALSA, which is a spectrum analyzer for the analysis of the spectrum utilization from the low earth orbit. SALSA solely analyzes the portion of the spectrum which is utilized for satellite communication (e.g. amateur radio bands). The following frequency bands will be analayzed:
- VHF: 145.80 – 174.00 MHz
- UHF: 400.15 – 420.00 MHz
435.00 – 438.00 MHz - S band: 2 075.00 – 2 095.00 MHz
2 255.00 – 2 275.00 MHz
The spectrum utilization will be collected and analyzed within these frequencies. As a result a global heatmap of the spectrum utilization over time and location will be generated.
The SALSAT mission will also feature multiple secondary payloads:
- Laser-Retroreflectors for ground-based high accuracy orbit determination
- Optical paylaoad for verification of the attitude control system of SALSAT
- Novel Fluiddynamic Actuator (FDA) for attitude control of nanosatellites
- Modified S-Link RF transceiver for full-duplex communication in the S band
Amateur Radio
SALSAT is a Spectrum AnaLysis SATellite. The main objective is an analysis of the actual used (amateur & scientific) spectrum to obtain a better understanding of the current challenges of frequency coordination. The Amateur spectrum data will be made available to the interested public. Space research payload data will be requested and downlinked in space research service bands. SALSAT does not include any commercial mission and does not use amateur bands for non-amateur services.
Detailed Information on how-to contact SALSAT (e.g. telemetry formats) can be found on the amateur radio website of the chair.
The spectrum data in the amateur radio bands collected over the course of the mission will be published in a online database (s/t the MarconISStadatabase). Detailed information will be published during the operational phase of SALSAT in 2021.
The reason for not using amateur-satellite bands in S band is that the transceiver has a proprietary
protocol that is not published by the manufacturer (IQWireless). Most of the spectrum data will be downlinked via this COM system. The S band transceiver has both uplink and downlink functionalities and is therefore independent from the UHF COM system.
Within several hands-on classes and projects TU Berlin uses Amateur UHF to teach satellite operations and communication technology. Currently these courses are:
- Amateur Radio Novice and Advanced Class
- Spaceflight Planning and Operations,
- Project Satellite Operations,
- Project Amateur Radio,
- Project Satellite Communications
Through these courses, we so far helped ~40 radio amateurs to obtain their license.
Nominal TT&C of the satellite and amateur payloads will be conducted in amateur-satellite bands.
The SALSAT Team
| project lead | Jens Großhans, M.Sc. |
|---|---|
| systems engineer | Dipl.-Ing. Huu Quan Vu |
| software engineer | Philipp Wüstenberg, M.Sc. |
| electronics engineer | Michael Pust, M.Sc. |
| communications engineer | Sebastian Lange, M.Sc. |
| student assistant | Alexander Balke, B.Eng. |
| student assistant | Thee Vanichangkul, B.Eng. |
Preparatory research projects
As previously mentioned the SALSAT project conducts in-orbit spectrum analysis in defined RF bands. The chair of space technology at the TU Berlin conducted preparatory work within the scope of two completed research projects (REPIN and SALSA). These projects established the theoretical and practical foundation for the SALSAT mission. The utilized satellite bus (TUBiX10) has been developed and space qualified within the S-Net project. This project also utilizes the SLink RF transceiver. The secondary payload for attitude control is developed, qualified and manufactured within the FDA project.
Technical Parameter
This paragraph contains the main technical parameters of SALSAT. It shall be mentioned that the exact parameter evolve during the development process. The table below represents the technical specifications at the stage of the Flight Readiness Review (FRR) in July 2020.
| Parameter | Value |
|---|---|
| Orbit | 575 km (SSO) |
| Launch Date | September 28th 2020 |
| Design Lifetime | >1 year |
| Mass | ~ 11.00 kg |
| Volume | 240 x 240 x 240 mm³ |
| Communication | UHF (TM/TC), S band (UL/DL of payload data) |
| Attitude Control | 3-axis control with MEMS sensors, magnetorquers and reaction wheels |
| Payload | Spectrumanalyzer (SALSA), optical camera, 3-axis Fluid-Dynamic Actuation system (FDA), Linux based processing system (IPU), S-band transceiver (SLINK) and Laser reflectors |
Publications
| Citation key | Binder.2017.IAA.ADCS |
|---|---|
| Author | Binder, Matthias and Yoon, Zizung and Briess, Klaus |
| Title of Book | 11th IAA Symposium on Small Satellites for Earth Observation |
| Year | 2017 |
| Location | Berlin |
| Journal | 11th IAA Symposium on Small Satellites for Earth Observation |
| Abstract | Due to the ongoing miniaturization within spaceborn technology, more complex payloads demanding for precise attitude information will be used on small, especially nanosatellite and picosatellite platforms. Since payload miniaturization is mainly driven by overall mission cost reduction, the corresponding satellite bus development must be a basic part of this design philosophy. Using low cost COTS sensor technology for space application can be risky due to quality and environmental specification issues, but controllable by testing and redundancy usage. COTS- and especially MEMS- sensor technology enables engineers to develop accurate and highly available low cost attitude determination systems for small satellite applications. By accommodating these low-cost sensors into arrays, broad synergy effects can be achieved: sensor availability and accuracy will be improved, whereas hardware cost still can be kept low. Another benefit is scalability. The sensor count can be easily adopted to different mission needs. This involves instant in-mission scaling as well as mission-to-mission scaling. This sensor concept will be demonstrated and verified on the nanosatellites of the S-NET mission. S-NET is a constellation of four nanosatellites demonstrating S-band inter-satellite communication and will verify communication protocols capable of handling a variety of network topologies. The attitude determination of S-NET nanosatellites is based on two magnetometer arrays, two sun sensor arrays and two gyroscope arrays. Each sensor array is processed by a dedicated array driver that will expose all obtained sensor measurements as one single sensor to the subsequent attitude determination processes aboard the satellite. Software algorithms were implemented to overcome different scenarios of sensor array failures and measurement distortion. These algorithms provide an additional virtual redundancy to the attitude determination of the S-NET satellites. All satellites are equipped with a unique pattern of retro reflectors for high precision laser ranging this will help to verify attitude determination calculated by onboard algorithms. In this paper an overview of the sensor array based attitude determination of the S-NET satellites is presented. The redundancy concept and the according software redundancy management is explained. Focus is given to the sensor fusion paths derived by combination of sensor arrays and software implemented virtual redundancy mentioned above. |
