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SALSAT - Spectrum AnaLysis SATellite

Artistic Impression of SALSAT during an overflight in the low earth orbit
Lupe [1]

   

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)
  • 2020-09-29 Core System checkout
  • 2020-09-30 Historic Telemetry Analysis
  • 2020-09-30 Regarding our and community Doppler observations SALSAT is probably object 2020-068K (SCN 46495) but not finally confirmed yet
  • ... commissioning

The following Links can be used for further updates/information about the project and launch:

  • Updated Website: TU Homepage [2]
  • Social Media: Follow TUBSpace [3] and SALSAT [4] on Twitter!
  • Documents: Amateur Radio Informations [5]
  • Youtube Trailer: English [6] / Deutsch [7]
  • Youtube Interview: TU Interview [8]

See the TUBIX10-COM document [9] for Communication System Specifications incl. preliminary LEOP TLE. To import the TLE data directly into your orbit prediction tool you can use this source [10] hosted by DK0TU.

SALSAT Team Members in front of the S band antenna of TU Berlin's groundstation
Lupe [11]
SALSAT Team Members at the Integration Facility in September 2020
Lupe [12]

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 [13], 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 [14] 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 [15], 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 [16]) for attitude control of nanosatellites
  • Modified S-Link RF transceiver for full-duplex communication in the S band
SALSAT satellite overview
Lupe [17]

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 [18] 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 [19]). 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

SALSAT (Spectrum AnaLysis SATellite) project team
project lead
Jens Großhans, M.Sc. [20]
systems engineer
Dipl.-Ing. Huu Quan Vu [21]
software engineer
Philipp Wüstenberg, M.Sc. [22]
electronics engineer
Michael Pust, M.Sc. [23]
communications engineer
Sebastian Lange, M.Sc. [24]
student assistant
Alexander Balke, B.Eng. [25]
student assistant
Thee Vanichangkul, B.Eng. [26]
SALSAT Team 2020
Lupe [27]

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 [28]and SALSA [29]). 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 [30] project. This project also utilizes the SLink [31] RF transceiver. The secondary payload for attitude control is developed, qualified and manufactured within the FDA [32] 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.

SALSAT: Technical Paramet
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
Lupe [33]
Lupe [34]
Lupe [35]

   

Publications

TU Berlin Satellite Programmatics and Multi-Ground Station Concept
Citation key vonderoheTUBerlinSatellite2019
Author Martin von der Ohe, Sascha Weiß, Sascha Kapitola, Livio Gratton
Title of Book Proceedings of the 2nd IAA Latin American Symposium on Small Satellites
Year 2019
Address Buenos Aires, Argentina
Abstract With the launch of BEESAT-9...-13 Technische Universität Berlin (TU Berlin) has successfully launched and operated 21 satellites. Mission objectives include technology demonstration, communications experiments and education. In 2019, 12 of these satellites are still operated on a daily basis and seven more satellites are to be launched before 2022. The main communication link for TT&C is in the amateur-satellite UHF band, which comes with both advantages and disadvantages. The main advantage is that the UHF amateur equipment is comparatively cheap, easy to install and handle and can be deployed even under harsh environmental conditions. The disadvantage is that data rates are low and amateur-satellite bands require compliance with amateur rules. For payload data, S band transmissions in the space-research bands are used. While these bands provide higher data rates, the ground station setup is more complex and more difficult to set up in a remote area. Besides the technical parameters of the ground stations, operational requirements have to be taken into account. Most TU Berlin satellites are developed by different project teams, having concurrent operation needs and not always a common operations system. This necessitates thorough planning of ground station availability and mission operations. When capacity limits of single ground station solutions are reached, a ground station network for satellite operations becomes necessary. TU Berlin has pursued an approach of successively building up a distributed network of ground stations with international partners throughout the world. This paper provides an overview of TU Berlin's satellite missions and their ground station network. Besides the ``home base'' on the rooftop of the institute of aeronautics and astronautics at TU Berlin, stations in Backnang (Germany), Longyearbyen (Svalbard, Norway), Buenos Aires (Argentina) and San Martin Base (Antarctica) exist. These stations are either built and operated independently or in close collaboration with partners, e.g. Instituto Colomb of UNSAM in Buenos Aires. Additionally, transmissions that are down- linked in amateur-satellite bands are collected via the SatNOGS network. The paper will conclude with an outlook of how TU Berlin plans to further optimize the ground station network.
Download Bibtex entry [36]

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Fachgebietsleitung

Prof. Dr.-Ing. Enrico Stoll
Tel. +49 30 314-21339
Room F 515
sekretariat@rft.tu-berlin.de [38]

Grant No.:

50 YB 1805

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