SNET OPS

As part of a grant from the DLR space agency to the Technical University of Berlin (TU Berlin), in-orbit technology verification has been carried out with four nanosatellites called S-NET (S-band network for cooperative nanosatellites, link to project site) since February 2018.

The S-band transceiver SLink (IQ spacecom) was successfully tested and verified in orbit and the link budget for ISL (intersatellite link) connections was confirmed. An ISL connection could be established at over 300km. Even after more than four years in orbit, the satellites continue to operate. The relative distance to each other is controlled by adjusting different atmospheric friction (differential drag). The current relative distance of the satellites can be seen in the following figure. The low distance drift over time opens new options in the long-term analysis of the experiments.

S-NET OPS thus builds on the successful implementation of the S-NET mission and extends satellite operation for long-term analyses. The main work includes mission operation and mission planning, the scientific evaluation of the telemetry and status data from the payloads and the subsystems and the upgrading of the ground station. The satellites will be used to demonstrate applications such as connectivity of agricultural vehicles. In agriculture, high increases in efficiency can be achieved by networking sensors, devices and vehicles. LEO satellites can provide connectivity in the most remote areas.

At the TU Berlin, the following members of the team are employed on the project:

• Zizung Yoon, Project Manager

• Walter Frese, Systems engineer 

• SNET OPS was supported by German Aerospace Center (DLR) Space Agency (Raumfahrtmanagement) with funds from the German Federal Ministry of Economic Affairs and Technology (BMWT), Grant No: 50 YB 2002

Peer Reviewed Journals

Zizung Yoon, Walter Frese, and Enrico Stoll. “In-Orbit Performance of the Narrowband Intersatellite Mission S-NET”. In: 2022 IEEE Space Hardware and Radio Conference (SHaRC) (2022), pp. 1–4. DOI: 10.1109/SHaRC53093.2022.9720032.

Zizung Yoon, Yeerang Lim, Sebastian Grau, Walter Frese, and Manuel A. Garcia. “Orbit deployment and drag control strategy for formation flight while minimizing collision probability and drift”. In: CEAS Space Journal 12 (2020), pp. 397–410. ISSN: 1868-2502. DOI: 10.1007/s12567-020-00308-6.

In Proceedings

Walter Frese, Udo Renner, Klaus Briess, and Zizung Yoon. “Design and On-Orbit Experience of Reaction Wheels for Small Satellites”. In: 33rd AIAA/USU Small satellites. 2019.

Walter Frese, Zizung Yoon, and Klaus Briess. “S-Net first year in orbit: verification of a nanosatellite network in s band”. In: 12th IAA Symposium on small satellites for Earth observation. Ed. By Sandau. Vol. 12. 2019.

Walter Frese, Zizung Yoon, Huu Quan Vu, and Klaus Briess. “TUBiX-10 -Design and Flight Experience of a Nanosatellite Bus for Distributed Missions”. In: 70th International Astronautical Congress. 2019.