- 2019.05.09: More results on IAA SSEO .
- 2019.02.01: One year in orbit. All satellites in best state! Relative distances great!
- 2018.10.02: Flight results on IAC Bremen .
- S-Band down- and uplink successful.
- Info for radio amateur: Mike Rupprecht 
- 2018.02.22: Intersatellite communication successful.
- 2018.02.19: SLink has been activated. S-band downlink is next step.
- 2018.02.07: TLEs: 43186, 43187, 43188, 43189. Relative distance stable.
- 2018.02.01: Ground contact w. all four S-NET was established.
- 2018.02.01: Successful launch of four S-NET satellites with Soyuz/Fregat.
The objective of the S-Net mission is to investigate and demonstrate the inter-satellite communication technology within a distributed an autonomously operating nanosatellite network. As space born systems have become an essential element in facing global challenges such as climate change, disaster management and maritime systems monitoring, rapid response and low cost systems are in high demand.
A key technology to increase the operational efficiency of distributed satellite systems via formations or even autonomous swarms is the miniaturizing of intersatellite communication technology. In cooperation with IQ wireless GmbH, TU Berlin developed an S-band transceiver (SLink)  with 100 kbps crosslink and 1 Mbps downlink capability suitable for accommodation in nanosatellites.
|Mission Objectives||S-band inter
satellite communication with nanosatellites|
|Satellite number||4 (Norad ID:
Height||580 km SSO|
|Launch Date||2018.02.01 02:07
|Mass||8.72 kg |
|Volume||240 x 240 x 240
|Communication||UHF (TM/TC), S-band
Control||3-axis control w. MEMS sensors, magnetorquers and
(SLINK) for ISL and up/downlink Laser reflector for high precision
Short docu about mission TV1:
The mission (image video):
Encapsulation of Fregat upper stage at cosmodrome Vostochny:
Report (successful launch and first contact):
|Author||Binder, Matthias and Yoon, Zizung and Briess, Klaus|
|Title of Book||11th IAA Symposium on Small Satellites for Earth Observation|
|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.|
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