SONATE-2 Satellite

Spacecraft name SONATE-2
Form factor CubeSat
Units or mass 6U
Status Operational (4S 2024 paper as of May 2024)
Launched 2024-03-04
NORAD ID 59112 
Deployer EXOpod Nova 12U/16U [Exolaunch]
Launcher Falcon 9 (Transporter-10)
Entity name University of Würzburg
Institution University
Entity Academic / Education
Headquarters Germany
Launch brokerer Exolaunch

Development and operation of a technology test satellite for highly autonomous payloads and artificial intelligence.


As part of the SONATE-2 mission, novel hardware and software technologies of artificial intelligence (AI) are to be verified in miniaturized format in earth orbit. By using such AI technologies, the satellite can independently analyze the environment and start autonomous recordings. 

Deep learning plays a special role as a versatile image processing tool. In addition to the classification of targets already known at the start of the mission, the payload should also have the option of on-board training for the detection of anomalies as previously unknown objects or phenomena.

The mission objectives of the SONATE-2 satellite can be divided into three different parts:

  1. The operation of an amateur radio payload - The development and operation of the satellite is used for the education of students of our university. In cooperation with the DLR School Lab in Neustrelitz, Germany, it is planned to use the amateur radio payload for the education of high school students.
  2. The operation of a novel payload using artificial intelligence as a technology demonstration in space. The amateur payload of SONATE-2 consists of a VHF transceiver that was already built for the predecessor mission SONATE over the curse of several student theses. For SONATE-2 additional student theses extended the transceiver functionalities. It will provide regular SSTV downlinks with images from the optical sensors included in the AI payload as well as an APRS digipeater and CW beacon.

On the education side, the mission will serve as a foundation for different aspects of the university aerospace and computer science engineering program. In the context of practical courses, theses or as student assistants, students can participate in the development of all subsystems of the space and ground segment, including the amateur radio payload and the technology demonstration payload. In the context of mandatory lectures and exercises on space operations every student will also be included in the operations of the satellite.

The German Aerospace Center (DLR) offers a School Lab for high school students at the location of our external ground station in Neustrelitz, Germany. Besides experiments on space and satellites, the School Lab includes amateur radio contacts to the ISS under the supervision of licensed local radio amateurs, which they wish to extend to other satellites like in this cooperation with the SONATE-2 mission.

The AI payload is a newly designed payload using powerful, but power efficient computing hardware and multiple optical sensors is VIS and IR. It is capable of not only the execution of neural networks but also their training in orbit. Applications include autonomous classification of images on the pixel-level, object detection and anomaly detection.

Besides the amateur and educational mission parts, the SONATE-2 mission also has a research objective for the demonstration of novel artificial intelligence technology in the space environments. While the AI payload is mainly operated using a separate up/downlink in the space operation service in S-band, the satellite bus and the amateur payloads are operated in the amateur service. Housekeeping telemetry in the amateur service also contains status information of the non-amateur payload


During the first weeks of its operation in orbit during LEOP and commissioning the SONATE-2 performs as expected. All systems have been checked out and the post-launch calibration of the AI payload and satellite bus has started. The amateur radio payload was activated on several days and was successfully received by radio amateurs worldwide.

All four deployable antennas (2m and 70cm amateur radio bands) were successfully deployed 200 seconds after separation from the deployment container. Unfortunately, the automatic deployment of the deployable solar panels 60 seconds later failed. As the separation and solar panel deployment as well as the first contact occurred on the night side of Earth, the temperature of the deployment mechanism was already lower than expected. Therefore, the solar panels were successfully deployed manually by telecommand later in LEOP during a pass in the Sun. This was no problem for the LEOP operations as power budget und communications were designed to be sufficient in case the solar panel deployment would fail.

From the first successful contact 1 hour after launch SONATE-2 was operated on all passes over the ground stations in Würzburg. Except the deployment of the solar panels the satellite was in nominal state as expected. After five days, only the weekday passes between 12:00 and 16:00 UTC were used to command the satellite, while the night and weekend passes were solely for automated telemetry downlink. During the first days, all subsystems have been turned on at least once on both redundant busses to see that everything survived the launch as expected.

Active detumbling of the satellite during LEOP was not necessary. After separation the remaining rotation was around 5 deg/sec around the primary axis of the satellite (see Figure 13), slowing down by 1 deg/sec/day. The remaining rotation of less than 1 deg/sec is preferred for thermal reasons compared to a total detumbling by active control. Therefore, further detumbling is only performed when required for payload operations. 

Sources [1] [2] [3] [4] [5] [6] [7] [8]
Photo sources [1] [2] [3] [4] [5] [6] [7]
Keywords Propulsion
On the same launch

Last modified: 2024-05-29

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