Less than one month after the initial release of µD3TN, we had the opportunity to run a field-test on board ESA’s OPS-SAT satellite during an overflight on 11 December 2020. As part of the test, we successfully transferred Bundles between the ground and space segment. A µD3TN instance in our infrastructure exchanged Bundles via the Internet with a µD3TN instance running on the OPS-SAT. The OPS-SAT link was provided by ESOC via an SSH connection and used µD3TN’s TCPSPP convergence layer adapter.

Apart from being the first known in-flight-test of the Bundle Protocol Version 7 draft specification, it was also the first duplex communication with the OPS-SAT via the Internet.

The test is another milestone for providing a production-ready DTN protocol implementation – and, additionally, it was quite some fun!