Communications

Launching space missions at sea requires a large infrastructure of telecommunication systems. Copenhagen Suborbitals uses both COTS equipment and in-house developed radio systems that together provide efficient support for the missions.

The figure below shows an overview of the radio systems that are currently in use or are planned to be used in the near future.

copsub_telecom_bandplan

The figure shows an overview of the radio systems that are currently in use or are planned to be used in the near future.

 

The above chart includes both the mission specific systems (telemetry, telecommand, etc), as well as the more common communication and radio navigation systems, such as radar and GPS. The following sections give a brief overview of the mission specific systems and references for further reading.

Telemetry downlink
Data collected onboard the launch vehicle and the space capsule is recorded and transmitted to mission control for real-time monitoring and post flight analysis.

The telemetry downlink system has been developed during the Sapphire mission. It uses GFSK modulation in the 2.4 GHz band and can provide up to 2 Mbps data rate including forward error correction. The system has been designed to have fast lock time and to cope with the dynamical conditions expected on experimental rockets

The telemetry downlink system has been developed during the Sapphire mission.
It uses GFSK modulation in the 2.4 GHz band and can provide up to 2 Mbps
data rate including forward error correction. The system has been designed to
have fast lock time and to cope with the dynamical conditions expected on
experimental rockets

 

 

The telemetry downlink system is an open source design. Hardware design files, firmware and software source code is available through a Github project.

Telecommand uplink
While all onboard functions are performed autonomously, various mission critical functions like separation and abort have a manual backup provided through a hot-redundant command uplink channel.

The telecommand uplink will utilize the 432 MHz band. It is currently being developed within the scope of the HEAT 2X mission.

Video downlink
The launch vehicle and space capsule is equipped with high definition video cameras. The video is recorded and transmitted in real-time to mission control from where it is included in the public Internet stream.

The video downlink system is built based on the DVB-S2 or DVB-T standards (to be decided) and uses the 1.2 GHz amateur radio band.

Voice up- and downlink
Manned space missions require voice contact between the astronauts and mission control. For this purpose, a digital voice link will be developed either using a dedicated radio link or as part of one if the existing radio links.

Mission WLAN
The mission WLAN is a wireless network between the various locations participating in mission operations. Currently this includes the launch platform Sputnik, the mission control vessel Vostok and the Internet gateway located on the island of Bornholm. The mission WLAN uses the 5.7 GHz band and has as of writing been tested to provide 50 Mbps data rate at 35 km range.

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The microwave disc mounted atop a tall grain silo just outside Nexø provides us with up to 50Mbs bandwith to the mission control ship. The WIFI link is used for video, voice and telemetry between mission control and our facility in Copenhagen.

 

Automatic packet reporting system
In addition to AIS the automatic packet reporting system (APRS) is used to report the location of the maritime vessels participating in mission operations. The position reports appear in real-time at the http://aprs.fi/ site under the callsigns OZ9VST-12 and OZ9SPT-12.

The APRS trackers are based on the KissOZ design provided by OZ7HVO and OZ1EKD.

Locator beacons
Future launch vehicles and space capsules might be equipped with dedicated locator beacons supporting the post-flight recovery operations.