We are currently working on communications protocols for radio telemetry.

We are drafting a specification for what we call a Nearspace Protocol (NSP) stack. The NSP is optimized for low footprint, can survive random link loss and can be used on different communication link types (slow radiomodem links, non-realtime messaging networks etc).

Primarily the NSP stack specifies a transport protocol that is used to transfer mission critical information such as geographic positions, commands and system status. The transport protocol also supports encapsulating different content layer protocols which will be used for transferring instrument data (for example images) during mission flight. The Transport Layer Protocol (TLP) specification is mostly complete, but encapsulated Content Layer Protocols (CLPs) are still work in progress.

The first CLP we have a preliminary specification for is the Content Transfer Protocol (CTP) which is essentially a robust, low footprint file transfer protocol that can survive on low-quality communication links.

We have also realized that there is a need for transferring extended diagnostics information and have begun working on second CLP; the Diagnostics Event Protocol (DEP). DEP will be used to sending and requesting extended sub-system status information during mission flights. It will supplement but not replace the mission-critical (but limited) system status information transferred inside Transport Layer Protocol (TLP) packets.