Test - Integrate - Control

MTL management & more

New features have been added to support a full flexible onboard queue management
Many missions use onboard command scheduling to manage the fact that spacecraft often do not have continuous radio contact. For some time, TSC has supported sending and verifying such delayed nested commands using the ECSS PUS service 11. The implementation duplicates that of SCOS2000.

Nevertheless, mission time line management (with telecommand verification) can be problematic for ground systems in different missions because the MTL implementation quite often differs in subtle ways from one mission to another.

When the ground system sends a service 11 telecommand containing an execution time and a nested telecommand that should be executed in the future onboard, it also sets up an expectation of when that TC will execute, and sets up the TC verification accordingly. The ground system maintains a “model” of what the onboard system has loaded onboard.

However there are other commands that may: reset the onboard schedule, enable or disable onboard commands, reschedule the time that they should execute, etc. Ideally we would like the ground system to modify its “model” of the onboard schedule accordingly.

Unfortunately it is extremely difficult to do this in a generic way because the list and format of MTL manipulation commands is different between so many missions.

Therefore we have added support for
  • manipulating the MTL model directly from TOPE scripts (e.g. delete, list by properties)
  • subscribing to TC as they are sent

This makes it possible to write completely flexible TOPE scripts to monitor the commands that are sent (e.g. type 11 commands) and update the ground MTL model accordingly. Of course demonstrations of such a script are available in the SelfTest test pack.