RAXEM is an advanced software tool for continuous support to data uplinking
activities for MARS EXPRESS. The aim of the RAXEM project is to propose a
flexible and easily configurable system which allows several tuning mechanisms
targeted at improving quality parameters for an uplink plan. In addition, the
design of the system is object-oriented and is implemented in Java, in order
to easily run the system under different operative systems as UNIX, LINUX,
Windows or Mac OSX
The Problem: MEX-UP
The management of the upload of the MDAFs to the spacecraft has been performed manually by the MEX Flight Control Team so far. The process is time-consuming and error-prone. The number of TCs that can be transferred at any one time, the available uplink windows and a priority scheme have to be taken into account in a transfer plan. The loss of a ground station may lead to having to reschedule the uplink plan.
A software tool is envisaged to automate the uplink scheduling and replanning of MDAFs, referred to as MEXUP, which is specify in this document.
The spacecraft activities for each month are determined in accordance with the Medium Term Plan (MTP) for the concerned period (typically 4 weeks). Based on the frozen MTP various operations requests (OR) are generated (e.g. the output of the MEXAR tool provides the data dump operations request). During the daily planning activities the operations requests are converted into MTL Detailed Agenda Files (MDAF) by the Mission Planning System. While ORs detail the operations at command sequence (CSEQ) level, the MDAF expands the CSEQ into time-tagged telecommands (TC) which are transferred to the spacecraft. On-board the spacecraft the TC reside in the Master Timeline (MTL) buffer ordered by execution time. At the specified execution time, each TC will be released and removed from the MTL.
MDAFs are usually generated at least 3 to 4 days before the planned operations. They can contain operations for up to 1 week. They typically contain between 100 and 600 TCs. All TCs should be on-board with enough time margin before execution time to allow for contingencies, e.g. the loss of uplink windows, control system problems. It is the duty of the Spacecraft Operations Coordinator (SOC) to verify coherency and completeness and coordinate the transfer of the MDAFs to the spacecraft. The MEXUP tool will support these activities.
Here is a first snapshop of the current preliminary version of RAXEM