Mars Express operations engineer Daniel Lakey has just sent in a quick update. Daniel wrote:

During the critical parts of the MSL EDL, Mars Express will be busy recording
MSL’s radio beacon and so will be turned away from the Earth. This means that all of the commands need to be on-board beforehand. Using the techniques developed over the last year (https://webservices.esa.int/blog/post/7/1382), a week’s worth of commands are sent to the spacecraft at a time, to execute over the week.

Commands are packaged into ‘activities’, which are unpacked into the on-board computer’s RAM just in time to execute.

When Mars Express has the final Earth contact before it slews away for EDL, the controllers at ESOC will confirm that the relevant activities are on board and executing normally.