The description of the concept how to plan SCIAMACHY operations in SODAP adresses

1.) planning concept
2.) measurement planning
3.) SCIAMACHY external requirements
4.) Instrument configurations

1.) Planning concept

In the first part of the Commissioning Phase, the Switch-On and Data Acquisition Phase (SODAP), SCIAMACHY executes the functional and performance checkout and performs initial calibration & monitoring measurements. The interleaving of these types of activities is caused by the requirements to investigate the detector signals under different hardware and thermal configurations. The selected approach allows to generate a database of calibration & monitoring results from the very beginning of the mission onwards. For SCIAMACHY SODAP ends with the implementation of the final flight states at about L+120 days. This is much longer than SODAP for most of the other instruments onboard ENVISAT. However, all these instrument have their calibration measurements planned after the SODAP part of the Commissioning Phase.

The overall planning concept is sketched below.

SODAP operations planning concept

This is the driving planning document for SODAP. It assigns activity windows with a granularity of orbits to instruments and spacecraft. Within these windows an instrument may either be operated mission planning driven or procedure driven. For SCIAMACHY mission planning driven operations invoke the MEASUREMENT TIMELINE mode, i.e. the generation of measurement data. Procedure driven activities are those where pre-defined Flight Operation Procedures are executed by operators at the FOCC to achieve a particular instrument task.

In SODAP rules do exist which reduce the degrees of freedom for assigning instrument activities to orbit windows. These include e.g.

The ENVISAT System SODAP plan is maintained by ENVISAT.

The SCOOP provides SCIAMACHY's planning down to the level of procedures. It is primarily engineering oriented. The details of the engineering activity in the SCOOP allow the operators at the FOCC to prepare the sequence of procedures. For time intervals where SCIAMACHY runs in MEASUREMENT mode the SCOOP does not list individual timelines but leave this to the SCOMP (see below).

The SCOOP is controlled by Astrium-SCIA in close cooperation with ENVISAT SODAP and SOST. Particularly the orbits whit merged procedure and MPS driven activities require careful harmonization.

A number of monitoring engineering activities is not SODAP specific but must be executed for the whole mission, starting close after switch-on of the instrument. These are

The background tasks are not explicitly mentioned in the SCOOP but invoked by procedures on defined timescales. Upon analysis of the monitoring results, it may be required to interrupt the nominal SODAP plan and implement corrective activities (e.g. decontamination). All engineering background activities are developed under the responsibility of Astrium-SCIA.

The SCOOP equivalent plan for SCIAMACHY's MPS driven operations in SODAP is the SCOMP. It lists on orbit level the individual timelines to be executed in order to achieve certain commissioning objectives. Additionally, the configurations, which run sequentially during SODAP, can be derived from the SCOMP. No engineering activities are included. SCOMP and SCOOP together provide a complete view of what is planned for SCIAMACHY in SODAP.

In case of re-planning, the SCOMP must be re-adjusted. This may require close cooperation both with the SCOOP and the ENVISAT System SODAP plan. As with the SCOOP, the SCOMP is maintained by Astrium-SCIA.

Information related to planned events in the SCOOP/SCOMP and the history of the actually executed operations can be found on the dedicated web page provided and maintained by Astrium-SCIA.

2.) Measurement planning

Of prime interest for the science and engineering groups involved in the analysis of measurement data from SCIAMACHY SODAP is the concept of Measurement Planning. This is a subset of the aforementioned planning concept. The concept follows a top-down approach consisting of 3 major steps. These are

The entity listed in brackets are responsible for the particular step.

Top-down approach for SCIAMACHY SODAP
measurement planning

3.) SCIAMACHY external requirements

The figure above displays a large number of SCIAMACHY external planning requirements (blue shaded boxes). These have to be considered in all three steps of the planning activities.

The various groups involved in the Commissioning Phase (SODAP) defined the measurement goals = objectives for the first months of in-orbit operations. From the large number of proposed objectives two reviews selected those with the highest priority. The accepted objectives formed the basis for the next planning step, i.e. the definition and implementation of SODAP specific states and timelines. As the objectives required the instrument to be in certain hardware configurations, the sequence of cover openings and SRC door release was the result of trade-off considerations on objective level.

The external requirements to be fulfilled are

The SCOMP reflects the actual status of these requirements. However, the planning front-end at SOST has to deal with additional requirements, which can only be implemented in the SCOMP in an iterative process between Astrium-SCIA and SOST.

In the preparation of the operational planning input to ENVISAT during SODAP, SOST has to consider

In SODAP these requirements shall be known about 1-2 weeks prior to operations, at the latest.

4.) Instrument configurations

During SODAP, SCIAMACHY's status is characterized by CTI Configurations. Each of these define a specific

With the start of mission planning driven operations, SCIAMACHY executes subsequent configurations. However the resulting configuration sequence is not consecutive as monitoring configurations are invoked several times after critical activities.

Whenever the configuration ID changes it is required to upload new sets of measurement parameter tables. As long as the configuration remains stable, the measurement parameter tables remain stable as well. Only in the case of the Basic Scan Profile table modifications occur within a configuration due to the limited number of basic scan profiles.

The configurations can be directly translated into SODAP Timeline Sets. All timeline sets have been defined such that there is minimum timeline exchange necessary during SODAP.

Page generated 25 February 2002; last update: 19 March 2002