Mission Analysis (MA)

The MA domain in a CDF study will mostly use COMET to view other domain’s values and model manoeuvres, orbits, etc. The following steps use the example of a Manoeuvre to be modelled in the Tutorial COMET model:

  1. Connect to Citrix and open the COMET Application. To do so, follow the steps outlined here.

  2. Connect to the CDF COMET server and open the model Tutorial COMET. To do so, follow the steps outlined here.

  3. Also open the model MA catalogue. To do so, follow the steps outlined here.

  4. Open the Element Defintion browser for both the Study Model and the Catalogue Model. You can do that by following the steps outlined here.

  5. Use the Generic Manouvre from the catalogue to define the Manoeuvre Element Definition in the Tutorial COMET model. To do so, follow the steps outlined here.

  6. Use the Reference Data Library to add the additional parameter propellant type to the Element Definition. To do so, follow the steps outlined here.

  7. Populate the Manual fields of the Parameter Values for the parameters manouvre type, time, delta_v and the newly created propellant type parameter. To do so, follow the steps outlined here.

  8. Create 1 Element Usages of the Manoeuvre in the Space Segment Element Definition. To do so, follow the steps outlined here.

  9. The tutorial model contains 2 Options: the “Default” Option describing the baseline spacecraft design and the “Expanded” Option describing a larger version of the spacecraft with a larger payload. This requires some changes in the MA design:

    1. The Manoeuvre in the “Expanded Option” should have a different delta_v and therefore this parameter needs to be Option dependent. To do so, follow the steps outlined here.
    2. Introduce different values for the delta_v parameter in the two Options.
    3. The “Expanded Option” will also require a 2nd Manoeuvre inside the Space Segment which is not necessary in the “Default” Option. To do so, follow the steps outlined here.

Example Equipment - MA

In the above steps the COMET Application was used to directly interact with the Study Model. However, one of the key advantages of storing data on the COMET server is that it also offers the possibility to interact with the Study Model using standard Excel workbooks and using the COMET server as an interface between the workbooks of the different domains. In the following steps, an overview on how this link between the Study Model and Excel can be achieved with the Excel COMET Plugin is provided. A specific Excel workbook for the MA domain has been set-up by the MA experts from previous CDF studies and should be available in the Study Folder of the CDF Working drive (accessible from Citrix). In this tutorial, for the sake of simplicity, a blank Excel workbook will be used to demonstrate the basic functionality:

  1. Use the COMET Application to subscribe to the parameter wet mass of the Spacecraft Element Definition. To do so, follow the steps outlined here. This parameter will be needed for the Excel computations.

  2. Connect to Citrix and open an instance of Excel with the COMET Excel Plugin. To do so, follow the steps outlined here.

  3. In Excel use the COMET Excel Plugin to connect to the CDF COMET server and open the model Tutorial COMET. To do so, follow the steps outlined here.

  4. Execute a Rebuild and find the wet mass parameter Actual Value cell in the Parameters sheet. To do so, follow the steps outlined here.

  5. On a new sheet in the Excel workbook perform a simplified calculation to compute a value for the delta_v parameter of the Manoeuvre making use of the cell name referring to the Subscription of the wet mass parameter. To do so, follow the steps outlined here.

  6. Attribute a cell name to the result field including the calculated delta_v parameter. To do so, follow the steps outlined here.

  7. In the Parameters sheet insert the cell name as a formula in the Computed field of the delta_v parameter and set the Switch accordingly. To do so, follow the steps outlined here.

  8. Use Submit to “push” the computed value to the Study Model. To do so, follow the steps outlined here.

  9. Switch back to the COMET Application and verify the new value is introduced in the delta_v parameter and marked as ready for publication (highlighted in blue).