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:
-
Connect to Citrix and open the COMET Application. To do so, follow the steps outlined here.
-
Connect to the CDF COMET server and open the model
Tutorial COMET
. To do so, follow the steps outlined here. -
Also open the model
MA catalogue
. To do so, follow the steps outlined here. -
Open the Element Definition browser for both the Study Model and the Catalogue Model. You can do that by following the steps outlined here.
-
Use the
Generic Manouvre
from the catalogue to define theManoeuvre
Element Definition in theTutorial COMET
model. To do so, follow the steps outlined here. -
Use the Reference Data Library to add the additional parameter
propellant type
to the Element Definition. To do so, follow the steps outlined here. -
Populate the
Manual
fields of the Parameter Values for the parametersmanouvre type
,time
,delta_v
and the newly createdpropellant type
parameter. To do so, follow the steps outlined here. -
Create 1 Element Usages of the
Manoeuvre
in theSpace Segment
Element Definition. To do so, follow the steps outlined here. -
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:
- The
Manoeuvre
in the “Expanded Option” should have a differentdelta_v
and therefore this parameter needs to be Option dependent. To do so, follow the steps outlined here. - Introduce different values for the
delta_v
parameter in the two Options. - The “Expanded Option” will also require a 2nd
Manoeuvre
inside theSpace Segment
which is not necessary in the “Default” Option. To do so, follow the steps outlined here.
- The
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:
-
Use the COMET Application to subscribe to the parameter
wet mass
of theSpacecraft
Element Definition. To do so, follow the steps outlined here. This parameter will be needed for the Excel computations. -
Connect to Citrix and open an instance of Excel with the COMET Excel Plugin. To do so, follow the steps outlined here.
-
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. -
Execute a
Rebuild
and find thewet mass
parameterActual Value
cell in the Parameters sheet. To do so, follow the steps outlined here. -
On a new sheet in the Excel workbook perform a simplified calculation to compute a value for the
delta_v
parameter of theManoeuvre
making use of the cell name referring to the Subscription of thewet mass
parameter. To do so, follow the steps outlined here. -
Attribute a cell name to the result field including the calculated
delta_v
parameter. To do so, follow the steps outlined here. -
In the Parameters sheet insert the cell name as a formula in the
Computed
field of thedelta_v
parameter and set theSwitch
accordingly. To do so, follow the steps outlined here. -
Use
Submit
to “push” the computed value to the Study Model. To do so, follow the steps outlined here. -
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).