Quick start

OPERA proposes a lot of options and configurations. Anyway, in order to allow starting first computations very quickly, the OPERA GUI proposes many parameters set to default values.

Launch the main GUI

To launch the GUI you only have to double click on Windows systems or type :

 java -jar opera-xx.x-jar-with-dependencies.jar

First time the GUI is launched, a specific directory (OPERA_DATA/) with its sub-directories (contex/t, outputrun/, results/, work/) will be created if it does not already exist. These directories will be used to store data/results working files. Note that the name of these directories may be changed (see this specific page on properties files).

Mandatory data

If many data are included in the jar file (solar activity, force models data, ...), no TLE data are directly provided. So the user will have to get it for example via the [Space-Track site]. By default, these TLE will be stored:

• in the tles/ subdirectory with the following organization: XXX/YY/XXXYY.tle file where XXX are the first three digits of the NoradId; YY are the last two digits of NoradId. the .tle contains history of TLE for this NoradId

• in the tlesbyday/ subdirectory with the following organization: YEAR/DAY.2l file which contains for a specific day, the last TLE for each object that has been updated during the last year and that is still in orbit.

So, in order to start easily, some files are available here.

Select Norad Ids

Based on the data given in the previous file, we can select which orbital objects to study. Different ways of selecting them are available (see specific page) but, as an example, we will use the simplest one, giving directly the Norad Ids by clicking on the Add button. We will enter the following integer numbers separated by blank characters:

By clicking on OK, the two objects are well selected and recognized as we can see it:

Computation

Now, it will be possible to start a computation by clicking on the Computre button. Unfortunately, the computation exits in error status with such a message:

TLEs was found in the requested time window. The last available date is xxxxx days too old

This error is due to the fact that, by default, the "End of history" date is the current date and is to far from the actual reentry dates of these objects. So, in order to get results, we will have to change this date, entering this one: 24/11/2011 00h00m00s

Clicking again on the Compute buton will then give these output results: