In DTM implementations with an Adobe Analytics Tool, it was common to call
_satellite.getToolsByType('sc').getS(); which would return the AppMeasurement object (often called the "s" object). This was a hack from the start, but often a necessary one.
In DTM we had "Tools". In Launch we have "Extensions".
Assuming that you want to gain access to the "s" object of Adobe Analytics from within (non-AA) custom code in Launch, your best bet will be to check the box "Make tracker globally accessible" in the Adobe Analytics Extension Configuration panel. This will expose the "s" object as
window.s which will allow you (or anyone else) to access it and its functions from anywhere.
Assuming that you have the same needs but you want to keep the object tucked away within the Launch enclosure (not exposed globally), it is possible to create a simple extension that will access the 'get-tracker' shared module exposed by the Adobe Analytics extension and return a handle to the "s" object.