[@SimpleWriter] Okay, the idea of the 387 outpost is that it's in the right area for long-range observations of the SR System.  It is SR-388's neighboring planet, which means there's a good chance it saw - from a distance - everything going to and from the BSL Station orbiting SR-388.  This means that it would've been there to see the BSL Station put into the orbit in the first place, deliveries, Samus' arrival, the Metroid-producing area breaking off and exploding, and then BSL Station's destruction along with anything that would have escaped, Samus and all.  The reason the Admiral wants the team to go there is that more accurate information on Samus' departure from the system can be gathered, and also where the X went, so that they can more-accurately try and figure out where to look for sources of [i]them[/i].  (The reason they don't have that already is because Adam the AI stopped delivering them intel.)

Does that help?