how to approach/investigate aliens?

[joeclark77 (OP)]

I've made my first alien contacts. . . .  now how can I learn more about them?
In one case, my geology survey ship made 18 contacts and was promptly destroyed by meson fire.   I presume these were planetary defenses, so I know they live at a particular planet or its moons (helpfully the survey ship had already surveyed every other planet in that system, so that narrows it down).   The alien race shows up in my Intelligence screen but with no real info.

In another case, a geology survey ship in another system made contact with a nuclear missile traveling ~28,000 km/s five seconds before it was destroyed.   That alien doesn't appear in my Intelligence info so I know nothing about them except that they have nuclear missiles and that they might be found near a particular planet.

So,  how can I learn more about them?  Without getting vaporized, I mean?
Should I build some kind of scout ship with lots of sensors to try and get a look at their settlements?  A military to try and overwhelm them?  Or build a base in their system and wait for them to come to me?  Do something with diplomacy?  (I don't have 5 officers with diplomacy bonuses yet. )  Espionage?

[Hawkeye]

Case 1:
Let your linguists start working on their language (Initiate Communication on the CTRL-F5 window)
Send a cheap scout and pray it gathers more intel before being blown to smithereens
You can also try to drop an espionage team onto their planet.
Destroying their ships and rescueing their life pods also can give you more intel
Destroying their ships and salvaging the wrecks will give you some intel on what those ships mounted (beware tho, as those ships might not have been their state-of-the-art ones).

Case 2:
If no new race shows up, there are two possiblities:
1. It is a race you already know, i.e. the race from case 1
2. Your ship was not destroyed by an alien race at all but run into some leftover mines.

P.S.
You got 18 contacts in case 1, why do you assume those mesons that killed your ship were planet-based? I wouldn´t be so sure about that - I won´t say any more.

Have fun working out what is going on