Its mostly a grind you can try get it earlier but i started during the Amphibian Stage. What you want to use are the Auto Crafters with Drones and obviously the Trading platforms. The Auto crafters are set on Pulsar Crystal as they yield 25 tokens and are relatively easy to mass produce using Drones and Ore extractors.
I suggest you set up at least 3 "T3 ore extractors" in each of a Uranium, Iridium, Osmium and Zeolite mine
Coordinates for the mines i used

• Uranium:1785:25:1945
  
  
• Iridium: 819:30:1038
  
  
• Osmium: 386:86:1161
  
  
• Zeolite: 351:115:1417
  
  You also want 3/4 T2 gas extractors set on Methane.
  
  Set your drone station up, i ended up using around 30 drone but you can use as many as you want.
  
  Once your collectors are setup, set your Trade Platform up. I made 4 of them to speed things up, you can make as many as you want.
  
  Set the Trade Platforms to automatically launch once full.
  Set all the Trade platforms to demand Pulsar Crystals using the cog and set all your extractors to supply there respected resources.
  
  Have your drones take the resources to storages set up around your Auto Crafters and then have Drones take the crafted Pulsar Crystals to the spaceships.
  This essentially automates everything involved with getting the achievement so it's just a matter of time.
  
  I hope this was coherent and easy to follow, i'm sure in future updates it will be much easier to get this achievement but as of the 5/7/23 this is the easiest way i have found.
  
  Note: This is accumulated amount, you can spend the credits you earn and still hit the achievement, in the newer updates you can also find space credits through the portal generator that will greatly speed the process up, you can also find these space credits in the storage chests in warden areas, caves and on the surface of the planet. This Guide is still viable if you want to automate it but a few updates have come out since and its way easier to get it.