Here is the full list of all 32 Ghost Signal: A Stellaris Game achievements.
Reach map 3
Reach map 5
Clear the game
Die 20 times
Discover 50 different components
Unlock 30 research nodes
Mine 100 resource asteroids
Mine 250 resource asteroids
Employ all 3 Tinkerers in the same journey
Scan 4 different creatures in the same journey
Have 4 defects simultaneously equipped in the same journey
Clear the game after clearing 5 Elite Battles in the same journey
Clear the game without having more than 6 components simultaneously equipped
Clear the game without upgrading any components
Clear the game without spending any scrap
Clear the game under 45 minutes
Reach the hidden burial chamber
Discover the truth about the blizzard on the frozen world
Spare the pirates after the first battle
Convince the mercenary to let you pass without paying
Save the trading vessel
Help both Blarg and Glouk
Get ripped-off at the repair station
Assist the priest 3 times
Make 2 or more Hammerhead enemies collide
Utilize the Aurora Thrusters 100 times
Defeat a boss using Meteor Thrusters
Strike enemies 50 times with Blink Thrusters' explosives
Poke VIR 5 times
Activate all threat levels at once!
Discover the fate of the Heralds
Reach an ending