Here is the full list of all 18 Starscape achievements.
Defensive shields
For rescuing 5 missing crew members
For rescuing 10 missing crew members
For rescuing 15 missing crew members
For rescuing 20 missing crew members
For rescuing 25 missing crew members
Drone weapons
Ion weapons
Nova bomb
Particle lasers
Zone 1 complete
Zone 2 complete
Zone 3 complete
Zone 4 complete
Zone 5 complete
Game completed on easy difficulty
Game completed on normal difficulty
Game completed on hard difficulty