Yap, you can. But you need an updated Galaxy Forge and follow some instructions in order to do it. You can find all of this at reply #2482 from here https://forums.sinsofasolarempire.com/335474/page/100/#replies
As for assigning planetary bonuses. Open Galaxy Forge, select any planet and choose the edit option. Now, go to the Group Manager and click on Add. Now, look on the far right, at the list. You'll find all of them there, figuring that you followed my instructions.
Now, for what all the bonuses do -> Here's a list made by Stant123 :
Non-Colonizable Space Condition
Asteroid Belt (Dwarf/Huge) Erratic Debris (Chance to hit -20%)
Black Hole Grav damage 1/2 (range 16k/8k, dam 20/500), grav pull 1/2 (range 19k/10k, max speed +3k/6k, accel -3k/6k)
Deep Space Cabin fever (wep cool -15% wep range -15% dam out +10% hit chance -15% hull restore -5% shield restore -5% max speed -7% accel +7%)
Magnetic Cloud Abilities Disabled
Nebula Chance to hit -30%
Plasma Storm (Dwarf/Giant) Strike Craft Launch Disabled
Ship Graveyard
Space Junk (Dwarf/Huge) Scrap Materials (Hull Restore +10%)
Wormhole Wormhole Interference (Wep cooldown +5%, Chance to hit -5%)
Star Conditions: Target
Light Pulsar Radiation range 10000, damage 5 (Companion White)
Light Solar Radiation antimatter restored 1.3/sec (companion RedYellowGreenBlue)
Magnetic Storms Abilities Disabled (Blue Magnetar/Companion 2meta)
Pulsar Radiation range 10000, damage 10 (White)
Solar radiation antimatter restored 2.5/sec (RedYellowGreenBlue)
Planet Conditions: Target Function
Ancient Planetary Shield (Relic) All Cannot be bombarded or captured (4 min on/off)
Asteroid Debris All Wep Range +5%, Damage reduction -5%
Barren world All Hull restore +3/5%, Phase jump charge rate -3/5%
Careless targeting All Wep cooldown +5/8%, shield restore -5/8%
Extended hours All Wep cooldown -3/8%, Hull restore rate +3/8%
Free Reign All Hit Chance -5%, Hull Restore +5%
Huge Industrial Factories (indus) Friendly Ship build rate +40%
Mass Casualties All Wep cooldown -5/8/10%, damage reduction -5/8/10%
Origin Defense Friendly Damage Output+10%, Damage Reduction -5%
Overgrown Land All Max Speed +3/5/8%, Acceleration +3/5/8%, Phase jump charge time -3/5/8%
Paradise All Max Speed +15%, Acceleration +15%, Phase jump charge up rate +15%
Pirate Origins All Wep cooldown +5%, hit chance -5%
Solar Reflection All Antimatter restore .5/.8/1/sec, Wep Cooldown -5/8/10%
Storm Season (Swamps) All Uncolonizable (8 minutes on/off)
Targeting Array Network Friendly Weapon range +50/65%, Damage output +10/15%, Chance to hit +50/65%
Toxic Gases All Antimatter restore +.3/.8/sec, Shield mitigation -5/10%
Urban Colonization All Wep Range +3/5%, Max Speed -3/5%, Acceleration -3/5%
Violent Gases All Damage output +5%, Hull restore -5%
Volcanic Ions All Antimatter restore .5/.8/1/sec, Wep Range -5/8/10%
Exploration Bonus: Function
Abandoned Smugglers Base Tax income +1, trade income +40%
Active smugglers base tax income -2, trade income -60%
Adhesive resin trade incone +25%, dev build cost +10%
Ancient planetary shield (damaged) Planet health +700
Ancient planetary shield (working) Planet health +2000
Automated defense droids Max pop -100, Pop growth -100%
Beautiful population culture spread +40%, trade income +20%, pop growth +30%
Black Market (pirate) trade income +500%
Breathable Atmosphere Max pop +200, Dev build cost/rate +50%/+50%, pop growth +20%
Brilliantly designed buildings max pop +250, planet health +500, pop growth +20%
Caustic Atmosphere Max pop -15, Dev Built Cost -20%
Completely hollow core Gravity well radius -66%
Completely Overgrown Max pop -100, Planet health +800, Development build rate -90%, Pop growth -50%
Conductive Mantle Culture spread +25%
Constant flooding Max pop -20, dev build cost -40%, Dev build rate -40%
Construction Droids Struct Build rate +50%, Dev build rate +100%, Extra constructors +3
Corrosive atmosphere planet health -100, trade inc -1, dev build cost -50%
Deadly Secret Max Pop -1000, Planet health -10000
Dense Canopy planet health +600
Dense Jungle Max pop -10, Dev build rate -75%, Pop growth -30%
Dense Molten Core Grav well +33%
Diseased Planet Max pop -20, tax income -2, trade income -50%, struct build rate -100%, dev build rate -100%, pop growth -90%
Entertainment Hub Culture spread rate +10%, Tax income +1/sec
Expert Agrarian Society Trade income +10%
Expert metal miners metal extraction rate +50%
Expert crystal miners crystal extraction rate +50%
Extremely valuable timber trade income +50%
Floating Fauna Max Pop -5, Trade income +30%
Floating islands (Gas giant) Max pop +25
Foul Smell Culture spread -20%, Max pop -20, trade income -10%, Dev build rate -30%, pop growth -10%
Fresh water oceans max pop +50, trade income +75%, pop growth +30%
Frequent Meteorites (Asteroids) Max pop -20, Metal/Crystal extraction rate +30%
Friendly Religious Population Culture spread rate +60%, population growth +20%
Frozen gas core Max population +5, Planet health +300
Frozen over Dev build rate -75%
Galactic Trade Center (Urban) (normal/dwarf/giant/moon) Tax income +3/2/4/1/sec, trade income +40/30/50/30%, pop growth +20%
Gas storms Max pop -5, Planet health -200, pop growth -25%
Geothermal Hot Spots Logi slots +4
Giant Fungi Forests max pop -10, trade inc +40%, dev build cost -20%
Gravitational Anomoly Logi slots -4, Tac slots -5, Grav well raiis -100%
Gravitational Boon Logi slots +4, Tac slots +5, Grav well radius +100%
Habitable Cavern System max pop +15, Planet health +500
Helium Rich Atmosphere Trade income +25%
Hideous Population culture spread rate -20%, trade inc -50%, pop growth -30%
High security protocols Tac slots +5, Trade income -20%
Hostile Religious Population culture spread -30%, tax income -1
Huge Comm station array Culture spread +100%, Tac slots -8
Huge crystal processing plant trade income +10%, crystal extraction +200%
Huge herds of cattle max pop +40, tax inc +0.5, trade +20%, pop growth +20%
Huge metal processing plant trade income +10%, metal extraction rate +200%
Impure Crystal trade income -10%, crystal extraction rate -60%
Impure metal Trade income -5%, Metal extraction rate -60%
Indigenous Carnivores max pop -20, dev build rate -20%, pop growth -60%
Indigenous satellites Culture spread rate +20%
Industrial Wasteland Culture spread -30%, Metal/Crystal extraction rate +30%
Ionic Storms (Gas giant?) Max pop -20, Trade income +10%
Kalanite deposits trade income +20%
Massive Pure glaciers Trade income +30%
Mega Fauna Max pop -15, Trade income +25%
Militaristic population planet health +1000, log slots -4, tac slots +10, tax -2, trade -20%, extra constructors 1
Moon Logi slots +4, grav well +25%, Structure build rate +10%
Moons Logi slots +8, Grav well +50%, Structure build rate +20%
Natural Radiation Dev build rate -40%, Pop Growth -80%
Natural Thermal Lift Structure build rate +25%
Old military outpost Planet health +1000, tac slots +10, extra constructors +1
Orbital Construction Specialists Log/Tac slots +4, Struct build cost/rate +30/50%, Extra Constructors +2
Penal Colony Structure build cost +20%, Structure build rate -30%
Perfect holiday destination (paradise) Culture spread rate +100%
Persistent Dust Storms pop growth -25%
Pharmaceutical Flora Trade income +20%, Pop growth +20%
Planetary Construction Specialists Planet health +200, Development build cost/rate +30/+50%
Planetary Insurgency culture spread -20%, planet health -150, tax -2, trade -30%, metal/crystal rate -50%, struct/dev cost -20%, struct/dev rate -60%, pop growth -30%
Planetary revolt culture spread -10% planet health -100 tax -1 trade -10% metal/crystal rate -20% strct/dev build rate -30% pop grwth -10%
Pleasent Rodents culture spread +40%, trade +20%
Plundered booty (pirate) tax income +3.5
Porous Core Grav well -33%
Precious Stones Culture spread rate +20%, Logi slots +4, Trade income +50%
Priceless timber culture spread +20%, trade income +80%
Raiders Outpost Metal extraction +20%, Extra constructors 1
Scented plants Culture spread rate +20%, trade income +20%
Seismic Activity pop -20, planet health -100, tax -1, dev build cost/rate -30%/-10%
Signal interference Culture spread rate -20%
Slaves trade income +10%, struct build cost +30%, dev build cost/rate +50%/+20%
Solar Energy Harvesting Max pop +15
Space Ponies Space Ponies!
Spice trade Culture spread rate +5%, Trade income +10%
Stable Debris Field trade income +20%
Storm ridden planet max pop -50, dev build cost/rate -20%, pop growth -40%
Strong Building Materials planet health +500, trade income +10%, dev build rate -20%
Submerged colony Max pop +140, Planet health +800
Subterrainian Colony Max pop +80, Planet health +1500
Super Dense Core grav well radius +66%
Super Pure Crystal Crystal Extraction rate +200%
Super Pure Metal Metal extraction rate +200%
Thaw Cells max pop +25
Thick Atmosphere Planet health +1200
Tibanna gas (gas giant?) tac slots +2, trade income +5%
Toxic Fallout Max pop -30, Pop Growth -25%
Traces of oxygen Max pop +50, pop growth +20%
Tundra Farms Max pop +25
Unstable ground Dev build cost/rate -50%/-20%
Valuable timber Trade income +30%, Dev build cost +10%
Vermin Infestation Tax income -1, trade income -30%, Dev build cost/rate -20%/-20%
War torn planet culure spread -40%, planet health -200, logi/tac slots -4/-6, trade/metal/crystal -30%/-20%/-20% struct build -40%, dev build/cost -20%/-60%, pop growth -50%
Weapons test facility Max pop -20, Tac slots +8
Well designed buildings Max pop +100, planet health +200
