Scanning planets in Mass Effect 3 is important because you can pick up a whole host of items that contribute to Shepard’s credits total, XP and also the Galaxy at War total.
A lot of the universes aren’t accessible until you hit the first major plot point in Mass Effect 3, with the final set of universes not made available until you hit the second major plot point. Bear this in mind when scanning.
Artifacts aren’t useful in and of themselves but once you’ve picked up a few, return to the Citadel and explore all five floors. You’ll come across characters who the artifact can be sent to in return for credits and XP.
Items that count as upgrades for Shepard such as Reaper remains or intel can be used by accessing the third floor of the Normandy and entering Liara’s office (next to the kitchen). She has a terminal that enables you to select an upgrade and apply them to Shepard. They’re not huge bonuses and tend to offer 5% increases on shields, power cooldown and the like but it’s worth picking up.
Salvage will count as credits while Wreckage gives you more fuel for the Normandy.
If you scan too many times, the Reapers will turn up and start chasing you. All you have to do is exit that galaxy by crossing the green line. If you re-enter, the Reapers will start chasing you all over again but you’ll have a few seconds to grab any items you missed or scan again. If the Reapers catch you, it’s an instant game over, but they’re easy enough to avoid that this shouldn’t be a concern.
You also get an Achievement or Trophy for picking up 10 items from space by scanning.
Here’s every resource or upgrade you can collect from planet scanning, listed by galaxy and planet:
SIGURD’S CRADLE
SKEPSIS
Watson – Javelin Missile Launchers
Between Crick and Mass Relay – Wreckage
DECORIS
Laena – Salvage
South between second and third ring – Wreckage
ARCTURUS STREAM
ARCTURUS
Arcturus Station – Intel from battle of Arcturus
West of Themis – Wreckage
EULER
East of Fermi – Wreckage
GEMINI SIGMA
HAN
Underneath Mass Relay – Wreckage
Mavigon – Salvage
MING
Below Antiropus – Wreckage
Parag – Alliance Cruiser Nairobi
HADES GAMMA
ANTAEUS
Just underneath Mass Relay – Wreckage
Trebin – Salvage
PLUTUS
Nonuel – Special Ops Team Zeta, 103rd Marine Division
DIS
Right of the sun – Wreckage
Klensal – Salvage
FARINATA
North of the sun – Wreckage
Juntauma – Alliance Frigate Agincourt
CACUS
Chohe – Salvage
Far North-West – Wreckage
KITE’S NEST
HARSHA
Verush – Weapon Upgrade Kit
Left of Verush – Wreckage
Khar’shan – Artifact: Pillars of Strength
UNTREL
Adek – Salvage
West of Adek – Wreckage
ARGOS RHO
HYDRA
South of the sun – Wreckage
Canrum – Haptic Optics Array
PHOENIX
Pinnacle Station – Turian Spec Ops Team
Intai’sei – Artifact: Fossilized Kakliosaur
North-West of Intai’sei – Wreckage
GORGON
Camaron – Advanced Power Relays
APIEN CREST
CASTELLUS
South of Fiax, East of Nius – Wreckage
Digeris – Artifacts: Banner of the 1st Regiment
GEMMAE
Pheiros – Turian 79th Flotila
South of Pheiros – Wreckage
West of Pheiros – Wreckage
AETHON CLUSTER
ARU
Irune – Artifacts: Book of Plenix
West of Irune – Wreckage
Cherk Sab – Volus Fabrication Units
ESORI
Solu Paolis – Volus Dreadnought Kwonu
East of the sun – Wreckage
SATU ARRD
Nalisin – Volus Engineering Team
South-West of the sun – Wreckage
NURA
Oma Ker – Volus Intelligence Archives
North of the sun – Wreckage
ATTICAN BETA
HERCULES
Eletania – Interferometric Array
South-East of the sun – Wreckage
THESEUS
Feros – ExoGeni Scientists
North-west of the sun – Wreckage
THE SHRIKE ABYSSAL
XE CHA
Zada Ban – Salvage
South of the sun – Wreckage
URLA RAST
Talis Fla – Artifact: Prothean Obelisk
North-West of the sun – Wreckage
VALHALLAN THRESHOLD
RAHEEL-LEYYA
North-East – Wreckage
PAZ
Garvug – Artifact: Prothean Data Drives
East of the sun – Wreckage
MICAH
Elohi – Emergency Fuel Pods
Farlas (East, in asteroid belt) – Element Zero Convertor
South-East of the sun – Wreckage
HADES NEXUS
HEKATE
South-West of Mass Relay – Wreckage
Asteria – Alliance Frigate Hong Kong, Alliance Fifth Fleet
HOPLOS
Kopis – Artifact: Obelisk of Karza
Far West – Wreckage
SHEOL
Gei Hinnom – Artifact: Prothean Sphere
PAMYAT
Dobrovolski – Alliance Friage Leipzig, Alliance First Fleet
South of the sun – Wreckage
MINOS WASTELAND
FORTIS
Pietas – Salvage
South of Mass Relay – Wreckage
EXODUS CLUSTER
UTOPIA
South of Eden Prime – Wreckage
Zion – Prothean Data Files
ASGARD
Borr – Remains of Reaper Destroyer
Tyr – Alliance Naval Exploration Flotilla
Terra Nova – Alliance Cruiser Shanghai
Loki – Alliance Spec Ops Team Delta
North-East of the sun – Wreckage
SILEAN NEBULA
KYPALADON
Hanalei – Dr. Jelize
TEYOLIA
Nevos – Artifact: Rings of Alune
Quirezia – Salvage
East of the sun – Wreckage
PHONTES
Dekuuna – Artifact: Code of the Ancients
Oltan – Elcor Flotilla
East of Lenamund – Wreckage
NAHUALA
Hyetiana – Serrice Guard
South-West of Agessia – Wreckage
LOROPI
East of Wreckage – Wreckage
Yasilium – Armali Sniper Unit
NIMBUS CLUSTER
PELION
South of Aitis – Wreckage
Trategos – Intact Reaper Weapon
Just North-East of Trategos – Wreckage
Just North-West of Sthenia – Wreckage
AGAIOU
Carcosa – Artifact: Library of Asha
KALLINI
South of Pania – Wreckage
NUBIAN EXPANSE
DAKKA
Pragia – Research Data from Pragia
South-East of the sun – Wreckage
QERTASSI
Norehsa – Alliance Frigate Trafalgar
North of Norehsa – Wreckage
KALABSHA
Yamm – Alliance Marine Recon Unit, 103rd Marine Division
North-East of the sun – Wreckage
HOURGLASS NEBULA
OSUN
Erinle – Salvage
South-West of Erinle – Wreckage
FARYAR
Alingon – Shadow Broker Starship Tech
Next to Alingon – Wreckage
SOWILO
Hagalaz – Shadow Broker Support Team
North of the sun – Wreckage
PLOITARI
Zanethu – Terminus Freighters
ATHENA NEBULA
PARNITHA
Tevura – Asari Cruiser Cybaen
ORISONI
Egalic – Asari Research Ships
East of the sun – Wreckage
TOMAROS
South of Niagolon – Wreckage
Pronoia – Asari Cruiser Nefrane
VERNIO
Polissa – Artifact: Hesperia Period Statue
North-West of the sun – Wreckage
IALESSA
West of the sun – Wreckage
Trikalon – Asari Engineers
ISMAR FRONTIER
AQUILA
Metaponto – Advanced Biotic Implants