Full list of all 65 Mars Horizon achievements worth 1,180 gamerscore.
The base game contains 59 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 6 achievements worth 180 Gamerscore.
Complete every Milestone mission in a single game
Win the Race to Mars
Land humans on Mars
Complete the Grand Tour
Complete all 4 Mars Preparation missions
Land an Exploratory Rover on Mars
Complete every Research in every Research Tree in a single game
Complete every Research in the Missions Tree
Launch a Space Telescope into orbit
Complete a Modular Space Station
Launch a vehicle with a 1% chance of Critical Failure... which explodes
Complete the Bonus Objective of a mission task that involves Heat
Succeed a launch using an N1 booster
Have a single building with 6 active Positive Adjacency effects
Complete a mission task that requires Drift to be exactly 0
Complete a mission to any of the Outer Planets
Complete a mission with a Payload that has 50% or lower Payload Reliability
Complete Human in Space, Orbital EVA, Multicrew Orbit, Crewed Moon Landing with the same astronaut
Complete every Research in the Vehicles Tree
Launch a mission using a reusable launch vehicle
Hire a Tier 3 astronaut
Remove every obstruction from your base
Complete a Joint Mission
Complete every Research in the Buildings Tree
Land on the Moon before any other space agency
Launch a crewed moon mission using a Saturn V booster
Complete an Orbital EVA
Complete every Bonus Objective on a mission with at least 3 tasks
Construct a small, medium, and large launchpad
Complete a mission with a Payload that has 99% Payload Reliability
Complete a mission to any of the Inner Planets, excluding Earth
Successfully launch a vehicle in Terrible conditions
Reach the maximum Experience Level for a vehicle part
Launch an animal into Earth orbit
Unlock an Era Completion reward in a Research Tree
Complete a Challenging Request Mission
Achieve a mission task's Bonus Objective with the last Command of the last turn
Complete the Bonus Objective of a mission task
Place an Artificial Satellite in orbit
Launch any vehicle except Sounding Rocket with 99% Launch Reliability
Explode a Sounding Rocket
Complete every other Mars Horizon achievement
Launch a human into Earth orbit before April, 1961
Complete the Crewed Moon Landing mission before July, 1969
Finish 1st in every Milestone mission in a single game on normal difficulty or above
Land humans on Mars in a Joint mission with another agency
Launch any vehicle except Sounding Rocket with 50% or lower Launch Reliability
Complete a Joint mission with an Antagonistic agency
Complete a Publicised Request Mission using a Celebrity astronaut
Complete a mission using an astronaut above the age of 70
Send an astronaut on a mission one month before their retirement
Become Allied with all other agencies
Complete a mission task with 30 or more Thrust
Complete a mission task with 50 or more Data
Complete a mission task with 50 or more Comms
Complete a mission task with 1% Payload Reliability at the end of it
Win the Race to Mars on hard difficulty or above
Win the Race to Mars on very hard difficulty
Win the Race to Mars with all 5 space agencies
Fly a helicopter on Mars?!
Successfully land a reusable rocket
Win the race to Mars on Iron Core
Successfully completed the Philae Landing mission.
Successfully complete the Space Tourism request mission
Explore Mars using the Zhurong Rover.