Full list of all 71 Mars Horizon achievements.
The base game contains 65 achievements, and there are 2 DLC packs containing 6 achievements.
Win the Race to Mars with all 5 space agencies
Complete every other Mars Horizon achievement
Win the Race to Mars on hard difficulty or above
Win the Race to Mars on very hard difficulty
Finish 1st in every Milestone mission in a single game on normal difficulty or above
Succeed a launch using an N1 booster
Complete a Joint mission with an Antagonistic agency
Launch any vehicle except Sounding Rocket with 50% or lower Launch Reliability
Complete a mission using an astronaut above the age of 70
Complete a mission task with 1% Payload Reliability at the end of it
Land humans on Mars in a Joint mission with another agency
Complete a mission task with 30 or more Thrust
Send an astronaut on a mission one month before their retirement
Complete a Publicised Request Mission using a Celebrity astronaut
Complete a mission task with 50 or more Data
Launch a human into Earth orbit before April, 1961
Complete a mission with a Payload that has 50% or lower Payload Reliability
Place an Artificial Satellite in orbit before October, 1957
Complete every Milestone mission in a single game
Complete the Grand Tour
Become Allied with all other agencies
Complete a mission task with 50 or more Comms
Explode a Sounding Rocket
Land humans on Mars
Win the Race to Mars
Complete all 4 Mars Preparation missions
Have a single building with 6 active Positive Adjacency effects
Land an Exploratory Rover on Mars
Complete a flyby of Pluto
Complete every Research in every Research Tree in a single game
Complete every Research in the Missions Tree
Complete the Bonus Objective of a mission task that involves Heat
Complete missions to every planet in the Solar System in a single game
Complete a mission task that requires Drift to be exactly 0
Complete a Modular Space Station
Hire a Tier 3 astronaut
Complete every Research in the Buildings Tree
Launch a Space Telescope into orbit
Complete every Research in the Vehicles Tree
Complete a mission to any of the Outer Planets
Launch a mission using a reusable spaceplane
Successfully launch a vehicle in Terrible conditions
Achieve a mission task's Bonus Objective with the last Command of the last turn
Remove every obstruction from your base
Complete a mission with a Payload that has 99% Payload Reliability
Complete the Crewed Moon Landing mission
Complete the Crewed Moon Landing mission before July, 1969
Land on the Moon before any other space agency
Complete Human in Space, Orbital EVA, Mulitcrew Orbit, and Crewed Moon Landing using the same astronaut
Launch a crewed moon mission using a Saturn V booster
Complete a Joint Mission
Construct a small, medium, and large launchpad
Launch any vehicle except Sounding Rocket with 99% Launch Reliability
Reach the maximum Experience Level for a vehicle part
Launch a vehicle with a 1% chance of Critical Failure... which explodes
Complete an Orbital EVA
Complete every Bonus Objective on a mission with at least 3 tasks
Complete a mission to any of the Inner Planets, excluding Earth
Launch a human into Earth orbit
Unlock an Era Completion reward in a Research Tree
Launch an animal into Earth orbit
Complete a Challenging Request Mission
Complete all Tutorial Objectives
Place an Artificial Satellite in orbit
Complete the Bonus Objective of a mission task
Successfully land a reusable rocket
Win the race to Mars on Iron Core
Fly a helicopter on Mars?!
Explore Mars using the Zhurong Rover.
Successfully complete the Space Tourism request mission
Successfully completed the Philae Landing mission.