Steve's Space Program

Kerbal Space Program, but in Minecraft.

Every mod feature is listed below, but to summarize it all; You spawn in the overworld with nothing besides a space exploration manual. You can collect wood and stone to start regular tool progression, but as far as space goes there are 3 minerals you will need; Nickel, Steel, and Titanium all have their own set of space suits and tools. These minerals can also be used to craft Space Ships and other various space parts for complex rocket assembly. A space ship will allow you to simply launch into space, travel space, and land on different worlds. Space Ships will provide their own built-in radiation and temperature protection, but they do not provide oxygen. And for oxygen, the overworld is the only safe place unless you are around soul torches, soul lanterns, soul campfires, or unless you're wearing a space suit. Every space helmet and chest piece will provide oxygen, whereas the full set will provide temperature protection, and its own level of extra radiation protection. You will only need to worry about 4 things while living on a different world; Temperature, radiation, oxygen, and storms. All of the gas giants and ice giants as well as Venus have incredibly harsh storms, so if you get caught in one its likely wraps. Honestly, there is not much to explore in these other worlds, as expected right? I believe the true challenge of this modpack would be to inhabit every world there is, for example; The only saved world I included in this modpack is a small space station. Inside the space station your protected from everything, but outside of the space station are freezing temperatures and radiation exposure. Crops, players, and mobs can survive inside the space station but not outside. This can apply to every dimension, not just space. So if you wanted to, you can inhabit Venus, Europa, Jupiter, etc. as long as you have the correct resources for it. Certain blocks can emit certain temperatures for a set range of blocks, so keep that in mind if you plan to build a base/ship and want to keep your temperatures stable. Radiation exposure can be diminished with nether stars, beacons, and water. 

ALSO please try to not attempt travel to Dark Earth or J-1407B, this will result in your space nodule possibly deleting itself and you will be alone in space with nothing. I hope the Cosmic Horizon's developers will allow players to eventually go to these planets but for now they are inaccessible 

Important Mods:

Cosmic Horizons - Adds space, stars, planets, moons, etc. and allows the player to explore space manually

Thin Air - Made it possible for players to asphyxiate if they have no source of oxygen (Soul torches, lanterns, etc. can provide air)

Coldsweat - Every planet and moon has its own day/night temperature swings, I tried to make it as accurate as possible. Note that temperature affects both the player and all mobs

Coldsweat Limitation Crops - Crops can only grow in certain temperatures

Irradiated - Every planet and moon has its own radiation levels. You cannot reverse radiation poisoning; only can you prevent it (Beacons can protect you from radiation exposure within a 7-block range)

Create - You can create advanced machinery and automation systems to do literally anything you want. Addons include: CopyCat+, Connected, Steam 'n' Rails, Deco, Drive-By Wire, and The Factory Must Grow

Valkyrien Skies - Build and pilot fully functional moving ships and vehicles

Starlance - Adds spacecraft and space exploration technology (like thrusters, drag inducers, etc.) and makes it possible to fly VS ships into space

KubeJS - I had to create recipes for different mods so that this modpack can be possible to play in survival

Weather2 - Configured it to the best of my ability to allow our gas and ice giants (and Venus) storms and wind

Burnt - Realistic burning, forest fires and stuff. Pretty cool to watch it all burn but, be careful as fire spreads incredibly fast

Firstaid - No more hearts, you now have body parts you can heal with bandages and plasters

Not as Important Mods:

Epic Death Screen - Everything will simply just cut to black when you die, very cool mod

Jade - You can see what it is your looking at, with the addition that looking at crops will tell you what temperature is required for them to grow

Waystones - Just to make things a little faster

Seatbelt - Key Enter to fasten seatbelt (keeps you safely seated inside your ship)

Dynamic Crawling - Key X to crawl

Quickzoom - Key C to zoom

External View - NumPad2 to zoom in, NumPad8 to zoom out

Camera Overhaul - Adds to the realism, basically just view bobbing but realistic

Velocity Blur - Travelling at fast speeds will look like you're travelling at fast speeds. I hope this doesn't induce some kind of nausea though so please be aware of this mod

Dynamic Trees - Cool trees you can chop down, also compatible with burnt 

Get in the bucket - So you can easily transport your mobs to wherever you want

BadMobs - Hostile mobs like zombies, skeletons, creepers, etc. will not naturally spawn in the overworld anymore

Creative Flight Speed - If you just want to explore space in creative, I = decrease speed O = increase speed. You can go up to 40x the creative flight speed to make space travel a little faster

Portable Blueprints - You can use a blueprint to save and load your build wherever you want. Useful for creating world-dependent bases/stations in the overworld's safe conditions 

I hope this modpack is fun for everyone and if anyone has something to critic, or something is inaccurate, please comment or let me know as I can take criticism and improve from it.

Credits to EuphoriaLuna on Planet Minecraft for the Aurora Space Station build, I simply just modified it to fit space's conditions.

Link to the build: Aurora Space Station Minecraft Map