I'm working on a Galacticraft-like Datapack. Feel free to use it in your worlds (1.19).

Pack features (28/08/22) :

- Fully working custom rocket that you can build yourself with your blocks
- Space dimension with weightlessness (shift to go down/shift+looking up to go up)
- Oxygen generator, gear, damage
- Works on multiplayer except being 2 in the same rocket
- Planet add-on friendly

Future features :

- Other vegetation in the oxygen collector
- I'll try to make it so that closed environnements can be breathable in space
- Moon, Mars, etc with custom worldgen and gravity
- Custom rocket patterns findable on planets

If you have any ideas for other features, do not hesitate to tell me in the comments

How to use the rocket :

- Craft the seat with the screen above
- Place the egg where you want your seat to be
- Build your rocket around your seat. Be aware of the spheric limit. Building beyond it won't take your build as a part of your rocket!
- Press the button without being in the seat to destroy the seat (and get back the egg)
- Press the button while being in the seat to launch the rocket
- If it does not launch, check if there are enough coal blocks/hoppers on your build. You can try removing some blocks for less weight. You can refer to the percentage "flying potential" to see if you're doing good
- If you are in space, choose your destination in chat before launching the rocket (or you will get back to space)
- When you go back on earth, fuel (coal blocks) is used

How to use the oxygen collector :

- Craft it with the screen above
- Craft a Space Helmet with the screen above
- Place the collector
- If you're on earth, just place the helmet on the armor stand and it will refill easely
- If you're in space, place the helmet on the armor stand and put oak leaves inside the collector
- Does not work if you disabled the doDayCycle gamerule

How to add your custom planet as an add-on datapack (example for "add_on:venus" dimension, n°111) :

1. Create a landing function (for example "venus_landing.mcfunction") and write inside :

• function mitspace:landings/general
• execute as @e[​distance=..17 if score @s mitspace_rocket_id = @e[​tag=mitspace_landing,sort=nearest,limit=1] mitspace_rocket_id] at @s in add_on:venus run tp ~ ~ ~

2. Create a predicate (for example "is_on_venus.json") to know if a player is on Venus :

{
"condition": "entity_properties",
"entity": "this",
"predicate": {
"location": {
"dimension": "add_on:venus"
}
}
}

3. Write in your tick tagged function :

• execute as @e[​tag=mitspace_launched,tag=!mitspace_landing] at @s if score @s mitspace_rocket_seat_y_level matches 320.. if predicate mitspace:is_in_space if entity @p[​distance=..0.4] if score @p mitspace_planet_choice matches 111 in mitspace:space run function add_on:venus_landing
  
• execute as @a at @s if predicate add_on:is_on_venus run scoreboard players set @s mitspace_can_breath 0 #set to 1 if there is oxygen
• execute as @a if score @s mitspace_arrive_in_space matches 1 run tellraw @s {"text": "Choose Venus","color": "#e57f05","bold": true,"hoverEvent": {"action": "show_text","value": {"text": "Click!","color": "#e57f05"}},"clickEvent": {"action": "run_command","value": "/scoreboard players set @s mitspace_planet_choice 111"}}
  

4. Enjoy!

Mitchifs ;)