The balance here is subject to change, I wanted to try out the general ideas first.

# Planets

Random planets that contain unique loot and are rotated every week or two. Sometimes there is no planet at all, but at most there is one planet at a time.

Planet type is selected from the following list, and will exist from 3 to 7 days. A new planet will spawn after an additional 2 to 14 days.

Planets also contain abundant hostile mobs which can be very powerful, making them difficult to loot.

The size is randomised, between 1000 blocks and 3000 blocks radius.

All planets should have at least a small supply of wood and stone to make factories.

### Mangrove swamp planet

Consists of only the mangrove swamp biome. It has abundant crude oil deposits (Y -16 to 16), critical for space exploration. Redstone ore is especially abundant here, being found on all Y levels, and other ores can be found at reduced rates. Pumpkin, melons, and sweet berries grow in 1 hour here.

### Cherry grove planet

Consists of only the cherry grove biome. Crude oil can be found in small deposits, but this planet is especially rich in iron ore. Other ores can be found at reduced rates. Killing mobs here has a 0.075% chance of dropping a totem of undying, but only one can be dropped per planet. This planet grows wheat, carrots, potatoes, and beetroot within 1 hour. Dead bushes found here drop *ancient wood*, an essential ingredient in hyperweave armour.

### End planet

This consists of end cities, and shulkers can be found here. Diamond ore is also present beneath the surface, at 125% of overworld rates. No other ores are present. Two random end cities will have a shulker shell. All nether crops grow here with 1 hour growth times.

### Ocean planet

A mix of beaches and oceans, this planet also has some palm trees. It contains dozens of ocean ruins. Sugar cane, kelp and cocoa grow within 1 hour here. Redstone ore is plentiful, as well as ancient debris at 125% of the rate in the nether. Other ores can be found at lower rates. This planet also has a special type of sea pickle named *Samphire* on the ocean floor, used for crafting hyperweave. (Should this be a mob drop instead? Sea pickles might be too easy to loot)

### Forested planet

This planet is a mix of taiga, snowy taiga, birch forest, regular forest, and jungle. It's perfect for finding trail ruins, a source of unique items. It's also the only place to get hyperweave fibers. Feeding a spider acacia leaves, then killing it after at least 5 minutes, has a 10% chance of dropping one. This planet grows all saplings except acacia in 1 hour. All ores found in the overworld can also be found here at regular rates.

### Mountainous planet

This planet only contains extreme cliffs. Goats can be found here, as well as smithing templates that can't be found anywhere else. All ores drop at 105% of normal rates. This planet also contains 2-3 deep dark biomes.

## Slowing people down

These new planets are foreign, and should be hard to explore, and there should be ways to prevent them from being looted very quickly. Planets can have different hazards that require different mechanics to overcome, but can only be discovered once you get to the planet. (You can "Conduct planetary analysis", but this only has a chance of telling you anything)

The hazards are generated randomly, and there may be multiple hazards on a planet. You will only be able to protect yourself from one or two hazards at a time, making some planets more dangerous than others.

### Hazards

- Atmosphere (40% Thin, 20% Normal, 40% Thick)
- A thin atmosphere requires an oxygen tank, which only needs to be in your inventory to be effective. It requires a refuel of Oxygen (generated from Brewery) every 10 minutes. If the oxygen tank is empty, the player will begin suffocating quickly.
- Oxygen tanks have durability and will last 120 uses, or 20 hours.
- The intention of this mechanic to force the player to use up inventory slots, reducing how much they can carry between planets.
- Brewery should be disabled on planets to force Oxygen to be brought on rockets.
- A normal atmosphere has no special effects.
- A thick atmosphere reduces speed by 50%.
- The speed debuff can be reduced by 10% for each peace of hyperweave armour (scaled linearly based on thickness, 10% at -1 thickness, 2% at 0 thickness, 0% at -1 thickness).
- Temperature (40% Low, 20% Normal, 40% High)
- Low temperature causes occasional freezing for 20-40 seconds every 2-3 minutes. Full hyperweave armour can reduce this to only once every 10-15 minutes (scaled linearly based on thickness, 10-15 minutes at 1 thickness, 4-6 minutes at 0 thickness, 2-3 minutes at -1 thickness). Speed is reduced by 80% while freezing, and jumping is not possible (only possible with 1.20.5). You will also not be able to swim up while freezing.
- Normal temperature has no special effects.
- High temperature needs active cooling, and you must have an Active Cooling Unit on you, which consumes Ice from your inventory to cool you, and also uses empty buckets. It uses 32 ice every 5 minutes, and every 16 pieces of ice used drops a lava bucket. Blue ice is is 8 times more expensive, but keeps you cool for 20 minutes per 32 blue ice, and also drops lava buckets.
- Active Cooling Units have durability and will last 80 uses of either ice or blue ice.
- Gravity (30% Low, 30% Normal, 40% High)
- Low gravity makes your normal jump height 3 blocks (only possible in 1.20.5), and gives a random effect (mining fatigue, hunger, poison, weakness) for 30 seconds every 4 minutes. Hyperweave armour increases the interval by 1 minute for each piece, up to 8 minutes.
- Normal gravity has no effects.
- High gravity means that players can only jump up half a block. Full hyperweave armour will restore regular jump height, or people can use potions of leaping (only level 2 should work for a full block).
- Gravity also affects the amount of fuel required to leave the planet.

## Hyperweave armour

Hyperweave armour is a new space-era tier of armour that can greatly withstand environmental hazards. It is not very good in PvP but excellent in PvE. The reason why it will be bad in PvP is because it will not have any enchants like Protection 4. Enchanting will instead be completely reworked.

The intention here is to make it useful for some planetary hazards, but also useful in the overworld to deal with mobs, or just for general use, as an alternative to netherite/diamond.

It is also bound to people.

### Crafting

Hyperweave armour will require a special hyperweave armour factory which produces hyperweave fragments from exotic materials found on various planets. The recipe is described in the "Factories" section.

### Effects

It is equivalent to diamond armour, but has some other modifiers.

With full hyperweave armour:

- Mob damage is reduced by 40% (this should be balanced to be somewhat better than prot 4 netherite armour, since this won't have protection)
- Boots are equivalent to feather falling 5
- Helmet is equivalent to respiration 4 and aqua affinity.
- All pieces have thorns 3 and durability is not affected if thorns is activated. This can be disabled with a /config setting.
- All pieces have unbreaking 2 and can be repaired normally with the normal limits on repair times (but with the thickness mechanic).

### Thickness

By default, hyperweave armour has a thickness of 0. Enchanting it will randomise thickness between -1 and 1, with a normal-like distribution centred on 0.

Two pieces of hyperweave armour can be combined in an anvil to improve its thickness. Armour with negative and positive thickness cannot be combined (combining with unenchanted, and therefore 0 thickness armour will not affect the thickness).

The formula for combining hyperweave armour shall be as follows:

$$
x = \sqrt{x(x+(1-x)^ky)}
$$

Where x = the hyperweave piece that should be improved, y = the sacrificed hyperweave piece, and k = 1. k can be increased to make it harder to produce higher thicknesses, pending playtesting.

The formula will make it hard to produce armour of extreme thickness. For instance, combining two 0.2 thickness armour will produce 0.27 thickness, and combining two 0.8 thickness will produce 0.87 thickness. Combining a 0.2 thickness and a 0.8 thickness will produce 0.82 thickness.

Low thickness will provide better mobility in thick atmospheres, but high thickness keeps you warm in cold planets. 0 thickness provides a small amount of protection from both. This is the tradeoff players will need to make.

## New resources

### Crude oil

Crude oil can be found rarely in the overworld, at the cracks between the deepslate and stone layer, between -16 and 16 Y. It is necessary for space travel. It is represented by black dye. It drops 1-64 items per ore.

### Petroleum

Petroleum is a refined version of Crude Oil, and for fueling rockets. It can only be manufactured in the Petroleum Factory and is represented by orange dye.

### Hyperweave fragment

Hyperweave fragments can be produced on the Cherry Grove Planet.

## Factories

### Hyperweave Armour Factory

128 hyperweave fibre, 64 *Samphire*, 112 *ancient wood*, and 6 petroleum to create.

#### Hyperweave fabric

16 hyperweave fibre, 8 *Samphire*, 14 *ancient wood*, and 3 petroleum produce 1 hyperweave fabric

### Hyperweave armour

2 sets of diamond armour, and 48 hyperweave fabrics, produce 2 sets of hyperweave armour.

### Petroleum Factory

Requires 2 stacks crude oil, 16 coal blocks, and 64 essence to create (it's cheap, you're meant to make A LOT of these).

#### Petroleum

8 stacks crude oil and 2 essence produces 1 petroleum, using 6 stacks of charcoal over 3 hours.

#### Efficient petroleum

2 stacks crude oil, 4 essence, and 31 petroleum produces 32 petroleum, using 7 stacks of charcoal over 1 hour.

(This recipe is meant to make it less efficient to set up petroleum refineries on other planets, instead encouraging you to bring it back to your main production facility.)

### Space Factory

Requires 128 iron blocks and 128 redstone blocks to create.

#### Active Cooling Unit

1 beacon, 64 iron, and 64 redstone blocks produces 4 active cooling units.

#### Oxygen Tank

64 iron blocks, 64 gold blocks, and 64 redstone produce 4 oxygen tanks.

#### Manufacture rocket

16 stacks of copper blocks, 64 amethyst blocks, 256 glowstone blocks, 1 stack of iron blocks, 32 diamond blocks produce 3 rockets.

### Spacepad Factory

This is a small factory that is easy to build, so you can launch your rocket from the planet you landed on. Requires 64 copper blocks and 64 lapis blocks to build.

#### Conduct planetary analysis

This recipe costs 1 diamond, and has a 1/5 chance of telling you each of the following pieces of information:

- Planet type
- Planet temperature
- Planet atmosphere
- Planet gravity

This information is the same however many times this recipe is run for an individual planet. Note that there's only a 60% chance of getting any information at all.

If the planet will disappear in less than 36 hours, it will tell you exactly when it will disappear. If there is no planet, it will tell you when the next one will appear if it will appear within 36 hours.

#### Refuel rocket

This is a custom recipe that takes a rocket, and petroleum, and adds it to the rocket. There is no limit to how much fuel a rocket can take, it just can't be removed.

#### Conduct pre-launch checks

This recipe can optionally be run before the "Launch rocket" recipe. It will calculate how many players are nearby the factory, sum the total launch mass, and display the fuel required to the player.

#### Launch rocket

This is a custom recipe that will launch the rocket, containing the player who started the factory and ALL of the items in the factory's input chest, which will be launched with the rocket. ~~It's important that this is limited to only the chest the rocket is in, otherwise people will be able to add too much.~~ All players within 5 blocks of the factory will be launched with the rocket. Launching will fail if the rocket is not fuelled sufficiently, and no fuel will be used.

## Rockets

All rockets contain ~~a double chest of~~ inventory space, but require fuel.

Every item that the player carries, as well as anything stored in the rocket, will require additional fuel. Every full inventory slot is considered to weigh 1kg (eg - 1 diamond sword is 1 kg, 16 empty buckets is 1kg, 1 water bucket is 1 kg, 64 cobblestone is 1kg, 32 cobblestone is 0.5kg). Compacted items are also given a commensurate mass, as are shulker boxes.

A rocket can be used a maximum of 6 times, for 3 trips there and back.

The player and the rocket is considered to weigh 100kg (this is the minimum launch mass). Additional players are considered to weigh 50kg.

#### Fuels

Petroleum is an exception to the above calculation and is considered to weigh 100kg per item. Crude oil is also considered to weigh 0.8kg per item.

(TODO Crude oil weighs way too much, making it uneconomical to bring back. Perhaps make it easier to refine on other planets? Then bump up crude oil up to ridiculous quantities on other planets, people will lose 90% on the way back but it would still be better)

Make sure to bring enough for the return journey! You will need far more fuel to return than to send your rocket out.

#### Efficiency

The efficiency of a rocket is a percentage of the rocket that is usable mass. The rest must be fuel.

The ∆v to leave the overworld or a planet is 10,000m/s. This requirement is decreased to 8,000m/s if you are leaving a low gravity planet, and increased to 12,000m/s on high gravity planets. Rockets require fuel to leave the overworld, and also fuel on the return journey back to the overworld. Every additional item you return from other planets costs you fuel on both journeys, so be careful with what you bring back!

The petroleum engine on the base rocket has an exhaust velocity of 5,000m/s.

According to the Tsiolkovsky rocket equation, this means that the following percentage of fuel is required:

| Low Gravity | Normal Gravity | High Gravity |
| ----------- | -------------- | ------------ |
| 79.9% | 86.5% | 91% |

The following table shows examples of how much fuel is required for two trips with a rocket, with an outgoing payload and return payload. It assumes that the outgoing trip is at normal gravity, and shows how much fuel is required for different returning gravities. It assumes that all the fuel is provided at the start of the trip, without any refueling.

| Rocket | Payload | Return payload | LowG fuel (items) | NormalG fuel (items) | HighG fuel (items) |
| ------ | ------- | -------------- | ----------------- | -------------------- | ------------------ |
| 100kg | 0 | 0 | 3165kg (32) | 4721kg (48) | 7043kg (71) |

## Appendix

Unused items:
- Totem of undying
- Shulker boxes
- Smithing templates
- bundles
- allays
- goat horn
- sculk sensor
- warden boss
- swift sneak
- Deep Dark Biome
- Armour trims
- Archaeology
- cherry blossoms/biome
- Breeze mob/windcharge item
- Sponges (currently bastions can work as sponges and wet sponges just drop bastions, but we should fix this behaviour and add real sponges)

Here is a Python script that can calculate fuel required for a launch:

import math

rocket_mass = float(input("Rocket mass: "))
payload_mass = float(input("Payload mass: "))
return_payload_mass = float(input("Return payload mass: "))

exhaust_velocity = 5000
normal_delta_v = 10000
normal_g = math.exp(-normal_delta_v / exhaust_velocity)

for name, delta_v in [("Low", 8000), ("Normal", normal_delta_v), ("High", 12000)]:
    g = math.exp(-delta_v / exhaust_velocity)
    return_payload_fuel = (rocket_mass + return_payload_mass) / g - (rocket_mass + return_payload_mass)
    payload_fuel = (rocket_mass + payload_mass + return_payload_fuel) / normal_g - (rocket_mass + payload_mass + return_payload_fuel)

    print(f"{name} gravity: {math.ceil(payload_fuel)}kg ({math.ceil(payload_fuel/100)})")