scifi:spacecraft
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scifi:spacecraft [2019/11/23 22:38] – sam | scifi:spacecraft [2020/04/26 10:27] – sam | ||
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The statistics used are simplified from real world values to make the maths of designing craft easier. Mostly, this involves including all the constants in the basic statistics. | The statistics used are simplified from real world values to make the maths of designing craft easier. Mostly, this involves including all the constants in the basic statistics. | ||
+ | |||
+ | Full statistics for some component designs are available here: | ||
+ | * [[./ | ||
===== Definitions ===== | ===== Definitions ===== | ||
- | **Mass**: Total size of the vehicle, in // | + | **Displacement**: Total size of the vehicle, in // |
+ | |||
+ | **Mass**: The actual mass of the vehicle in metric tonnes. This can get complicated, | ||
**Thrust**: How powerful a drive is, per displacement tonne. The higher this is, the faster a spacecraft can accelerate. This is based on Newtons of force produced by the drive, multiplied by a magic number. | **Thrust**: How powerful a drive is, per displacement tonne. The higher this is, the faster a spacecraft can accelerate. This is based on Newtons of force produced by the drive, multiplied by a magic number. | ||
**Impulse**: | **Impulse**: | ||
+ | |||
+ | **Delta-vee**: | ||
The **Total Thrust** is the thrust of the engines times their total mass. | The **Total Thrust** is the thrust of the engines times their total mass. | ||
The **Acceleration** is the **Total Thrust** divided by the **Ship Mass**, in m/s². | The **Acceleration** is the **Total Thrust** divided by the **Ship Mass**, in m/s². | ||
+ | |||
^ Engine | ^ Engine | ||
- | | F-1 (LOX/ | + | | F-1 (LOX/ |
- | | J-2 (LOH) | 1 | 1,000 | 421 | | | + | | J-2 (LOH) | 1 | 1,000 | 421 | 1000 | |
- | | Raptor (LOX/RP1) | 1 | 2,400 | 380 | | | + | | Raptor (LOX/RP1) | 1 | 2,400 | 380 | 2400 | |
- | | Merlin (Methane) | 1 | 981 | 311 | | | + | | Merlin (Methane) | 1 | 981 | 311 | 980 |
- | | Nerva (H) | 2 | 246 | 841 | | | + | | Nerva (H) | 2 | 246 | 841 | 250 |
**Total Wet Mass** is equal to the ship **Mass**, plus the mass of fuel times its density. | **Total Wet Mass** is equal to the ship **Mass**, plus the mass of fuel times its density. | ||
+ | |||
+ | ==== Mass ==== | ||
+ | |||
+ | In // | ||
+ | |||
+ | Each // | ||
+ | |||
+ | Some craft are //Weak//, in which case total dry mass (including engines, living quarters, cargo hold etc) is multiplied by 0.75. This also has a negative impact on the hull strength of the ship (base soak x0.50). | ||
+ | |||
+ | Some are // | ||
+ | |||
+ | === Cargo === | ||
+ | |||
+ | The first is cargo space, which when full can contain 10,000kg per // | ||
+ | |||
+ | An empty cargo hold has a mass of 100kg per dT, since it is mostly empty space. When loaded with cargo, the mass of the cargo is in addition to this. | ||
+ | |||
+ | === Fuel === | ||
+ | |||
+ | The second is fuel, which is often a liquid (sometimes solid) which completely fills the fuel tank with no space left over. Like cargo, fuel also has a density and so a full fuel tank increases the mass of the ship. Water counts as +14 per dt (14m³ of water has a mass of 14 tonnes, by definition), | ||
+ | |||
+ | An empty fuel tank has a mass of 100kg per dT, again since it is mostly empty space. | ||
+ | |||
+ | === Supplies === | ||
+ | |||
+ | Crew need supplies, which counts as cargo. 1dt of supplies has a mass of 5,000kg, and will last 1 crew member 1,000 days. This includes food, water, air and other necessities. It is assumed water and air is recycled as much as possible, but ' | ||
+ | |||
+ | === Crew Quarters === | ||
+ | |||
+ | How much space crew need depends on the duration of the flight. | ||
+ | |||
+ | * Hours: ¼dT | ||
+ | * Days: 1dT | ||
+ | * Weeks: 2dT | ||
+ | * Months: 4dT | ||
+ | |||
+ | Cramped quarters are about half this. Luxurious can be from twice to five times this. | ||
+ | |||
scifi/spacecraft.txt · Last modified: 2020/04/26 10:27 by sam