# rocket

Rocket propellant stats of a fluid.

Place the object under `traits` in a fluid-property file. Rocket and station engines, orbital-station docking and the Rocket Transporter Pad read it; the transporter cannot send without a propellant carrying it. The LPW-3N Station Thruster accepts a heated product only when that product has this trait. An engine whose propellant lacks it uses ISP 300; station docking then uses thrust 600,000.

## Fields

| Field | Meaning and default | Range |
| - | - | - |
| `isp` | Specific impulse; exhaust velocity is $9.81 \times$ ISP, which sets propellant cost. | `i32` |
| `thrust` | Thrust in newtons, used for lift-off and landing delta-v; read as a 32-bit integer. | `i64` |

## Example

From `data/hbmspace/fluid_property/hydrazine.json`:

```json
{"rocket": {"isp": 210, "thrust": 600000}}
```