⚖️ Propellant Mass Calculator

📖 How to use

1. Bring the margined Δv from the Δv Budget tool and pick the propellant type — Isp auto-fills.带入 Δv 预算工具的含余量 Δv，选推进剂类型——Isp 自动填入。
2. Choose whether you know the dry mass (bottom-up build) or the wet mass (launcher-limited) — the tool solves the other.选择已知干重（自下而上估算）还是湿重（受运载约束）——工具反解另一个。
3. Note the Isp leverage: the same 176 m/s costs a 200-kg sat ~15 kg of hydrazine but only ~2 kg of xenon on a Hall thruster.注意 Isp 的杠杆：同样 176 m/s，200 kg 卫星用肼约需 15 kg，用霍尔电推只需约 2 kg 氙。
4. Continue to Tank Sizing for volume and to Mass Budget to roll the propellant into the wet mass.接着用贮箱容积算体积，用质量预算把推进剂并入湿重。