🏗️ Satellite Mass Budget Calculator

Payload → dry mass via SMAD fractions · subsystem allocation · margin · wet mass & launch check

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Sizing Inputs

Subsystem Allocation (% of dry)

Editable SMAD-style fractions. They need not sum exactly to 100 − payload%; the table shows the implied kg and the residual.

SMAD 式分配比例，可编辑。各项不必恰好凑成 100 − 载荷%；表格给出折算 kg 与残差。

Subsystem%kg

Results

Dry mass estimate
– kg
Dry with margin
– kg
Wet (launch) mass
– kg
Allocation residual
– %
Launch margin
– kg
–
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📖 How to use

  1. Enter the payload mass and a payload fraction (SMAD: 25–32% of dry for most sat classes) — dry mass = payload/fraction.输入载荷质量与载荷占比（SMAD：多数卫星为干重的 25–32%）——干重 = 载荷/占比。
  2. Tune the subsystem percentages to your architecture (EP missions push power up; imaging pushes structure/ADCS up); watch the residual.按构型微调分系统百分比（电推任务电源占比高；成像任务结构/姿控占比高），注意残差。
  3. Add system margin (mass only grows) and the propellant from the Propellant tool to get the wet mass; check it against the launcher.加上系统余量（质量只会涨）与推进剂工具的推进剂得到湿重；对照运载能力校核。
  4. Iterate: wet mass changes the Δv propellant, which changes wet mass — one or two loops converge.注意迭代：湿重变化影响推进剂量，推进剂又改变湿重——通常一两轮即收敛。

SMAD mass estimating

At concept stage, spacecraft dry mass is estimated top-down from the payload: m_dry = m_payload / f_payload, then allocated across subsystems by historical fractions (structure ~20%, power ~19%, ADCS ~8%, thermal ~3%, TT&C+C&DH ~7%, propulsion dry ~6%, harness ~7%).

Carry 15–25% system margin early: payloads gain mass, harness always weighs more than drawn, and structure follows both. The budget converges bottom-up as real equipment replaces fractions.

All computation runs locally in your browser.

SMAD 质量估算

方案阶段整星干重自上而下由载荷推得：m_干 = m_载荷 / f_载荷，再按历史统计比例分配到各分系统（结构约 20%、电源约 19%、姿控约 8%、热控约 3%、测控+数管约 7%、推进干重约 6%、电缆网约 7%）。

初期保留 15–25% 系统余量：载荷会长胖、电缆永远比图纸重、结构随之增长。随着真实单机替换比例，预算逐步转为自下而上收敛。

全部计算在你的浏览器本地完成。