🌍 Orbital Heat Flux Calculator

Solar constant · albedo flux · Earth IR · altitude-dependent view factor · hot/cold cases

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Inputs

Results

Direct solar flux
– W/m²
Earth view factor (nadir plate)
–
Earth IR flux on nadir plate
– W/m²
Peak albedo flux (subsolar)
– W/m²
Earth angular radius
– deg
Space sink temperature
3 K
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📖 How to use

  1. Enter the altitude and pick the solar constant case — use the hot case (perihelion, high albedo/IR) and cold case (aphelion, low albedo/IR, eclipse) as bounding environments.输入高度并选择太阳常数工况——热工况（近日点、高反照/红外）与冷工况（远日点、低反照/红外、地影）作为包络环境。
  2. The view factor scales Earth IR and albedo for a nadir-facing flat plate; other orientations see less.视角系数是对地平板的取值，用于折算地球红外与反照；其他朝向取值更小。
  3. Feed these fluxes into Spacecraft Heat Balance and Radiator Sizing; get eclipse durations from OrbitTools' Beta Angle & Eclipse tool.把这些热流填入整星热平衡与散热面设计工具；地影时长用 OrbitTools 的 β 角与阴影工具计算。
  4. Albedo flux applies only on the sunlit side of the orbit and depends strongly on the sun-surface geometry — the value here is the subsolar worst case.反照热流只在轨道光照段存在，且强烈依赖太阳-表面几何——此处给出的是星下点最恶劣值。

The three external heat sources

Direct solar: S = 1361 ± 3.4% W/m² over the year (Earth orbit eccentricity). Applies to sun-facing surfaces as α·S·cos θ.

Albedo: sunlight reflected by the Earth, q_alb = a·S·F with a ≈ 0.30 ± 0.05. Worst at the subsolar point, zero in eclipse.

Earth IR: the Earth radiates ≈ 237 W/m² (equivalent blackbody 255 K); a nadir plate receives E·F where the view factor for a flat plate is F = (R_E/(R_E+h))².

Deep space is a ≈ 3 K sink — effectively zero return flux. These four numbers (S, a, E, F) define the classic hot/cold bounding cases used in early thermal design.

All computation runs locally in your browser.

三大外部热源

太阳直射: S = 1361 ± 3.4% W/m²（随地球轨道偏心率年变化）。对受晒表面按 α·S·cos θ 吸收。

地球反照: 地球反射的阳光，q_alb = a·S·F，a ≈ 0.30 ± 0.05。星下点附近最大，地影中为零。

地球红外: 地球自身辐射约 237 W/m²（等效黑体 255 K）；对地平板接收 E·F，平板视角系数 F = (R_E/(R_E+h))²。

深空是约 3 K 的热沉——回流可视为零。S、a、E、F 四个数即构成方案阶段经典的热/冷包络工况。

全部计算在你的浏览器本地完成。