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Volume VIII · 00 · The stack · 層次

Volume VIII · Rockets火箭

Mass ratio, a jet of gas, and 9.4 km/s of bill to LEO.

A rocket is a mass ratio and a jet of gas. Staging, engines, gravity losses, then the heat of coming home. LEO is 9.4 km/s of bill, not 7.8 of poetry.

Start with delta-vSkip to staging

In English

Getting to space is a budget in km/s, not a vibe. This volume is the rocket equation, why we stage, what engines trade, the losses that turn 7.8 into 9.4, and the heat of coming home.

Try this
Start at Delta-v. Skip to Staging if you already believe the log.
Keep this
LEO is ~9.4 km/s of Δv. Staging exists because of a logarithm.

The stack · click a layer

  1. 06Heat熱
  2. 05Ascent上升
  3. 04Losses損耗
  4. 03Engines引擎
  5. 02Staging分級
  6. 01Delta-v速度增量

What this is

A mass-ratio slider, stages you can drop, engines that trade Isp for T/W, a gravity-loss bill, an eastward launch, and a blunt shield.

What this is not

Not a GNC sim and not a particular vehicle. The 9.4 km/s LEO budget, the rocket equation, and staging as a logarithm are the real claims.

  1. 01 · The equationDelta-v速度增量Slide mass ratio and Isp. Watch Δv.$\Delta v = v_e \ln(m_0/m_f)$. Tanks buy less than they appear to.
  2. 02 · The equationStaging分級One fat stage versus drop the tank.Staging is the rocket equation applied twice. SSTO is stubborn.
  3. 03 · The jetEngines引擎Pick an engine. See Isp versus T/W.First stage is T/W. Coasting between planets is Isp.
  4. 04 · The billLosses損耗Raise T/W. Gravity loss falls.The budget is 9.4, not 7.8. High T/W spends less time hanging.
  5. 05 · The billAscent上升Pick a pad. Aim east or north.Inclination ≥ latitude unless you pay. East is a coupon.
  6. 06 · Coming homeHeat熱Speed up. Blunt versus sharp.Blunt bodies survive. Heating scales roughly with $v^3$.