CLASSIC PATENTS
Historical Technical Museum
Classic Patents/US 1,155,986
Early Aviation (1900–1910)Aerospace & Rocket Propulsion

Goddard's Multi-Stage Liquid Rocket

US 1,155,986

Multi-Stage Staging and Supersonic de Laval Expansion Nozzles for Extreme Altitudes and Spaceflight

Inventor(s)Robert H. Goddard
Grant Date1915-10-05
Filing Date1913-10-01
LocationWorcester, Massachusetts
Goddard's 1914 staging and nozzle patents: liquid propellant through a de Laval throat, then drop the empty tank. The 1926 Auburn flight lasted 2.5 seconds and 41 feet. The mass-ratio argument is the same one Falcon 9 still uses.
USPTO PDF
Engineering Analysis & Physical Principles

How It Works: Step-by-Step Mechanical & Physical Breakdown

Before Robert Goddard, rockets were simple solid-gunpowder fireworks that could barely reach a mile high because they had to carry heavy burnt-out iron casings the entire way. Goddard proved two critical concepts required to reach space: multi-stage rockets that discard empty deadweight in flight, and supersonic de Laval expansion nozzles that convert hot combustion gases into massive kinetic exhaust thrust.

The Core Breakthrough Mechanism

Propellant burns inside a high-pressure combustion chamber and exhausts through a supersonic hourglass-shaped de Laval nozzle (F=m˙veF = \dot{m} v_e). As lower stages deplete their fuel, mechanical release latches decouple the empty stage, allowing the lighter upper stage to ignite and accelerate to orbital velocity.

Interactive Real-Time 3D Physics Simulation

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Detailed Component Architecture

1Supersonic de Laval Expansion Nozzle

Hourglass-shaped nozzle converting combustion gas thermal enthalpy into supersonic kinetic velocity.

Accelerates gas from subsonic combustion through Mach 1 at the throat to Mach 3+ at the diverging exit cone (ve=2γRT0(γ−1)M[1−(pe/p0)(γ−1)/γ]v_e = \sqrt{\frac{2\gamma R T_0}{(\gamma-1)M} [1 - (p_e/p_0)^{(\gamma-1)/\gamma}]}).

19th-C. Term: Expansion nozzle with tapered throatModern: Supersonic de Laval rocket nozzle
2Multi-Stage Progressive Jettison Mechanism

Automated latches separating depleted fuel stages in flight.

Dramatically improves the mass fraction at each staging event, multiplying final vehicle velocity under the rocket equation (vf=veln⁡(m0/mf)v_f = v_e \ln(m_0 / m_f)).

19th-C. Term: Detachable cartridge sectionsModern: Multi-stage launch vehicle staging
3High-Pressure Liquid Combustion Chamber

Combustion chamber engineered for continuous propellant burning.

Handles intense combustion pressures and thermal loads without detonating.

19th-C. Term: Combustion chamber with propellant feedModern: Regeneratively cooled rocket combustion chamber

Governing Physical Equations & Principles

Tsiolkovsky Rocket Equation & Multi-Stage Mass Ratio
Δv=ve⋅ln⁡(m0mf)=Ispg0⋅ln⁡(m0mf)\Delta v = v_e \cdot \ln\left(\frac{m_0}{m_f}\right) = I_{sp} g_0 \cdot \ln\left(\frac{m_0}{m_f}\right)
Jettisoning empty structural mass at each stage allows the upper stages to achieve terminal velocities exceeding Earth escape velocity (11.2 km/s).
Supersonic Compressible Flow & Nozzle Expansion
AA∗=1M[2+(γ−1)M2γ+1]γ+12(γ−1)\frac{A}{A^*} = \frac{1}{M}\left[\frac{2 + (\gamma-1)M^2}{\gamma+1}\right]^{\frac{\gamma+1}{2(\gamma-1)}}
The converging-diverging geometry expands high-pressure exhaust gas into the vacuum of space, maximizing thrust and specific impulse.

Why It Still Matters

Falcon 9 still throws away (or now lands) a stage so the upper stage is not hauling empty tanks. That is Goddard's 1914 mass-fraction claim with better metallurgy.

Legal Claims Decoder (1 Numbered Claims)

Compare dense legalistic claims directly with decoded plain-English functional specifications.
Claim #1Independent Master Claim
Verbatim Historical Legal Text
“In a rocket apparatus, a plurality of combustion chambers, each chamber having an expansion nozzle, and means for successively igniting the charges in said chambers and separating the spent chambers from the apparatus.”
Plain English Engineering Translation
The master claim covering a multi-stage rocket with multiple combustion chambers, expansion nozzles, and a mechanism to successively ignite charges and detach spent chambers.
Key Protected Innovations:
Multi-stage rocket architectureSupersonic expansion nozzlesIn-flight detachment of empty propellant stages
Historical Legal Impact:

The foundational patent of modern astronautics and space launch vehicle staging.

The Historical Bottleneck

A Congreve stick-rocket is a gunpowder case you throw away all at once. Tsiolkovsky (1903) already had $\Delta v = v_e \ln(m_0/m_f)$. Nobody in America had a pump, a regenerative chamber, and a nozzle that would not melt, in one vehicle.

Why Prior Art Failed

  • •Black-powder artillery rockets, low $v_e$, no throttle.
  • •Tsiolkovsky and Oberth on paper.
  • •Single-stage mass ratios that could not reach orbit even in theory.
The Breakthrough Insight

“Goddard's 1914 patents split the problem: liquid propellants through a de Laval nozzle (high $v_e$), and staging so you stop carrying empty tankage. The 1926 Auburn flight was gasoline and liquid oxygen, 2.5 seconds, 41 feet. Ugly. First.”

Patent Wars & Legal Litigations

Vs. The New York Times editorial page (1920)Infringement Challenge
Rival Claim & Defense:

A rocket cannot work in vacuum because there is nothing to push against. Goddard, Clark University, 'does not know the relation of action to reaction.'

Litigation Conflict:

Goddard had already run motors in a vacuum tank. Thrust rises as $p_a$ falls: $F = \dot{m}v_e + (p_e-p_a)A_e$. On 17 July 1969 the Times printed a retraction while Apollo 11 was on the way to the Moon.

Final Resolution & Judicial Outcome:

The US government settled Goddard's estate in 1960 for $1 million, covering a stack of patents NASA and the Army had been using.

After the Grant

Lindbergh got Guggenheim money to move Goddard to Roswell. The Army mostly ignored him until the V-2s arrived. He died in 1945, just as the German files proved he had been right about almost every subsystem.

Civilizational Impact

Von Braun read Goddard. So did the GALCIT group that became JPL. Staging and liquid oxygen are still how a first stage leaves Florida.

Historical Fact

The 16 March 1926 stand was a pipe frame in an Aunt Effie farm field. The rocket went up, sideways, and into the cabbage. Esther Goddard ran the camera.

Further Context
  • US 1,102,653 is the rocket apparatus; US 1,155,986 is the multi-stage claim. The museum treats them as one story because Goddard did.
  • He was secretive to a fault. American rocketry duplicated some of his work because he would not publish drawings.