On March 16, 2026, liquid-fueled rocketry turns 100 years old. The same fundamental propulsion concept that Robert Goddard proved viable in a Massachusetts field in 1926, burning liquid fuel against liquid oxidizer to generate thrust, still sits at the heart of NASA’s most powerful active rocket. The Space Launch System that carries the Artemis program toward the Moon runs on four RS-25 engines fed by liquid hydrogen and liquid oxygen, a direct descendant of the technology Goddard pioneered a full century ago.
A 2.5-Second Flight That Defined a Century
Goddard, a U.S. professor of physics working in Auburn, Massachusetts, launched the world’s first liquid-fueled rocket on March 16, 1926. The device used gasoline as fuel and liquid oxygen as its oxidizer, according to NASA’s early account. The flight lasted roughly 2.5 seconds. It was short, unstable, and by any modern standard, primitive. But it demonstrated something no prior experiment had: that a liquid-propellant engine could produce controlled thrust in open air.
NASA’s historians have revisited that test multiple times, emphasizing how small details (a snowy farm, a spindly frame of pipes and tanks, and a modest burst of flame) marked the beginning of modern astronautics. A later historical summary notes that the rocket rose only about 41 feet and landed in a cabbage field, yet it proved that liquid propellants could be fed, ignited, and sustained long enough to generate meaningful thrust. That proof of concept was what mattered: if such a fragile rig could fly at all, more powerful and reliable versions were clearly within reach.
Over the decades, NASA has explicitly tied its current exploration efforts back to that moment. In a centennial reflection, the agency described how Goddard’s experiment in a cabbage patch evolved into a lineage of engines that now send spacecraft to lunar craters and beyond, underscoring that the Artemis program is built on one century of modern rocketry. The V-2, the Saturn V, the Space Shuttle Main Engine, and SLS all follow the same basic recipe: combine a liquid fuel with a liquid oxidizer in a combustion chamber, accelerate the exhaust through a nozzle, and ride the resulting thrust to the edge of space.
NASA has also used anniversaries of Goddard’s launch to remind the public how radical his ideas once seemed. In marking an earlier milestone, the agency pointed out that the 1926 flight laid the groundwork for everything from communications satellites to planetary probes, linking a few seconds of flight in Massachusetts to a sprawling solar system of missions. The basic physics did not change; engineers simply learned how to harness it on ever larger scales.
The RS-25: Shuttle-Era Hardware for a Lunar Return
The four RS-25 engines bolted to the bottom of the SLS core stage are not new designs. They are evolved versions of the Space Shuttle Main Engine, an engine family that first flew in 1981. For SLS Block 1, the configuration used on Artemis I and planned for Artemis II and III, NASA chose to keep these liquid hydrogen engines rather than develop an entirely new powerplant. The logic was straightforward: the RS-25 had decades of flight heritage, a well-understood failure profile, and existing manufacturing infrastructure.
Technically, the RS-25 is a staged-combustion engine, meaning it partially burns propellant in a preburner to drive turbopumps before routing the hot gas into the main combustion chamber. This allows high chamber pressures and high efficiency, a key reason the engine was prized during the Shuttle era. For SLS, the engines are operated at even higher power levels than before, taking advantage of design margins built into the original hardware.
That decision carries a real tradeoff. Heritage engines reduce development risk, but they also anchor the program to production lines, supply chains, and design assumptions rooted in 1970s-era engineering. Each RS-25 is expended after a single SLS flight, unlike the Shuttle era when the engines were recovered and reused. This shift from reusable to expendable use for an engine originally designed for reuse raises a question that NASA’s own procurement decisions reflect: how do you affordably produce enough of these engines to sustain a long-duration lunar campaign?
Restarting a Production Line for Deep Space
NASA’s answer has been to invest in modernized manufacturing. The agency selected Aerojet Rocketdyne to restart production of RS-25 engines with specific modernization goals: fewer parts, fewer welds, and certification at higher thrust levels. The intent is to bring down per-unit cost while squeezing more performance from each engine. Reducing welds, for example, cuts both manufacturing time and potential failure points in the combustion chamber and nozzle assemblies.
Modern fabrication techniques, including advanced machining and additive manufacturing for certain components, allow engineers to simplify what was once an intricate maze of pipes and joints. While the core thermodynamic cycle remains the same, the way the engine is built is changing to reflect half a century of progress in materials science and industrial automation.
NASA has also committed to procuring additional RS-25 engines beyond the initial inventory, a signal that the agency views SLS as its deep-space workhorse for multiple Artemis missions. The agency’s decision to order more engines locks in liquid-fueled propulsion as the backbone of the program for years to come. That commitment means Artemis is not hedging toward alternative propulsion architectures for its core launch vehicle anytime soon; instead, it is doubling down on an approach that has been refined over decades.
Proven Boosters, Familiar Chemistry
The RS-25 engines do not work alone. SLS also uses enhanced solid rocket boosters for its initial flights, hardware derived from the Shuttle’s solid rocket boosters, according to an SLS fact sheet from the Lunar and Planetary Institute. The combination of solid boosters for initial liftoff thrust and liquid-fueled core engines for sustained, throttleable power during ascent is itself a decades-old architecture. NASA describes the SLS as relying on proven booster hardware, a phrase that captures both the program’s strength and its conservatism.
For a general reader, the practical consequence is this: the rocket carrying astronauts back to the Moon does not represent a clean-sheet engineering leap. It represents careful, incremental refinement of systems whose fundamental chemistry (liquid oxygen reacting with a liquid fuel inside a high-pressure chamber) has not changed in principle since Goddard’s 1926 flight. The fuels have improved (liquid hydrogen replaced gasoline), the materials are vastly better, and the control systems are digital rather than mechanical, but the underlying idea is identical.
NASA’s own storytelling underscores that continuity. The agency’s centennial reflections on Goddard’s work highlight how a backyard experiment evolved into a national infrastructure for spaceflight, from small sounding rockets to the towering SLS. The through line is liquid propulsion: tanks, pumps, valves, and engines designed to tame a controlled explosion and bend it into useful work.
A Century of Liquid Fire
As March 16, 2026, approaches, the contrast between Goddard’s fragile rig and the SLS stack on a modern launch pad is striking. One was assembled on a farm; the other is integrated in high bays and rolled to the pad on a crawler-transporter. Yet at ignition, both rely on the same sequence: chill the plumbing, flow propellants, spark the mixture, and let high-velocity exhaust push against the Earth.
If Artemis succeeds in establishing a sustained human presence around and on the Moon, it will do so on the back of that century-old insight. Future architectures may eventually lean more heavily on nuclear thermal propulsion or high-power electric thrusters for deep-space travel, but getting heavy payloads off Earth still favors the brute force of chemical rockets. For now, the path from cabbage fields to lunar craters runs straight through liquid-fueled engines.
One hundred years after Goddard’s 2.5-second hop, every SLS launch is, in a sense, a reenactment at vastly larger scale. The hardware is different, the stakes are higher, and the destinations are farther away. The principle (burning liquid propellants to climb out of a gravity well) remains the same, a reminder that some ideas are powerful enough to define an entire century of exploration.
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*This article was researched with the help of AI, with human editors creating the final content.
