AidSpace Blog

Robert Goddard and the First Liquid-Propellant Rocket

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Ninety years ago today, on March 16, 1926, Robert H. Goddard (1882-1945) launched the world’s first liquid-propellant rocket. His rickety contraption, with its combustion chamber and nozzle on top, burned for 20 seconds before consuming enough liquid oxygen and gasoline to lift itself off the launch rack. The rocket took off from a snowy field outside Worcester, Massachusetts, reaching a height of about 12.5 meters (41 feet) and a distance of 56 meters (184 feet). It was smashed on impact. Goddard, his wife Esther, and a couple of assistants from Clark University, where he was a physics professor, were the only witnesses.

Robert Goddard standing in front of his March 1926 rocket.

Esther Goddard took this picture of her husband with the rocket inside its launch frame on March 8, 1926, in Auburn, Massachusetts. After a failed attempt that day, he successfully launched it on March 16. Image: National Air and Space Museum Archives, NASM 00160386

A replica of Goddard’s liquid-fuel rocket

A replica of Goddard’s liquid-fuel rocket is on display in the Space Hangar at the Steven F. Udvar-Hazy Center in Chantilly, Virginia. Image: Dane Penland, National Air and Space Museum, NASM2016-00687

Goddard’s liquid-fuel rocket from May 1926.

Goddard’s liquid-fuel rocket from May 1926. This rocket borrows parts from his March 1926 rocket and will be on display this spring in our Boeing Milestones of Flight Hall. Image: Dane Penland, National Air and Space Museum, NASM2016-00615

This event did not even make the local newspapers; indeed the reticent professor kept it secret for a decade. He told only a few people and, after a couple of weeks, Charles G. Abbot, the director of the Smithsonian Astrophysical Observatory (and the institution’s Secretary after 1928). The Smithsonian had funded Goddard since 1917, in the hope that his rocket could lift instruments above the atmosphere—the observatory’s main program was measuring solar variability and output.

In January 1920, the Institution had inadvertently made Goddard world-famous when it published his short, often mathematical treatise, A Method of Reaching Extreme Altitudes. A Smithsonian press release, long lost, noted his proposal to hit the night side of the Moon with a rocket carrying flash powder. The story spread quickly around the world—a scientist had legitimized the idea that Moon travel might even be possible. But the press flap also produced a lot of sensationalism. Volunteers wrote to Goddard asking to join the crew of his imminent lunar voyage. Afterward he was not reluctant thereafter to talk to the press in general terms, but he remained secretive about his technical experiments. He was afraid others might steal his inventions, as he was convinced he was the first person in the world to imagine how to make spaceflight feasible. His paranoia only increased after the German space enthusiasts became active in the 1920s.

In 1930, Goddard received greater funding when famed aviator Charles Lindbergh intervened with the Guggenheim foundation. The Clark University professor spent most of the 1930s in Roswell, New Mexico, building and launching much larger rockets. When the Smithsonian, Lindbergh, and Harry Guggenheim pushed Goddard into publishing another report in 1936, he finally revealed the 1926 launch. Yet, as impressive as some of his work in Roswell was, he continued to resist the entreaties of his funders to seek help when his promises to reach the upper atmosphere never materialized. In fact, Goddard’s liquid-propellant rocket work turned out to be close to a dead-end because he was reluctant to share it with anyone. It was the Germans who made the breakthrough to large-scale rocketry with the V-2. Goddard went to his deathbed convinced that the Nazis had stolen their technology from him.

His real importance did not turn out to be inventing liquid-propellant rocketry, although no one can take his first away. He inspired others, however, to believe that space travel would happen if rocketry was developed. Retired National Air and Space Museum curator Frank Winter has shown the global impact of A Method of Reaching Extreme Altitudes. Almost immediately, science-fiction, movies, and non-fiction accounts incorporated the rocket as the fundamental technology for spaceflight. Before 1920, it was only one among many ideas and fantasies. The traditional gunpowder rocket was unimpressive and the laws of physics were widely misunderstood. After Goddard’s publication, and that of other pioneers in Soviet Russia and the German-speaking world, opinion began to change. Robert Goddard thus, almost in spite of himself, paved the way for us to escape the Earth, just as he had long dreamed.

Michael J. Neufeld is a senior curator in the Museum’s Space History Department. His collections include Goddard’s rockets and related equipment.

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Celebrating the Centennial of Coast Guard Aviation with the Seaguard

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Margaret Hamilton

The Museum’s restored HH-52A. Image: John Siemens

Unless you live in a coastal area, or on one of the nation’s waterways, the U.S. Coast Guard is usually out of sight, out of mind, unless something very wrong happens. Unfortunately, this sometimes means that they are overlooked in their significance to our national welfare and security as well as in terms of their own historical legacy and contributions to aerospace. While the National Air and Space Museum has long recognized the importance of the Coast Guard, the Museum has never before had the opportunity or resources to acquire and display an appropriate Coast Guard aircraft. After an 11-year effort, we are finally able to do that, conveniently in conjunction with the Centennial of Coast Guard aviation – celebrating April 1st, 1916, when the Coast Guard’s first aviator, Elmer Stone, reported for flight training with the Navy in Pensacola, Florida.

Our Museum has been a showcase of many milestones of vertical flight, with America’s first successful rotary wing aircraft, the first helicopter accepted for military service, the first turboshaft driven helicopter, and the first truly successful tilt rotor. We also have outstanding examples of operational rotorcraft like the Sikorsky HO5S-1 that rescued hundreds in the Korean War or a Bell UH-1H with 2,500 combat hours in Vietnam, but the non-combat, life-saving role has not been showcased in the Museum before. Now, we have our first Coast Guard aircraft – the Sikorsky HH-52A Seaguard.

Margaret Hamilton

The Coast Guard’s first purpose-built, air-sea rescue aircraft was the Fokker PJ-1 Flying Lifeboat. In smooth waters like this, it could be a very useful tool, but in heavier seas or in situations where a vessel was on fire or someone onboard was severely injured, it could do little. This shortfall in capability led to the Coast Guard’s requirement for air-sea rescue helicopters. Image: NASM 2000-3148

Rescuing people at sea has always been a hazardous undertaking and the idea of being able to pluck someone from a distressed vessel from above goes back to the earliest days of powered flight as this December 1913 Flying editorial about the potential of airplanes to have rescued Titanic survivors illustrates. Between the World Wars, the Coast Guard helped pioneer air-sea rescue with flying boats and amphibian aircraft. However, these airplanes required relatively smooth waters in which to operate and were generally impractical for most open ocean operations, especially when the weather was bad and they were most needed. The advent of the hoist-equipped helicopter during World War allowed this idea to become practical. Unfortunately, through the 1950s, helicopters lacked the range and power to give the Coast Guard the air-sea rescue capability that pioneers like Frank Erickson had sought.

Margaret Hamilton

A 1944 vision of what the Coast Guard wanted in an amphibious rescue helicopter. Image: U.S. Coast Guard

The development of turbine-powered helicopters in the mid-1950s cracked the problems of range and payload for medium-size helicopters. In 1958, Sikorsky Aircraft anticipated the Coast Guard’s long-standing desire for this capability by developing its S-62, an amphibious turbine-powered helicopter that recycled many dynamic components from the S-55, designed in the late 1940s. Ironically, the Coast Guard initially passed in favor of another design, and Sikorsky was forced to market the S-62 for airline service, for which it was not well suited. The Coast Guard eventually came around to the type and ordered 99 of them, which began entering service in 1962 as the HH-52A Seaguard. The Seaguard remained in service until 1989.

Margaret Hamilton

The Museum’s HH-52 spent its retirement years after 1989 at the North Valley Occupation Center, an aviation trade school at the Van Nuys, California airport, where its director, a former HH-52 pilot, looked after it carefully and preserved it largely intact. Twenty-five years of trade school duty nonetheless took its toll on the airframe and it required an exhaustive restoration effort to bring it back to a near operational condition. Image: Roger Connor>

While the Coast Guard’s current fleet of MH-60 and MH-65 helicopters  has eclipsed the Seaguard’s time in service and its achievement of 15,000 lives saved, the HH-52 is still beloved within Coast Guard aviation as the service’s first helicopter that could meet their mission requirements. The aircraft was small enough to deploy aboard cutters, and its amphibious characteristics gave it a degree of safety in over-water operations that was missing in other helicopters. Natural disasters, the emerging war on drugs, and maritime accidents ensured that HH-52 fleet had ample opportunity to demonstrate remarkable feats of heroism.

Margaret Hamilton

1426 had its official post-restoration rollout at the Coast Guard’s Aviation Logistics Center in Elizabeth City, North Carolina on December 11, 2015. Image: >U.S. Coast Guard photo by Petty Officer 2nd Class Nate Littlejohn via DVIDS

Our HH-52A, known by its Coast Guard serial number, 1426, is fully representative of the broad sweep of service provided by the type. It came off the Sikorsky production line in March 1967 and then spent two years in St. Petersburg, Florida, three years in San Juan, Puerto Rico, three years in Detroit, Michigan, three years in North Bend Oregon, and then 10 years in Houston, Texas. In 1989, the helicopter 1426, along with all remaining HH-52s, retired from the Coast Guard. Pilot Stephen Goldhammer ferried the aircraft from Houston to the North Valley Occupation Center. The aircraft remained there until several years ago when the Coast Guard Aviation Association discovered it there while looking for an HH-52 aircraft for restoration that the Coast Guard could then transfer to the National Air and Space Museum. The restoration effort became known as ‘Project Phoenix’ and its installation at the Steven F. Udvar-Hazy Center in coming days will be one of the crowning events in the Coast Guard’s celebration of its centennial of aviation.

Margaret Hamilton

1426 during its deployment aboard a Coast Guard cutter in the Gulf of Mexico during the late 1970s when it was assigned to Coast Guard Air Station Houston. Image: Chris Kilgore

1426 completed its service with 12,619 flight hours. It made particularly significant rescues in 1969 and 1979. In May 1969, it was involved in the rescue of 104 Mormon schoolchildren from a vessel on fire in the Gulf of Mexico near Tarpon Springs, Florida. Its greatest fame came in 1979 when it was a first responder to one of the worst modern maritime disasters in the Gulf of Mexico when the Liberian-flagged tanker Burmah Agate carrying 300,000 barrels of crude oil collided with the Liberian-flagged freighter Mimosa off Galveston, resulting in a massive fire. In three flights, Pilots J.C. Cobb and Chris Kilgore along with Petty Officer Thomas Wynn rescued 22 survivors (another helicopter then rescued an additional five), including the only two survivors from the inferno of the tanker. On the first flight, they rescued 10 from the Mimosa, in addition to the pair from the Burmah Agate. This load of 12 put the helicopter in a dangerous overload from which it barely recovered. More details of this episode may be seen in this Washington Post article.

Margaret Hamilton

Burmah Agate and Mimosa fire off of Galveston, Texas. Image: U.S. Coast Guard

In addition to saving lives, in 1977 while at North Bend, Oregon, 1426 participated in one of the larger narcotics busts up to that time with the seizure of six tons of marijuana on the Panamanian-flagged Cigale off the Oregon coast. The restoration of 1426 was undertaken in Elizabeth City, North Carolina and took about 18 months. It may currently be seen in the Udvar-Hazy Center restoration shop and will soon be suspended in the Boeing Aviation Hangar.


The Museum’s HH-52 seen with the seized bales of marijuana from its participation in the 1977 seizure of the Cigale off the Oregon coast. Image: U.S. Coast Guard


 Roger Connor is a curator in the Aeronautics Department.



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The “Rope Mother” Margaret Hamilton

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Margaret Hamilton

Margaret Hamilton a member of Draper Laboratory staff during the Apollo missions. Image: The Charles Stark Draper Laboratory, Inc, 75579-C

A few years after graduating from Earlham College with a BA in Mathematics, Margaret Hamilton soon found herself in charge of software development and production for the Apollo missions to the Moon at the MIT Instrumentation Laboratory. Her work was critical to the success of the six voyages to the Moon between 1969 and 1972. In a male-dominated field, Hamilton became known as the “Rope Mother,” which was an apt description for her role and referred to the unusual way that computer programs were stored on the Apollo Guidance Computers.

Like all digital computers, they stored information in binary arithmetic—as sequences of ones and zeros. The computer had two kinds of memory. The first could be written to and read from during the machine’s operations—what we now call RAM. The second was read-only—what we now call ROM. Modern memories store these digits on silicon chips, but in the 1960s the preferred way to store digits was by magnetizing tiny, donut-shaped pieces of material called cores. Each Apollo computer contained 4 kilobytes of read-write memory and 72 kilobytes of read-only memory. For the read-only memory, the cores were threaded with a series of wires. If a wire passed through the core it sensed a binary one, and if the wire bypassed the core, a binary zero. The cores were laid out in a long sequence, with the wires snaking through them—the assembly was called a core rope.

Weaving the rope was a tedious process. The programs were developed on a large computer located at the MIT Lab, then translated into a code and punched on to perforated tape. This was then fed into a machine that positioned the cores for proper threading. Most of the employees who threaded the ropes were women, chosen for their manual dexterity. It is not hard to see that getting the programs right was a high priority. Once the ropes were woven it was very difficult and time-consuming to identify and fix an error. It is ironic to call these programs software, since making a change was as difficult, if not harder, than modifying a hardware circuit.

Getting the programs right was the responsibility of Ms. Hamilton, the “Rope Mother.” It was precise work, and it required documenting every decision and every line of code with a full explanation of what it did and how its actions affected the rest of the program. The enormous quantities of paperwork required were typical of the way the entire Apollo program was managed.

In the 1960s there were few formalized guidelines about how to write, document, and test complex software. But the Apollo software worked, and was remarkably error-free. Historians disagree about the cause of the famous computer alarms that nearly caused the Apollo 11 landing to be scrubbed at the last minute. But we do know that the software developed by Hamilton’s group allowed the overloaded Lunar Module computer to restart, shed unimportant tasks, and guide the astronauts to a safe landing. It is worth remembering that today, when we read of computer projects running over budget or being delivered with fatal bugs.

Despite the laborious task, Hamilton and her team kept a sense of humor. She called the women who wove the ropes LOLs or “little old ladies.” Mysterious but minor bugs in the programs were called FLTs or “Funny Little Things.” And you debugged a program by the “Auge Kugel” method. That is the German phrase for eyeball. In other words, you looked at the listing and tried to read it as if you were a computer. Some might not think that was proper engineering practice, but it worked.

A woman weaving the core ropes at the Raytheon plant

Weaving the core ropes at the Raytheon plant in suburban Boston, ca. 1966. Image: From the book  Journey to the Moon: The History of the Apollo Guidance Computer by Eldon C. Hall, Courtesy Raytheon from the files of Jack Poundstone, #CN-4-20-C

Our Museum acquired a number of Hamilton’s papers, including a selection of the program listings shown in the now-famous photograph of her. Recently I had a look at the print-out, which led me to think of another acronym, of obscure origins: MEGO or “My Eyes Glazed Over.” The programmers worked in an obscure, and little-recognized corner of the massive effort that was needed to fulfill President Kennedy’s challenge. I salute them, and give credit to the “Rope Mother” who guided that effort.

One of the many pages that make up Hamilton’s program listings from the Apollo Guidance Computers

One of the many pages that make up Hamilton’s program listings.

Margaret Hamilton stands next to her program documentation for the Apollo Guidance Computer

Margaret Hamilton stands next to the program listings and documentation for the Apollo Guidance Computer. There is a famous statement attributed to Wernher von Braun, although I have been unable to verify it, “When the height of the paperwork is as tall as the Saturn V, it is time to launch.” Whether or not he actually said that, in the case of documenting Apollo software his statement seems apt.

Paul Ceruzzi is a curator in the Space History Department at the National Air and Space Museum.

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How We Saw the Moon: Top Ten Apollo Images

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On February 26, 2016, we opened our latest exhibition of imagery, A New Moon Rises, in our Art Gallery. These stunning images of our largest satellite show, with amazing clarity, our nearest planetary neighbor. But not nearly as clearly as the Apollo astronauts saw it. Here is my top ten list of the most amazing images brought to us by the only 12 people to see the Moon while standing on it. I was not alive for the Moon landings, but these are the images that tell me the story of six missions that changed my world.

Snapshot of Surveyor III

1. Precision

This image speaks volumes for the fulfillment of a goal. That Apollo 12 astronauts Conrad and Bean landed close enough to Surveyor III to take this photo is truly stunning. Image: NASA, AS12-48-7100

Jack Schmitt on the Moon

2. Distance

Astronauts on the Moon were really far from home, expressed with this single image of Jack Schmitt from Apollo 17. Image: NASA, AS17-134-20384

Buzz Aldrin on the Moon

3. Iconic

Landing on the Moon was, to many, the greatest human achievement yet, and this image of Buzz Aldrin from Apollo 11 cemented that idea in public memory. Image: NASA, AS11-40-5903

Broken Lunar Module Fender

4. Engineering

When faced with a broken fender on their rover, Cernan and Schmitt worked with help from 386,243 kilometers (240,000 miles) away to fashion a solution that would keep their travels less messy. Image: NASA, AS17-137-20979

Apollo 16 Telescope

5. Science

Apollo 16 carried the first telescope that operated on another planetary body. The final three Apollo missions in particular were about gathering loads of scientific information for decades worth of research. Image: NASA, AS16-114-18439

Apollo 17 Lunar Rover

6. Challenge

That’s a really big boulder and a really small rover next to it. Look closely and you’ll see the effect of the steep grade on the front right tire of the rover during the Apollo 17 mission. Astronauts explored a very challenging environment. Image: NASA, AS17-140-21493

Jim Irwin Apollo 15 Salute

7. Contrast

Not only is there a striking contrast in colors in this photograph of Jim Irwin from Apollo 15, but the contrast between human, technology, and the lunar landscape is intense. Image: NASA, AS15-88-11866

Lunar Module Lander Leg

8. Force

Landing a lunar module on the Moon wasn’t easy, and this shows the force of impact of just one of the four lander legs on Apollo 14. Image: NASA, AS14-66-9234

Colors on the Moon

9. Color

Colors on the Moon are far more than the gray/silver we see from Earth. Samples and images from Apollo 17 show the diversity of colors on the Moon, including orange, brown, tan, gray-purple, and blue-gray. Image: NASA, AS17-137-20985

Apollo 11 Plaque

10. Legacy

The accomplishments of the Apollo 11 crew and the five crews that landed after them are evidenced by the scientific, engineering, and photographic yield, which are still studied today. What they left behind on the Moon remains a landmark of a unique period in human history.Image: NASA, AS11-40-5899

Jennifer Levasseur is the Museum’s curator for astronaut cameras and personal equipment, and wrote her dissertation on the first 10 years of astronaut photography at NASA.

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Observing the Surface of Venus with the Arecibo Telescope

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This past summer I had the opportunity to operate the world’s largest single-dish telescope at the Arecibo Observatory in Puerto Rico. Before my current position as a postdoctoral researcher at the Museum’s Center for Earth and Planetary Studies (CEPS), I had never operated such a large instrument, much less a 305 meter- (1,000 feet-) wide telescope. During my 10-day observation trip, I used the telescope to take measurements of Venus.

My research at the Museum centers on investigating the radar properties of planetary surfaces using a combination of orbital and telescopic data. For my research on Venus, I have used radar data collected by the Magellan Mission, a spacecraft that orbited Venus in the early 1990s, and the Arecibo Observatory.

Jennifer Whitten in front of the Arecibo Telescope

Me in front of the Arecibo Telescope. Image Courtesy: Jennifer Whitten.

Venus is sometimes referred to as Earth’s twin because the two planets are similar in size, density, and average composition. Many of the same geologic processes are observed on the two planets as well. For instance, Venus has many shield volcanoes, mountain belts, and lava flows like Earth. Here at CEPS we are particularly interested in the distribution of crater ejecta, the material ejected while a crater is being formed. Typically on Venus, crater ejecta are deposited on the surface in parabola (curved) shapes that open to the west. If this material is deposited onto tesserae (highly deformed, radar-bright terrains that represent the oldest surface materials on Venus; see the Arecibo image of Alpha Regio below), it can obscure measurement of the true composition of tesserae. We are working to detect tesserae not contaminated by crater ejecta that could be targeted by future orbital and landed missions to Venus.

Spectacular ejecta surround very young impact crater

Distribution of ejecta (dark material) around an impact crater on Venus in Arecibo radar data. Image from Figure 3 in Campbell et al. [2015].

Before arriving in Puerto Rico, I had seen the Arecibo Telescope in movies (like Contact) and pictures and thought it looked rather impressive, but nothing compared to seeing it in person. The telescope is HUGE, built inside a depression left by a sinkhole. The sinkhole provided a natural location for the telescope and it also helps to shield the telescope from unwanted radio noise that would interfere with measurements.

I fully appreciated the size of the telescope once I was standing above it on the platform that houses all of the instrumentation required to send and receive radio signals. Since the dish is immobile, the suspended platform can be moved to track different objects as they traverse the sky. The instruments are mounted on a linear track, which itself is attached to a circular platform that can rotate 360°, allowing the receiver to move from one side of the dish to the other.

Spectacular ejecta surround very young impact crater

The suspended platform above the telescope dish. This was taken before our observation time. I’m the second dark line from the left on the catwalk (see red arrow). Image Courtesy: Lynn Carter.

Touring the telescope.

Here I am, during our tour of the telescope platform, standing on part of the linear track that holds all of the transmitting and receiving instruments. Image Courtesy: Jennifer Whitten.


The 305 meter-wide dish does not have a smooth surface, but is made up of thousands of aluminum panels that are supported by a mesh of steel cables. Everything has to be tightened by hand. I got to the telescope operations center early on an observation day and was treated to a quick tour underneath the collecting dish. It looks like another world. The vegetation is lush, but it’s pretty shady, and there is a metal ceiling above you. Being directly above or below the dish emphasizes the lattice spacing of the dish panels.

Underneath the collecting dish.

Underneath the collecting dish. Image Courtesy: Jennifer Whitten


View of the platform from underneath the collecting dish.

View of the platform from underneath the collecting dish. Image Courtesy: Jennifer Whitten

We had 10 observation days lined up to measure Venus. We needed all of that time in order to make several repeat observations during our allotted window. Repeat measurements enable us to produce a higher resolution data product. Venus was in inferior conjunction, meaning that the planet was closest to Earth at this time, giving us the highest possible resolution views of the surface. Our telescope time usually started mid-morning and involved warming up and positioning the telescope for observations and ended in the early afternoon after Venus moved outside of the view of the telescope. The observation run was highly successful and I am excited for all of the interesting science that will come out of these measurements!

Spectacular ejecta surround very young impact crater

12.6-centimeter wavelength radar data of the northern hemisphere of Venus collected at the Arecibo Observatory on August 12, 2015. This image was also featured on the @airandspace Twitter account. Image from Smithsonian Institution/NASA GFSC/Arecibo Observatory/NAIC.

Jennifer Whitten is postdoctoral fellow at the Center for Earth and Planetary Studies and uses radar data to study the surface geology of Venus, Mars, and the Moon.

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