“That’s one small step for man, one giant leap for mankind.”

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Source: NASA

When Neil Armstrong (right) took the first human steps on another planet on 20th July 1969 and spoke those famous words, he not only achieved a goal set by US President John F. Kennedy but fulfilled a dream as old as humanity.

President Kennedy had stood before congress in 1961 and proposed that the US “should commit itself to achieving the goal, before the decade is out, of landing a man on the Moon and returning him safely to the Earth.” The Apollo 11 mission successfully completed this goal eight years later and wrapped up a huge victory for the US over the Soviets in the Cold War space race.

NASA’s Apollo programme ran from 1961 to 1975 and resulted in 11 spaceflights and 12 American astronauts walking on the Moon. The first four flights tested the equipment and six of the other seven flights landed on the Moon. This July marks 50 years since Armstrong, Edwin ‘Buzz’ Aldrin and Michael Collins became the first human beings to leave Earth’s orbit and step foot on another world – a mission which would not have been possible without industrial gases.

“Oxygen, hydrogen, nitrogen and helium: these gases, and their liquefied forms of storage and handling, are the driver for the entire space enterprise. It’s not possible without them,” James Fesmire, Senior Principal Investigator and founder of the Cryogenics Test Laboratory at NASA Kennedy Space Center, tells gasworld in an exclusive interview to mark the 50th anniversary of the first Moon landing. “The centrepiece of any launch vehicle is chemical-based stored energy, it fundamentally is. Any rocket is basically a big flying set of tanks. with engines at the bottom.”

The Saturn V was the ‘big flying tank’ that took Armstrong, Aldrin and Collins to the Moon. Measuring 111 metres tall, it was about the height of a 36-story-tall building and 18 metres taller than the Statue of Liberty.

Fully fuelled for lift-off, the Saturn V weighed 2.8 million kg (the weight of about 400 elephants) and generated 7.5 million pounds of thrust at launch, creating more power than 85 Hoover Dams. To put that into perspective, a car that gets 48km to the gallon could drive around the world around 800 times with the amount of fuel the Saturn V used for a lunar landing mission.

The rocket used for the Apollo missions had three stages and each stage would burn its engines until it was out of fuel. It would then separate from the rocket. The engines on the next stage would fire and the rocket would continue into space.

The first stage had the most powerful engines since it had the challenging task of lifting the fully fuelled rocket off the ground. It carried 203,000 gallons of kerosene fuel and 318,000 gallons of liquid oxygen needed for combustion, and lifted the rocket to an altitude of about 68km. The F-1 engines then shut down, explosive bolts fired, and the severed first stage fell into the ocean.

“The first stage of the Saturn V had five F-1 rocket engines at the bottom and the amount of liquid mass that came out of them every second was about 30,000 pounds, which is equivalent to about nine Toyota Camrys – every second, nine Toyota Camrys worth of mass came out of the bottom of the rocket. The power of that thing was unbelievable,” explains Adam Swanger, Research Engineer at the Cryogenics Test Laboratory.

The second stage used 260,000 gallons of liquid hydrogen fuel and 80,000 gallons of liquid oxygen to carry the rocket almost into orbit. At nine minutes and nine seconds after launch, the second stage was discarded and the third stage’s rocket engine was fired. The third stage placed the Apollo spacecraft into Earth’s orbit and pushed it towards the Moon, using 66,770 gallons of liquid hydrogen fuel and 19,359 gallons of liquid oxygen to do this. The last remaining part of the rocket stayed in space, or hit the Moon.

“Liquefied gases were central to the Moon missions. To me, a kind of equivalent question would be: how important is uranium, or some other radioactive material, to a nuclear reactor or a nuclear power plant? Without it, there is no reason for it to exist or it cannot exist. Without liquid oxygen you don’t have human space flight,” says Swanger.

This is without even mentioning the helium, argon and carbon dioxide (CO2) used in welding the various rocket components together, or the liquid nitrogen that would have been used in testing components under extreme cold conditions along the journey to launch.

Man-on-the-moon

Mission highlights

Apollo 11 launched from Cape Kennedy on 16th July 1969 at 9.32am EDT, carrying Armstrong (Commander, pictured left), Collins (Command Module Pilot) and Aldrin (Lunar Module Pilot) strapped side by side inside the Columbia Command Service Module. At around 12.22pm EDT, after an orbit and a half around the Earth, engines from the third-stage of the Saturn V rocket ignited for a crucial burn and lifted Columbia out of Earth orbit and on towards the Moon, explains the National Space Centre.

After three days of travelling towards the Moon, Columbia flipped around and fired its rocket backwards for six minutes so that it slowed the spacecraft down enough to be captured by the Moon’s gravity. This key burn happened behind the Moon, outside of radio contact with Mission Control. If the burn was too short, Apollo 11 would have slingshot around the Moon and headed back to Earth; if the burn was too long, the spacecraft would have risked crashing into the Moon. Columbia settled on an orbit that was just 70 miles above the Moon’s surface.

Moonwalkers Armstrong and Aldrin entered the ‘Eagle’ Lunar Lander on 20th July 1969 at 13.26pm EDT and separated from Collins, who remained in Columbia in orbit around the Moon. The Eagle descended towards the Moon and scanned the surface for a suitable landing site.

Armstrong struggled to find a smooth place to land in a boulder-strewn field. At the last minute, he found a site and landed with 25 seconds of fuel to spare, at 16.18pm EDT. He immediately radioed Mission Control with those immortal words, “Houston, Tranquillity Base here. The Eagle has landed.” Upon landing, Aldrin described the Moon’s surface as “pretty much without colour. It’s grey and it’s a very white chalky grey.”

Armstrong and Aldrin found it impossible to sleep and instead prepared for their lunar walk more than five hours ahead of schedule. After donning his bulky Extravehicular Mobility Unit (EMU) spacesuit, Armstrong slowly squeezed through the tight Lunar Module hatch and down the nine-step ladder.

With an estimated 650 million people watching Armstrong’s televised image, he placed his left foot on the Moon at 22.56pm EDT. It was the first time in history that man had ever stepped on anything that had not existed on or originated from the Earth. Aldrin followed around 15 minutes later and became the second man to walk on the Moon.

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Source: NASA

The two astronauts erected a three-by-five-foot nylon US flag at 23.41pm EDT. They also left commemorative medallions bearing the names of the three Apollo 1 astronauts who lost their lives in a launchpad fire and two cosmonauts who also died in accidents on the Moon’s surface. A one-and-a-half inch silicon disk, containing micro-miniaturised goodwill messages from 73 countries, and the names of congressional and NASA leaders, also stayed behind.

US President Richard Nixon called the astronauts by telephone at 23.48pm EDT. He said the call had to be the “most historic telephone call ever made.”

Over the next hour and a half, Armstrong and Aldrin collected 21.55kg of lunar rock and set up two science experiments which were left on the Moon: a seismic detector and a laser reflector. The latter is still in use today to measure the distance between the Earth and the Moon.

Aldrin and Armstrong spent 21 hours and 36 minutes on the Moon’s surface. They were reunited with Collins at 17.35pm EDT on 21st July 1969, when the Eagle docked with Columbia while circling on the back side of the Moon. While on the back side of the Moon, Columbia made the crucial burn that lifted the crew from Moon orbit and on towards a return trajectory to Earth.

After three days of travel, Columbia re-entered Earth’s atmosphere at 12.35pm EDT on 24th July 1969. It splashed down into the Pacific Ocean around 20 minutes later and was quickly picked up by the recovery team. When the three astronauts emerged from their spacecraft they were sprayed with disinfectant as a guard against potential ‘Moon germs’.

From then to now

Fesmire joined NASA aged 18 in 1983, 11 years after the last Apollo mission, when things in cryogenics were still being done very much the same as they were in the ‘60s and ‘70s – from scratch.

“Back then, most things in cryogenic systems were designed and built from scratch. Things weren’t available on the street to just go and buy. We had to get out a pencil and from scratch draw, say, a vacuum-jacketed piping assembly and then go procure it from someone who had to custom make it. That’s a huge difference to today, when it’s much simpler,” he explains.

“As for the application of the different gases back then and how they were used, a lot of it in my view is really still the same. A lot of the processes and operations are still being used today,” adds Swanger.

“There are new materials we use today so things can be a lighter weight and more economical to fabricate in the welding process.”

Swanger said the newest and most recent advancement that is being used now is the densification of the propellants related to liquid oxygen or liquid hydrogen fuels. “Densification refers to the process of cooling the liquid propellant below its normal boiling point, with the intention of increasing its density. This is what Space X has been doing on their rocket and that’s how they actually enable them to get their boosters back, which I’m sure everybody has seen. It’s been pretty impressive in the last couple of years.”

Fesmire and Swanger both agree the space industry is just at the beginning of new advancements and NASA has made contributions particularly in materials and processes, instrumentation and sensors, thermal insulation systems, and the integrated refrigeration and storage of liquefied gases. The space agency is currently building the world’s largest liquid hydrogen storage tank at the Kennedy Space Center. “During the Apollo programme in the ‘60s and ‘70s, and then the 30-year Space Shuttle programme that followed, these missions were very specific and short-term and there was no way to keep liquefied gases for a long period of time,” Fesmire explains.

“Prior to being loaded into the launch vehicle, the liquid hydrogen and liquid oxygen was stored in 850,000 gallon spherical containers – each about 1,500 feet from the pad. This technology was developed during the early stages of World War II. The tanks were made of stainless steel.”

“The ongoing problem during the Apollo and Space Shuttle era was significant boil-off or evaporation and the operational limitations. While liquid hydrogen and liquid oxygen are excellent, high-performance rocket propellants, they are cryogenic. The oxygen in a liquid state is -297ºF (-183ºC) and hydrogen is -423ºF (-253ºC). Because of the heat from the ambient temperatures, storing these commodities is like storing ice in an oven.”

“The existing liquid hydrogen storage tanks were vacuum-jacketed with four-feet-thick perlite insulation. They were state-of-the-art in 1965, but boil-off was an ongoing problem and substantial losses were unavoidable. We felt like there had to be a better way,” adds Swanger.

Integrated Refrigeration and Storage (IRaS) is a refrigeration system allowing control of the fluid inside the storage tanks. This approach provides direct removal of heat energy using an integrated heat exchanger together with a cryogenic refrigeration system. The new technology also is being coupled with new ‘glass bubble’ insulation to replace perlite powder. Based on various field demonstration tests completed at Kennedy and NASA’s Stennis Space Center in Mississippi, with glass bubble insulation, liquid hydrogen losses through boil-off can be reduced by as much as 46%. This will be especially important for the new liquid hydrogen tank that will hold 1.25 million gallons of liquid.

“Comparatively speaking, it’s like going from storing ice in a picnic cooler for a few hours to keeping it indefinitely in a freezer. While insulation in a picnic cooler will slow melting, it won’t stop it and there is no control. Similarly, cryogenic liquids evaporate when stored in an insulated container, even one with the highest performance vacuum-jacketed insulation system,” explains Fesmire.

Next giant leap

Apollo 11’s historic mission to the lunar surface 50 years ago blazed a new trail for human exploration beyond our home planet. Now, NASA is looking at the next giant leap – sending humans back to the Moon and then on to Mars.

Getting man to Mars

US President Donald J. Trump refocused America’s space programme on human exploration and discovery back in December 2017. He said, “It marks a first step in returning American astronauts to the Moon for the first time since 1972, for long-term exploration and use. This time, we will not only plant our flag and leave our footprints – we will establish a foundation for an eventual mission to Mars, and perhaps someday, worlds beyond.”

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Source: NASA