The Murdered Chemist and Modern Spaceflight
How did an 18th-century chemist contribute to the space flight program? This article will walk you through the exciting discoveries of Antoine-Laurent who discovered the secret ingredient for combustion with the help of his wife, Marie-Anne. Little did they know that nearly 200 years in the future, their work would pave the pathway for rockets!
The French Chemist
Antoine-Laurent Lavoisier, pronounced la*vwuh*zei, was born into a wealthy family in 1743. His family encouraged him to get a degree in Law, which he did, but his true passion was for science, and chemistry was his particular love, which at the time, was still considered to be a young science. (Antoine-Laurent Lavoisier 2016)
In order to fund his hobby, Lavoisier bought shares of the Ferme Générale, or General Farm in English, which was a company that collected taxes for the government, but mostly from the poor and with a considerable profit markup. As you can imagine, Ferme Générale was not particularly loved by the French people. (Fermier-général | French finance n.d.) As a part of Ferme Générale, Lavoisier was expected to actively participate in whatever projects were funded by the company at the time. This included his entanglement with the very controversial Wall of Paris, as well as other endeavors such as hypnotism, prison reform, and studying insects. Regardless of these projects, Lavoisier and his wife, Marie-Anne, who was the daughter of one of his employers, still found the time to study four to five hours each weekday. Sundays were this power couple’s self-proclaimed ‘Happy days’, where they could work on their experiments all day. (Bryson, B. 2003)
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Science Discoveries and A Life Cut Short
Lavoisier is known for determining the Law of the Conservation of Mass in chemical reactions, which states that “The total mass of the products of a chemical reaction is always the same as the total mass of the starting materials consumed in the reaction.” (Lavoisier n.d.) He also helped to found the Metric system and pioneered the modern system for naming elements and chemicals. His true scientific calling, however, was to take the discoveries of other scientists and make sense of them; this sometimes included reproving erring scientific theories at the time. One scientist, Jean-Paul Marat, became so offended by a dismissal of his theory of combustion, that he never forgave him and later publicly condemned Lavoisier to be hanged during the French Revolution. Lavoisier’s entanglement with the despised Ferme Générale and involvement with the Wall around Paris, however, is what finally condemned him and in May 1793, he was publicly dispatched at the guillotine. Although Lavoisier’s life was literally cut short, he had a lasting impact on the modernization of chemistry.
Phlogiston and Fire
A prevailing theory in the 18th century was the idea that an unknown material, phlogiston, was the primary substance responsible for combustion. This theory proposed that every object in the universe contained this element responsible for fire. The name was inspired by the Greek word for inflammable. (Antoine Laurent Lavoisier The Chemical Revolution - Landmark n.d.) The reasoning for this theory was based on the observation that objects that have caught fire lose mass. However, several holes were knocked in this theory when Lavoisier discovered was that mass wasn’t lost when something combusted, it simply changed form, disappearing as ash or smoke.
Lavoisier also noted that phosphorus, sulfur, and lead calx all increased in weight as they heated up and combined with the air around them before combusting. In 1777, Lavoisier met up with philosopher Joseph Priestley, who, while still believing in the theory of phlogiston, had discovered that a ‘pure air’ he had collected had caused a candle to burn more fiercely. (Antoine Laurent Lavoisier The Chemical Revolution - Landmark n.d.) Lavoisier used this information and worked with his experiments for a few more years before discovering that the common, breathable air that encouraged combustion was also found in most acids. He appropriately named this substance oxygène, based on the Greek words for acid and generator, and presented his completed theory to the Royal Academy of Sciences in Paris in 1779.
The 18th Century and The Space Race
Thanks to Lavoisier, we know now that the essential ingredient for combustion, oxygen, is not inherently a part of all substances, but needs
to be incorporated with both a fuel to be consumed and some form of heat to do the consuming. This trifecta is known as the combustion pyramid and is pictured in the figure below.
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Fire Triangle Credit: User:Gustavb, CC BY-SA 3.0, via Wikimedia Commons |
Oxygen is integral to combustion because it initiates a chemical process known as Reduction-Oxidation where substances swap electrons. To adapt to the oxygen-less environment of space, spacecraft store fuel and oxidizers as either gasses, liquids, or solids. There are two categories of spacecraft rockets: Liquid rockets and Solid rockets. In the former, fuel and oxidizers are stored separately as liquids until they are pumped into a combustion chamber to spark. In the latter, propellants are already mixed and packed into a solid cylinder. This cylinder will not combust unless introduced to a source of heat. In Solid rockets, the fuel continues to burn until it is all gone; a Liquid rocket, on the other hand, can control thrust by altering the flow of the propellants. These engines are typically more complex to maneuver, and they are far heavier; for these reasons, early spacecraft were all solid-propellent rockets, including the famous Voyager 1.
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| Space Shuttle Credit: NASA; edited by jjron (tilt corrected), Public domain, via Wikimedia Commons |
Wrapping it Up
Lavoisier, a French chemist born in the 18th century, dedicated his life to the pursuit of scientific knowledge and discovery. One of his discoveries, pertaining to the combustion process, strongly opposed the prevailing theory at the time. However, because of his discoveries, we now understand that combustion isn’t an inherent process contained by all elements in the universe! Rather, a special ingredient, oxygen, is needed to set off the spark. Imagine how disappointed NASA would have been if they’d sent a typical combustion-engine rocket into space and expected it to stay running. Thanks to Lavoisier’s discovery, scientists and NASA understood which exact component they needed to include, and modify, in order for Voyager to last all 22 billion kilometers! What are other modern technologies you can think of that have been affected by Lavoisier’s work? Comment your thoughts below!
Sources Cited
“70 Years Ago: First Launch from Cape Canaveral | NASA.” https://www.nasa.gov/feature/70-years-ago-first-launch-from-cape-canaveral/ (April 20, 2021).
“Antoine-Laurent Lavoisier.” 2016. Science History Institute. https://www.sciencehistory.org/historical-profile/antoine-laurent-lavoisier (April 13, 2021).
“Antoine Lavoisier | Biography, Discoveries, & Facts.” Encyclopedia Britannica. https://www.britannica.com/biography/Antoine-Lavoisier (April 13, 2021).
“Antoine Laurent Lavoisier The Chemical Revolution - Landmark.” American Chemical Society. https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/lavoisier.html (April 13, 2021).
Bryson, B. (2003). A short history of nearly everything. New York: Broadway Books.
“Fermier-Général | French Finance.” Encyclopedia Britannica. https://www.britannica.com/topic/fermier-general (April 20, 2021).
“How Do Space Rockets Work Without Air? | Live Science.” https://www.livescience.com/34475-how-do-space-rockets-work-without-air.html (April 13, 2021).
Johnson, Michael. 2019. “Cleaner combustion on Earth, safer combustion in space.” NASA. http://www.nasa.gov/mission_pages/station/research/news/combustion-research-microgravity-clean-burning-fuel-space-station (April 13, 2021).
“Lavoisier.” http://chemed.chem.purdue.edu/genchem/history/lavoisier.html (April 20, 2021).
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