How Does a Spacecraft Come Back to Earth Without Burning Up?

Artemis II rocket

With Artemis II drawing more attention to the Orion spacecraft, I thought one of the most interesting questions was: How can a spacecraft return to Earth at such high speed without burning up? When Orion comes back from a mission around the Moon, NASA says it reenters Earth’s atmosphere at about 25,000 mph and faces temperatures of nearly 5,000°F. That is hot enough that protecting the astronauts is not just an engineering problem but also a chemistry and materials science problem.

The key idea is the heat shield, which for Orion is made primarily from a material called Avcoat. NASA explains that Avcoat is an ablative material. That means it is designed to slowly break down, char, and wear away in a controlled way during reentry, rather than simply trying to resist the heat forever. In other words, the spacecraft survives because part of the heat shield is intentionally sacrificed. As the material heats up, physical and chemical changes in the shield help carry heat away from the capsule rather than letting that heat pass directly inside.

 

Avcoat 

This is where the chemistry becomes really important. During reentry, the air in front of the spacecraft is compressed so intensely that it becomes extremely hot. The heat shield then undergoes thermal decomposition and ablation, meaning chemical bonds in the material break, gases are produced, and the outer layer chars and erodes. NASA describes this process as a controlled burn-off that transports heat away from Orion. So the shield is not just a passive barrier; it actively uses chemistry to protect the spacecraft.

What makes this even more interesting is that NASA learned from Artemis I that the chemistry and gas flow inside the ablative material have to be managed very carefully. In its 2024 update, NASA said gases generated inside Orion’s Avcoat during reentry did not vent and dissipate as expected in some areas, which caused pressure to build up and led to cracking and loss of some charred material. That shows how small details in material chemistry can become mission-critical when a spacecraft is returning from the Moon.

I think this topic is so interesting because people usually imagine space travel as mostly rockets and engines, but the return to Earth depends just as much on chemical reactions, heat transfer, decomposition, and material design. A spacecraft survives reentry not by avoiding extreme heat, but by using smart chemistry to manage it. 

Source: https://www.nasa.gov/humans-in-space/after-15-years-1000-tests-orions-heat-shield-ready-to-take-the-heat/

Your Houseplant Is Doing More Than Just Sitting There

 

Your Houseplant Is Doing More Than Just Sitting There

Plants have some pretty surprising ways to fend off infections. We often think

of them as just sitting there, but this article dives into how they activate defenses

all over when trouble strikes in one area. This process is called systemic acquired

resistance, and it helps prepare other parts of the plant before they get hit.

The research comes from a study by Dan Smith, focusing on the chemicals

involved. Salicylic acid was the main player everyone knew about, but it takes

about 24 hours to ramp up after an infection. So, scientists figured there must

be something quicker to kick things into gear. It turns out that jasmonate moves

in quickly, within hours, and then salicylic acid follows up to support it. Together,

they create a layered defense system that seems to work well.

Since plants don’t have immune cells or blood to send signals, everything

relies on chemicals moving from cell to cell. Each cell picks up on these signals

and activates defense genes. It sounds complex, but the researchers used

luciferase from bioluminescent bugs to make the plants light up when the

immune response is activated. This allows them to observe the whole process in real-time.

This research is really important for farming because pests and diseases can

destroy up to 40 percent of crops each year. With a growing population, we need

plants that can better withstand these threats. Understanding these natural defenses

could lead to a reduced need for pesticides, which would be a win for public health

and the environment.

The article also challenges the idea of chemophobia, where people think all chemicals

are harmful. In this case, these plant hormones are just part of their survival strategy,

and they might even help address global food issues. Chemistry plays a beneficial role

in biology, its not something to be afraid of.

For a class like CHEM 100, this topic fits perfectly. It connects molecules to real-life

applications, like how they regulate plant systems and promote sustainable farming.

Some sections might feel a bit technical, but overall, it clearly illustrates the connection.

 

Source: “Moment of Science: New study sheds light on plant immune 

responses” by Dan Smith (Mar. 17, 2026)

https://www.13abc.com/2026/03/17/moment-science-new-study-sheds-

light-plant-immune-responses/ 

A single amino acid could determine if your medicines work

Do you know people who swear by Tylenol as a pain reliever and other people who say it doesn’t work for them at all? One of the unsolved mysteries in chemistry is a clear explanation for why medicines work differently in different people. The chemistry of drug development can seem straightforward on the surface. There are receptors on the surface of human cells that respond to signals from things like hormones and drugs and determine how the body reacts. Drug makers create medicines that target these receptors in an effort to treat illness. Although drug makers design drugs that bind tightly to certain receptors, the drugs are not always as effective as expected, and the effectiveness can vary among patients. Research reported in a recent ScienceNewsToday article (based on an ACS Medicinal Chemistry Letters paper) provides a possible explanation for why. 

A team of scientists in Japan studied the histamine H1 receptor, which is involved in allergic reactions, inflammation, and other functions in the body, and how two isomers of a compound called doxepin bind to this receptor. Researchers found that the z isomer bound to the receptor with much higher affinity than the e isomer and that a single amino acid, Thr1123.37, was responsible for the difference. They then created a mutant receptor and studied how each isomer reacted with each receptor. In particular they measured the binding energy and the balance of two thermodynamic forces, enthalpy and entropy, in the binding process. Enthalpy describes how strongly molecules stick together and entropy describes how much freedom they have to move. The researchers discovered that small differences in compounds, such as the difference in a single amino acid, can change the balance of the enthalpy and entropy forces in the bond which can dramatically impact the tightness of the bond.

Differences in binding energy for two different isomers of doxepin

This research may help explain why some drugs work better than others, even when they look very similar. Understanding the impact of the entropy and enthalpy balance on binding can help drug makers design drugs that are even more selective for the target. This article has the potential to reduce chemophobia because it reminds readers that chemistry is essential to maintaining human health. It shows scientists using their knowledge to help people in their everyday lives.

Primary Source:

ScienceNewsToday, Editors of. “This Tiny Molecular Sentinel inside Your Cells Decides How Your Body Heals.” Science News Today, 15 Feb. 2026, www.sciencenewstoday.org/this-tiny-molecular-sentinel-inside-your-cells-decides-how-your-body-heals. 

Secondary Source:

Kaneko, Hiroto, et al. “Enthalpy–entropy trade-off underlies geometric isomer selectivity in histamine H1 receptor–doxepin interaction.” ACS Medicinal Chemistry Letters, vol. 17, no. 2, 27 Jan. 2026, pp. 490–494, https://doi.org/10.1021/acsmedchemlett.5c00696. 

Finding an Extraterrestrial Vacation Destination

Why finding water is not the only hurdle

Finding life elsewhere in the universe might require considering more than one “Goldilocks zone.”

Elen11/iStock/Getty Images Plus

Space exploration has been a major focus of the scientific community ever since the first human was successfully put into space. Learning more about these planets, stars, and other celestial bodies has only grown the curiosity for what might exist in our universe. The biggest mystery that has yet to be solved is identifying a planet that could support human life in the ways that only Earth seems to be able to. 

For a planet to sustain life, certain elements are required to be a part of the planetary composition. The primary compound that researchers look for is water due to nature's dependence on water as a biological solvent and building block for all organisms. What many individuals tend to forget is that the human body is complex and contains many necessary elements that you wouldn't think to be required for survival. "A chemical 'goldilocks zone' may limit which planets can host life" published in Science News, dives into the two biggest secondary essential elements, Phosphorus and Nitrogen. 

While water is necessary for structure and function in biological systems, phosphorus and nitrogen play the vital role of composing the structure of genetic material and various proteins. The natural abundance of these two critical elements is balanced by the presence of oxygen due to how these three elements bind to iron, which is what many planet cores are made of. If more oxygen is present, iron in the mantle will bind with it, enabling more phosphorus in the mantle, but it carries nitrogen into the core. A reduction in oxygen reverses this effect, resulting in higher concentrations of nitrogen in the mantle and less phosphorus. Considering these two processes results in the "goldilocks zone", just the right amount of oxygen to keep ample amounts of both nitrogen and phosphorus available in the mantle for biological processes.

Many more elements are required for human survival, some that you would never think to consider. LibreTexts outlines in this table which elements are found in the bulk of biology, as well as macrominerals and trace elements.

Elements like magnesium are used as cofactors in over 300 enzymatic chemical reactions for energy production and protein synthesis, while calcium and phosphorus are the primary components of bone structures. Trace elements are less commonly found, but still just as important. Iron is the required metal center for heme groups that are found in blood and are responsible for oxygen transfer. The chemistry of life is far more complex than it would seem, and many factors would have to be considered when searching for a suitable planet for humans. Whether or not we ever discover a planet that checks all of these boxes remains a mystery, but that will not stop humanity from chasing the dream.

Primary Reference:

https://www.sciencenews.org/article/chemical-planets-core-life-oxygen

Supporting References:

https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_General_Chemistry%3A_Principles_Patterns_and_Applications_(Averill)/01%3A_Introduction_to_Chemistry/1.09%3A_Essential_Elements_for_Life

https://pmc.ncbi.nlm.nih.gov/articles/PMC3341892/#:~:text=Bone%20is%20composed%20of%20various%20types%20of,as%20well%20as%20to%20form%20new%20bone.

https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/#:~:text=This%20is%20a%20fact%20sheet,are%20kept%20under%20tight%20control.

Molecular Architecture or Magic?

 Metal-Organic Frameworks as the Future for Environmental Science

(Susumu Kitagawa, Richard Robson, and Omar Yaghi, CNN)

        Environmental concerns regarding climate change are at the forefront of science and our future, what if someone told you chemicals contributing to this phenomena could be grabbed right out of the air! Sounds pretty good right? As documented in the CNN article Nobel Prize in chemistry goes to scientist trio for Harry Potter-like work in molecular architecture, the 2025 Nobel laureates, Susumu Kitagawa, Richard Robson, and Omar Yaghi, have opened up many avenues for removing problematic chemicals, harvesting water from the air, and catalyzing reactions in a very unique way. 

        Metal-organic frameworks (MOFs) are carbon based crystalline structures created with a positively charged atom such as copper ions and a complementary chemical group attracted to said ions, for example a nitrile group. Making these structures with "arms" allows for the formation of cavities in which the amazing functionality of MOFs originates.

(Image from the official Nobel Prize X account)

        The uniquely created structure's cavities were first utilized in 1997 when Kitagawa made a breakthrough from developing a molecule that could not only absorb methane, nitrogen, and oxygen but also release it! Remarkably, Kim Jelfs, professor of chemistry at Imperial College London, said, "one gram of a MOF material can have the same surface area inside its pores as a football pitch", hence Heiner Linke, chair of the committee for chemistry, dubbing these compounds akin to "Hermione's handbag" from the Harry Potter novels. Additionally, these molecules have very impressive stability. Take MOF-5 for example, known a classic molecule in the field, that has Zn2+ nodes linked by benzene-1,4-dicarboxylate (BDC), which even as an empty structure can be heated to 300 degrees Celsius without collapsing! 

(MOF-5, image from Wikipedia).

        In terms of practical use, MOFs have already been used by Yaghi's research group to pull water from the desert air of Arizona. How does this happen? MOF's absorb compounds primarily through, van der Waals forces, electrostatic attractions, and hydrogen bonding to later be displaced out of the MOF via changes in pressure, temperature, pH, or by introducing more molecules to displace trapped compounds.

         Great hope is held in the many climate change and chemical reaction applications that could benefit from these compounds. Only time will tell what spells these magical compounds will cast to improve the world.

References: 

https://www.cnn.com/2025/10/08/science/nobel-prize-chemistry-intl

https://x.com/NobelPrize/status/1975861353907695717/photo/1

https://en.wikipedia.org/wiki/MOF-5

Its not the chemicals – Its the knowledge Gap

Science illiteracy and the rise of Chemophobia

Chemophobia is the irrational fear of chemicals which leads people to believe chemicals are

harmful at any level.

Stereotypical outcomes of chemophobia are the general public fearing ingredients they cannot

pronounce, only wanting “natural ingredients”, or avoiding vaccines and other proven health

benefits due to lack of understanding. 30% of individuals report being scared of chemicals,

and nearly all demonstrate a lack of basic scientific understanding proving the clear link between chemical illiteracy and chemophobia. But chemicals are all around us.

The smartphones in our pockets, medicines we take, food we preserve and everyday products

all depend on synthetic chemistry. But Chemophobia isn't really about chemicals, It's about

how gaps in scientific literacy shapes public perception. 

Science literacy, particularly chemical literacy, remains low across much of the public. Only 28% of Americans are considered to have civic scientific literacy, and 44% of Europeans want to “live in a world where chemical substances don't exist”. This demonstrates a clear knowledge gap between scientists and the general public. With many people unable to explain basic concepts such as: toxicity, dose and the difference between hazard and risk; the opportunity for misinformation, fear-based marketing, and distorted risk perception becomes significantly greater. When individuals feel uninformed, they naturally rely on educated guesses, or heuristics, to make decisions. While these heuristics may work in everyday life, when applied to chemical substances many people make biased decisions. 

One of the most powerful assumptions is that “natural’” equates to safety, while “synthetic” products are dangerous or toxic. This is usually because “natural” evokes positive feelings such as purity, health and environment. In contrast, “chemicals” often trigger images of toxins, or pollution. But under scientific scrutiny, this distinction collapses. For example, people without scientific background fall susceptible to biased risk perception of cleaning products labeled as “eco”. Many individuals believe that eco drain cleaners are healthier and safer than regular drain cleaners when both products contain very similar ingredients and the same warning labels highlighting the perception of safety being more important than facts. From a toxicological perspective, the origin of a substance tells little about its safety and what matters is its dose, exposure, and biological interaction, not whether something came from a laboratory or a leaf. 

Additionally, it is widely believed that trace amounts of a substance perceived as harmful can lead people to judge a product as wholly dangerous. 91% of the survey did not realize that the concept of “toxicity” means the dose makes the poison for everything, regardless of the source and identity of a chemical and fewer than a quarter of survey respondents correctly agreed that a small amount of a toxic substance is not necessarily harmful. This stands in contrast to the foundational principle of toxicology that “the dose makes the poison” where even something as “safe” as bananas can become “poisonous” if you eat too much of them. 

Chemophobia, while driven from lack of scientific knowledge, has public consequences. The rise of the anti-vaccine movement, increase in cost of “natural” products and the increased spread of misinformation and fear about everyday products are all consequences of the rise of chemophobia. But evidence suggests that basic scientific understanding reduces extreme fear of chemicals. People who understand dose response relationships and recognize that “natural” and “synthetic” are not safety categories tend to show lower levels of chemophobia. Furthermore, education does not eliminate chemical concerns but refines it. 

To improve scientific literacy, science education should be strengthened at every level and public communication about risk, uncertainty and regulation in a digestible way for the public should be improved. The Royal Society of Chemistry reports that 58% of women and 45% of men not feeling confident enough to talk about chemistry demonstrating a systemic issue in the scientific knowledge gap rather than individual disinterest. If large portions of the public feel unequipped to engage in conversations about chemistry topics, it creates ground for misinformation, and fear-based narratives increasing the chances of chemophobia. The education of students about toxicological principles, especially the difference between hazard and risk as well as synthetic vs natural would help improve perceptions and eradicate chemophobia. 

Reference:

Siegrist, M., Bearth, A. Chemophobia in Europe and reasons for biased risk perceptions.

Nat. Chem. 11, 1071–1072 (2019). https://doi.org/10.1038/s41557-019-0377-8

Image:

‘Free From Sulfates, Phosphates, and Parabens’: What Is Chemophobia and How Is

It Tackled at ITMO | SCAMT

Playing God or Playing Smart? The Ethics of CRISPR

Should CRISPR be banned for use? In a piece from the Innovative Genomics Institute titled “CRISPR Ethics,” the institute outlines the major ethical questions surrounding CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) gene-editing technology. The article explains that CRISPR allows scientists to precisely modify DNA and holds great promise for treating genetic diseases. At the same time, it raises concerns about human germline editing, the possibility of “designer babies,” and the need for strong global oversight. At its core, CRISPR is a chemical system: the Cas9 enzyme catalyzes the hydrolysis of phosphodiester bonds in DNA, allowing scientists to break and reform covalent bonds in the genome. China is mentioned in the context of a major ethical controversy: it describes how, in November 2018, a Chinese scientist, He Jiankui, announced the birth of twin girls whose embryos he had edited with CRISPR (editing the CCR5 gene to purportedly protect them from HIV infection). This action sparked international outcry and condemnation because it violated widely-accepted ethical norms and lacked proper oversight, and He was later sentenced to three years in prison — an event that highlighted the need for clear guidelines and oversight on human embryo editing.

                                            

CRISPR gene-editing systems function by directing Cas enzymes to a targeted location in the genome, where the enzymes make a precise cut in the DNA.   https://www.livescience.com/58790-crispr-explained.html

From a chemistry perspective, CRISPR operates at the molecular level. The Cas9 enzyme cuts DNA by breaking specific chemical bonds in the DNA backbone, relying on principles such as molecular structure, bonding interactions, and enzyme catalysis. The specificity of CRISPR depends on chemical base-pairing interactions between guide RNA and DNA, which are governed by hydrogen bonding and molecular geometry. The effectiveness and safety of CRISPR-based therapies also depend on chemically designed delivery systems that transport gene-editing components into cells. Although often categorized as biology, CRISPR is fundamentally applied molecular chemistry in living systems.

The article places the controversy in a broader social and regulatory context rather than presenting CRISPR as inherently dangerous. It distinguishes between therapeutic uses, such as correcting serious genetic disorders, and enhancement applications that raise deeper ethical concerns. In doing so, it avoids reinforcing chemophobia. Scientists are portrayed not as reckless experimenters, but as actively engaged in ethical reflection and global governance discussions. 

CRISPR-based therapies are advancing within established regulatory frameworks—particularly through the requirements of the U.S. Food and Drug Administration and other global regulators, with early-stage trials (Phase I) focused on safety and dosing and later stages (Phases II and III) designed to generate the efficacy data needed for formal approval. It notes the historic first approval of a CRISPR-based medicine (Casgevy) for sickle cell disease and beta thalassemia, and discusses how financing and reimbursement arrangements (e.g., with state Medicaid programs and the UK’s NHS) are evolving as part of translating these approvals into real-world treatment access. The article also emphasizes that the first personalized CRISPR therapy, developed and delivered in six months, sets an important precedent for rapid regulatory pathways for “platform therapies” in the U.S., potentially shaping how future bespoke and on-demand gene-editing treatments are evaluated and cleared by regulators.

Overall, the article connects chemical principles to real-world medical innovation while also encouraging critical thinking about regulation, risk, and societal responsibility. Rather than promoting fear, it presents CRISPR as a powerful chemical technology that requires careful and informed oversight.

https://innovativegenomics.org/crisprpedia/crispr-ethics/#Introduction 

https://innovativegenomics.org/news/crispr-clinical-trials-2025/