Science
Nuclear Propulsion Could Help Get Humans to Mars Faster
This is from a NASA press release dated February 12, 2021…
As NASA’s Perseverance rover homes in on the Red Planet, engineers on the ground are furthering potential propulsion technologies for the first human missions to Mars. NASA is looking at two types of nuclear propulsion systems – nuclear electric and nuclear thermal propulsion.
Nuclear electric propulsion systems use propellants much more efficiently than chemical rockets but provide a low amount of thrust. They use a reactor to generate electricity that positively charges gas propellants like xenon or krypton, pushing the ions out through a thruster, which drives the spacecraft forward. Using low thrust efficiently, nuclear electric propulsion systems accelerate spacecraft for extended periods and can propel a Mars mission for a fraction of the propellant of high thrust systems.
Credits: NASA
Nuclear thermal propulsion technology provides high thrust and twice the propellant efficiency of chemical rockets. The system works by transferring heat from the reactor to a liquid propellant. That heat converts the liquid into a gas, which expands through a nozzle to provide thrust and propel a spacecraft.
NASA, in coordination with the Department of Energy (DOE), is asking industry for preliminary reactor design concepts for a nuclear thermal propulsion system. The agencies plan to fund several efforts to explore different approaches. Future follow-on contracts will generate more detailed reactor designs and build preliminary testing hardware.
“While NASA’s immediate priority is returning humans to the Moon with the Artemis program, we are also investing in ‘tall pole’ technologies that could enable crewed missions to Mars,” said Jim Reuter, associate administrator of NASA’s Space Technology Mission Directorate (STMD). “We look forward to seeing what innovations industry offer in nuclear propulsion as well as fission surface power via a forthcoming request for proposals for that technology.”
Human Missions to Mars
To date, only robotic explorers have traveled to Mars, without the need for returning to Earth. Waiting for optimal planetary alignment for the return trip would require astronauts to loiter at Mars for more than a year, stretching the round-trip mission to more than three years.
NASA’s goal is to minimize the time the crew travels between Earth and Mars to as close to two years as is practical. Space nuclear propulsion systems could enable shorter total mission times and provide enhanced flexibility and efficiency for mission designers.
To keep the round-trip crewed mission duration to about two years, at a minimum, NASA is looking at nuclear-enabled transportation systems to facilitate shorter-stay surface missions. The systems would take advantage of optimal planetary alignment for a low-energy transit for one leg of the trip and the new technology’s enhanced performance to make the higher-energy transit for the other leg.
It’s too soon to say what propulsion system will take the first astronauts to Mars, as there remains significant development required for each approach.
Illustration of a spacecraft with a nuclear-enabled propulsion system. Credits: NASA
Technology Readiness
NASA’s Marshall Space Flight Center in Huntsville, Alabama, leads the agency’s space nuclear propulsion project in partnership with a DOE team that includes scientists and engineers from Idaho National Laboratory, Los Alamos National Laboratory, and Oak Ridge National Laboratory. STMD’s Technology Demonstration Missions program funds the technology development.
Nuclear electric propulsion builds on NASA’s work maturing solar electric propulsion thrusters and systems for Artemis, as well as the development of fission power for the lunar surface. Significant investment has also been made in relevant fuel and reactor technologies for small, terrestrial reactors that could be adapted to space reactors to power electric propulsion. The U.S. government’s aim to establish a fuel fabrication capability has a range of applications, including nuclear propulsion and fission surface power.
Credits: NASA/Mick Speer
Nuclear thermal propulsion has been on NASA’s radar for more than 60 years. The new hardware design and development phase pursued through a request for proposals released Feb. 12, 2021, builds on existing efforts to mature crucial elements of a nuclear thermal propulsion system.
NASA, in partnership with DOE, is developing and testing new fuels that use low-enriched uranium for space applications to see how they perform under the extreme thermal and radiation environments needed for nuclear thermal propulsion. NASA is working closely with DOE, industry, and universities to put fuel samples in research reactors at Idaho National Laboratory’s Transient Reactor Test (TREAT) facility and the Massachusetts Institute of Technology Nuclear Reactor Laboratory for nuclear testing. The team is also performing non-nuclear testing in simulated reactors at Marshall test facilities.
“The reactor underpinning a nuclear thermal propulsion system is a significant technical challenge due to the very high operating temperatures needed to meet the propulsion performance goals,” explained Anthony Calomino, NASA’s nuclear technology portfolio lead within STMD.
While most of the engine operates at modest temperatures, materials in direct contact with the reactor fuel must be able to survive temperatures above 4,600 degrees Fahrenheit. NASA and DOE have been working with industry on a viable approach, and industry will now develop preliminary designs to meet this challenge.
Technology Infusion
“We’re exploring both nuclear electric and nuclear thermal propulsion options for crewed Mars missions,” Calomino said. “Each technology has its unique advantages and challenges that need to be carefully considered when determining the final preference.”
Whichever propulsion system is ultimately chosen, the fundamentals of nuclear propulsion can enable robust and efficient exploration beyond the Moon. NASA will continue to develop, test, and mature various propulsion technologies to reduce risk and inform the Mars transport architecture.
Source: NASA
https://stmdailynews.com/category/science/
health and wellness
Lactose intolerance is actually the human norm – but racism, the US government and business interests have made it into a condition
Lactose intolerance is the global human norm, but Western dietary standards, government policies and commercial interests helped frame it as a medical deficiency.
Hilary Smith, University of Denver
Lactose intolerance makes drinking milk or eating ice cream a literal pain. For some people, eating a dairy treat can lead to bloating, nausea and diarrhea. You might’ve experienced its effects yourself. If so, you may think of lactose intolerance as a defect rather than the norm.
But did you know that most people in the world today are lactose intolerant – and that the condition itself was invented in the 1960s?
“Surely you mean discovered, not invented,” I hear you saying. I don’t. As a historian who has traced the origins of nutrition-science ideas, I have chosen the word “invented” on purpose.
Inventing lactose intolerance
Variations in people’s ability to digest lactose first came to scientists’ attention after American dairy producers found a way to rid themselves of a postwar milk surplus. To offload what they couldn’t sell, they looked to the government to intervene. And it did, buying the excess and embedding it in school lunches and other places with publicly funded meals.
Suddenly, many people who had not habitually drunk milk were consuming it regularly, including not only some Americans but also people overseas. Part of that same milk surplus found its way into school lunches in places such as Japan and Taiwan in the 1950s as the American government began to sell milk to allies during the Cold War.
Many of the groups drinking milk regularly for the first time did not like it. In fact, it made them feel sick. Intrigued, scientists set up experiments to figure out why. In a 1966 study comparing how Black and white people incarcerated in Baltimore metabolized lactose, researchers found that Black participants had lower levels of lactase – the enzyme that breaks down lactose – in their guts.
To the white scientists conducting this study, the trouble that the Black prisoners had digesting milk looked like an “inborn error of metabolism.” They assumed that the normal human state was lactose tolerance and that the lactose intolerant had inherited a genetic mutation.
It was only after years more work with research participants of many races that experts realized that, as one National Institutes of Health official put it in 1981, “lactose intolerance is a normal physiological condition, shared by every adult animal except for certain ethnic and racial groups in man.” People of northern European descent, it turned out, were the weird ones. It was their ancestors who had passed down a genetic mutation – one that made them able to digest milk after infancy.
In short, what scientists discovered in the 1960s was that different bodies process milk differently. What they invented was the idea that lactose intolerance is a defect. Accepting that framing would mean nearly two-thirds of the human population – the estimated prevalence of lactose intolerance worldwide – is defective.
Instead of acknowledging that dairy-free diets can be healthy, people innovated ways to overcome this supposed disability so everyone could consume more.
Nutritional imperialism
Lactose intolerance is one example of what I call nutritional imperialism: a way of thinking that treats white diets as the norm and everyone else’s as an aberration.
Nutritional imperialism was common in the 20th century, when scientists thought that not only milk-rich but also meat-heavy diets were best; they considered diets outside of the United States and Europe too vegetarian. Some also argued that wheat flour, not rice, ought to be the universal staple.
The same bias applied to bodies. Besides faulty lactose digestion, nonwhite bodies were accused of other failures, too, such as aldehyde dehydrogenase deficiency, an inability to digest alcohol quickly. The less technical term for this may be more familiar: Asian flush.
Such differences might have been thought of as variety, just another way of being human. Instead, each became a deficiency.
Many people today have inherited and perpetuated this way of thinking without knowing it, including those who are deemed deficient by it. In 1959, the director of Japan’s nutrition bureau declared that “rice-eating peoples” such as the Japanese were “resigned and passive” and could correct this by imitating Western diets and switching to wheat.
Today, the most prominent scientist promoting the idea that Asian flush is a disease is a geneticist of Taiwanese descent who started a research consortium to study “the most common human enzymopathy in the world.”
The Chinese Nutrition Society placed a tall glass of milk next to its 2022 Food Guide Plate – never mind estimates that the vast majority of Han Chinese, the largest ethnic group in China and worldwide, are lactose intolerant.
Turning sickness back into difference
Science that pathologizes difference helps racism persist.
In recent years, white supremacists have embraced the concept of lactose intolerance as a distinguishing debility of nonwhite people. Social media users have copied and pasted a map of the geographic distribution of lactose tolerance originally published in the scientific journal Nature into racist chat threads on the online discussion forum 4chan.
In 2017, internet trolls disrupted an anti-racist art installation with neo-Nazi chants and messily downed jugs of milk to accentuate their white identity.
Turning a lactose-digestion difference into a deficiency has done more to reinforce narratives of racial hierarchy than to improve public health. So here’s a suggestion: If you enjoy eating dairy, keep doing it; if you don’t, don’t – and know that there is nothing wrong with you.
Hilary Smith, Professor of History, University of Denver
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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News
FAA Certifies Boeing 737-7: What It Means for Airlines and the 737 MAX Program
The FAA has certified Boeing’s new 737-7, clearing the smallest 737 MAX variant for service as Boeing and Southwest prepare for first deliveries.
The U.S. Federal Aviation Administration has certified Boeing’s new 737-7, granting the company an amended type certificate that clears the smallest member of the 737 MAX family for commercial service. The milestone closes a multi-year certification effort and puts the focus on execution: Boeing and launch customer Southwest Airlines say preparations are underway to support first deliveries.
For STM Daily News readers, the headline isn’t just “another plane gets approved.” It’s a signal that Boeing has now cleared a key MAX variant designed for long-range flexibility in a smaller footprint—an aircraft type airlines can use to open or defend routes where demand is strong, but not strong enough to justify a larger narrowbody.
What FAA certification means
An amended type certificate means the FAA has approved the 737-7’s design as compliant with commercial aviation regulations. In practical terms, certification allows airlines to place the aircraft into revenue service once deliveries begin and operator-specific steps—training, manuals, maintenance programs, and entry-into-service planning—are completed.
Boeing also said the FAA updated Boeing Production Certificate No. 700 (PC 700) to include the 737-7, supporting production and delivery activities.
Why the 737-7 matters in the MAX lineup
Boeing positions the 737-7 as the smallest and longest-range member of the 737 MAX family. The company says it typically seats 135 to 160 passengers in a two-class configuration and offers a range of up to 3,800 nautical miles (7,040 km). That combination matters because it gives airlines more options to fly longer “thin” routes—markets where frequency and reach matter more than packing in additional seats.
Boeing also highlights performance for operations out of high-altitude airports and in hot climates, where takeoff performance and payload-range tradeoffs can shape fleet decisions.
Efficiency claims: fuel, emissions, and noise
Boeing says the 737-7, like other 737 MAX jets, reduces fuel use and CO2 emissions by 20% and cuts the noise footprint by 50% compared to the airplanes it typically replaces. For airlines, those improvements typically show up in two ways:
- Route economics: lower fuel burn can improve margins on longer sectors and reduce exposure to fuel-price swings.
- Operational constraints: quieter aircraft can help with airport noise requirements and community pressure, while lower emissions support sustainability targets.
Inside the certification effort
Boeing said the certification program began in 2018 and included more than 1,000 hours of flight and ground testing, extensive system safety analysis, and human factors reviews. The company also noted an updated engine anti-ice system to address a potential condition discovered during flight testing.
Boeing Commercial Airplanes President and CEO Stephanie Pope called the certification “important” validation of the airplane’s design and the work of the MAX development team. Mike Sinnett, senior vice president of Product Strategy, Product Development and Development Programs, said Boeing held regular discussions with the FAA and that the process has sharpened the company’s understanding of current regulatory requirements—knowledge Boeing expects will accelerate future development with a renewed emphasis on human factors, safety, and quality.
What to watch next
With certification complete, the next phase is about delivery timing and real-world deployment.
- First deliveries to Southwest: Boeing and Southwest are preparing for delivery of the first airplane, including updates to final configuration.
- Production stability: certification removes a major hurdle, but supply chain health and production cadence will determine how quickly the 737-7 shows up in airline schedules.
- The 737-10 timeline: Boeing reiterated it is working to certify the 737-10 this year, keeping attention on how quickly the final MAX variant clears regulatory review.
The bigger MAX picture
Boeing said the 737 MAX family order book stands at more than 7,200 airplanes, with more than 2,300 delivered through the end of June 2026. The 737-7’s certification adds another deliverable product to that portfolio—one aimed at airlines that want long range without stepping up to a larger gauge.
Bottom line
FAA certification of the 737-7 is a meaningful milestone for Boeing and for airlines looking for a smaller narrowbody with long-range capability. The real test now is operational: turning certification into on-time deliveries and reliable entry into service—while the industry watches Boeing’s push to certify the 737-10.
Related Links
- Boeing 737 MAX family overview (manufacturer background/specs): https://www.boeing.com/commercial/737max/
- FAA Aircraft Certification (how type certification works): https://www.faa.gov/aircraft/air_cert/
- FAA Airworthiness Directives (regulatory actions database): https://www.faa.gov/regulations_policies/airworthiness_directives
- Southwest Airlines newsroom (launch customer context / fleet updates): https://www.swamedia.com/
- Boeing Commercial Airplanes newsroom (for follow-ups and official updates): https://boeing.mediaroom.com/news-releases?item=130821
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Source:
Boeing (PRNewswire), Aug. 3, 2026 — “U.S. FAA certifies new Boeing 737-7 airplane.”
Nature
What in the Heck Is a Sweat Bee? Turns Out, My Wife Wasn’t Making It Up
My wife Rebecca said she thought a sweat bee stung her. I thought she was making it up. Turns out, sweat bees are very real—and their strange name actually makes perfect sense.
It started with a conversation with my wife, Rebecca.
She mentioned that she thought she’d been stung by something called a “sweat bee.”
My immediate reaction was basically:
“What in the heck is a sweat bee?”
I’ll admit it. For a moment, I thought she was making the whole thing up. 😂
A sweat bee? Really?
It sounded like one of those names somebody invents when they don’t know what actually stung them.
“It wasn’t a regular bee. It was a… uh… sweat bee!”
So naturally, I asked ChatGPT the same question: What in the heck is a sweat bee?
Well, Rebecca gets this round.
Sweat bees are absolutely real.
And Yes, They’re Interested in Your Sweat
Sweat bees belong primarily to the Halictidae family, a large group of generally small bees found around the world.
Some are rather ordinary-looking little insects, while others are surprisingly flashy, sporting metallic shades of green, blue, bronze or gold.
But here’s where they earned that wonderfully unfortunate name.
Some sweat bees are attracted to human perspiration.
They’re not after you because they’re angry, and they’re certainly not tiny vampire bees. They’re interested in the salt and minerals in your sweat.
In other words, after you’ve been outside working, gardening, exercising or simply trying to survive a hot summer afternoon, a sweat bee may look at you and think:
“Hey! Free electrolytes!”
Wait…They Can Sting Too?
Unfortunately for Rebecca, there’s another part of her story that checks out.
Female sweat bees can sting.
They’re generally not aggressive and aren’t flying around looking for people to attack. But if one gets trapped against your skin, squeezed or swatted, it may defend itself.
Their sting is generally considered relatively mild compared with those of many other bees and wasps—but “relatively mild” probably isn’t much consolation when you’re the person who just got stung.
So, Rebecca, I officially withdraw my skepticism.
Mostly.
Don’t Declare War on Them
As annoying as having a tiny bee land on your sweaty arm might be, sweat bees are actually beneficial insects.
They’re important pollinators, visiting wildflowers, garden plants and agricultural crops and carrying pollen from flower to flower.
So if one lands on you, gently brushing or blowing it away is probably a better idea than swatting it against your skin.
And that’s today’s unexpected nature lesson.
Sweat bees are real.
They really are attracted to sweat.
The females really can sting.
And, perhaps most importantly…
My wife was right.
There. I said it.
I’m sure I’ll never hear the end of this one. 😂
Related Links
- University of Arizona Cooperative Extension — Arizona Bee Identification Guide — A useful Arizona-focused guide that includes sweat bees and explains their appearance, size, nesting behavior and attraction to salt in perspiration.
- USDA Natural Resources Conservation Service — Native Bees and Their Favorite Flowers — More information about native pollinators and the important role sweat bees play around wildflowers.
- USDA Forest Service — Bee Basics — A broader guide to North American bees, including the colorful metallic members of the sweat bee family.
- Smithsonian National Museum of Natural History — Sweat Bee — See an actual female sweat bee specimen (Augochlorella aurata) and its scientific classification.
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