While listening in on the atmosphere, a team of researchers from the U.S. military’s Defense Advanced Research Projects Agency (DARPA) picked up unexpected disturbances caused by a SpaceX rocket plummeting through the atmosphere toward its landing site.
DARPA’s AtmoSense program seeks to use Earth’s atmosphere as a global sensor by measuring acoustic and electromagnetic waves propagating through the atmosphere, and attempting to trace them back to a specific disturbance event that took place on Earth. In doing so, DARPA hopes to be able to trace underground explosions or other national security threats using the signals detected from the atmosphere.
During its latest round of listening to the atmosphere, a team used AtmoSense to study sound waves created by controlled explosions in New Mexico. While conducting this work, the team behind the program made an unplanned discovery after noticing something unusual in the sensor data.
“As the team was looking at the data, they saw a huge drop in what’s called total electron content that puzzled them,” Michael Nayak, program manager of AtmoSense, said in a statement. “Imagine that you have water going through a hose. That’s a flow of electrons, and if you put your fist in front of the hose, you’ll notice a significant drop in water volume coming out of the hose.”
After analyzing the data, the team was able to trace the disturbance to a SpaceX Falcon 9 rocket reentry that took place on the same day as the test. “Then they decided to pull other SpaceX reentry data, across dozens of launches, to see if they could spot a similar electron drop,” Nayak added. “The phenomenon is highly repeatable.”
Using AtmoSense, the team inadvertently discovered a new technique to identify objects reentering through Earth’s atmosphere, according to Nayak. The researchers behind the program will share the most recent results from AtmoSense during an upcoming virtual workshop being held from April 15 to 17.
Falcon 9 is the hardest working rocket in the game, with over 450 missions under its belt. SpaceX’s Falcon 9 is a partially reusable, two-stage rocket that launches payloads into orbit, then returns to Earth for a controlled landing, allowing its first stage to be recovered and reused.
A dissolvable pacemaker that’s smaller than a grain of rice and powered by light could become an invaluable tool for saving the lives of newborn infants., The device can be implanted noninvasively via syringe, and may also be useful for adult patients dealing with certain heart defects. The medical breakthrough is detailed in a study published April 2 in Nature.
Roughly one percent of infants are born with heart defects every year. The majority of these cases only require a temporary implant for about seven days to allow time for the heart to naturally self-repair. But for low-resource regions of the world lacking access to advanced medical care, what should be a simple procedure can often end in tragedy. Meanwhile, the current standard for temporary pacemakers in adults also presents difficulties. Most procedures involve surgeons sewing electrodes directly onto the heart, then attaching those electrodes to an external pacing box using wires that exit a patient’s chest. Doctors remove the electrodes once they are no longer needed, but post-surgery risks include infection, damaged tissue, dislodgment, and blood clots. The wires sometimes also become encased in scar tissue, presenting further complications.
“That’s actually how Neil Armstrong died. He had a temporary pacemaker after a bypass surgery. When the wires were removed, he experienced internal bleeding,” experimental cardiologist and study co-lead Igor Efimov explained in a statement.
In 2021, a Northwestern University team including Efimov unveiled a quarter-sized, biodegradable temporary pacemaker without cumbersome batteries, rigid components, or wiring. The device relies on near-field communication protocols similar to those used in RFID tags and smartphones to complete electronic payments. For this to work, however, the pacemaker needed to include a built-in antenna to relay radio frequency commands.
When the wearable device (left) detects an irregular heartbeat, it emits light to activate the pacemaker. These short pulses—which penetrate through the patient’s skin, breastbone and muscles—control the pacing. Credit: John Rogers / Northwestern University
“Our original pacemaker worked well. It was thin, flexible and fully resorbable. But the size of its receiver antenna limited our ability to miniaturize it,” said its co-creator and bioelectronics pioneer John Rogers.
Rogers, Efimov, and collaborators spent the next few years researching ways to shrink their temporary pacemaker to even smaller proportions. They eventually realized they could swap out the radio antenna for a design that instead relies on light-based data transmission. They also replaced the original device’s near-field communication power source with a galvanic cell—a type of battery that converts chemical energy into electrical energy. In the new version, the pacemaker relies on two metal electrodes that generate an electrical current after interacting with surrounding biofluids. This current is then directed to stimulate and regulate the heart through a miniscule, infrared light-activated switch installed on the battery’s opposite side.
From left to right: Traditional pacemaker, leadless pacemaker, and new bioresorbable pacemaker. Credit: John Rogers / Northwestern University
“Infrared light penetrates very well through the body,” said Efimov. “If you put a flashlight against your palm, you will see the light glow through the other side of your hand. It turns out that our bodies are great conductors of light.”
Because the human heart requires only a small amount of electrical stimulation, researchers were able to shrink their next-generation pacemaker even smaller. The final result is a 1-millimeter-thick device measuring just 1.8 mm wide and 3.5 mm long that is still capable of delivering as much electrical stimulation as a standard pacemaker.
“We have developed what is, to our knowledge, the world’s smallest pacemaker,” Rogers said.
Given its materials safely dissolve over time, the pacemaker also doesn’t require any follow-up invasive surgery to remove it. This dramatically cuts down on the potential for post-op complications and trauma.
But why stop at just one miniature pacemaker? Efimov, Rogers, and collaborators believe that further advancements could allow the deployment of multiple devices across the heart. Once implanted, designers could coordinate them to move independently or together based on specific light wavelengths. This could lead to more complex synchronization therapies, including those that treat arrhythmias.
“We also could incorporate our pacemakers into other medical devices like heart valve replacements, which can cause heart block,” suggested Efimov.
The device’s size also means it can be incorporated into other implantable tools such as transcatheter aortic valve replacements, pain inhibitors, as well as nerve and bone restoration techniques. These future possibilities, however, all trace back to the team’s original goal.
“Our major motivation was children,” said Efimov. “Now, we can place this tiny pacemaker on a child’s heart and stimulate it with a soft, gentle, wearable device.”
Scientists announced on Wednesday (April 2) that they successfully fermented miso aboard the International Space Station, marking the first deliberate food fermentation in space that may open up new culinary possibilities for astronauts on long-term missions.
The traditional Japanese condiment is a fermented soybean paste made by combining cooked soybeans, salt and koji, which is a mold culture typically grown on rice or barley. The fermentation process can last anywhere from a few months to several years, producing a paste with a rich, umami flavor used in soups, sauces and various other dishes. Previous research found that astronauts tend to undereat in space despite having food tailored to their nutritional needs, possibly due to changes in the perceived flavor of the food. Indeed, astronauts themselves have reported a reduced sense of taste and smell while in space, and have said that they prefer salty, spicy and umami-rich foods.
Food fermentation could help address these challenges, and while a few fermented products, such as kimchi and wine, have been sent to the ISS, no actual fermentation process has been carried out in space until now. Joshua Evans, who leads a research group called the Sustainable Food Innovation at the Danish Technical University, and his colleagues set out to determine whether fermentation was possible in space and, if so, how foods fermented in space would compare in taste to their Earth-based counterparts.
In March 2020, the team sent a small container of high-koji, low-salt "miso-to-be" to the ISS to ferment for a month before returning it to Earth.
Two other miso batches that were packed into identical plastic containers and kept frozen until the start of the experiment were fermented here on Earth to act as controls: one in Cambridge, Massachusetts in the U.S., and the other in Copenhagen, Denmark. Once the ISS miso was back on Earth, the team analyzed its microbial communities, flavor compounds and sensory properties.
"Overall, the space miso is a miso," the team wrote in their paper describing the findings.
Packaged miso pre-fermentation on the International Space Station. (Image credit: Jimmy Day)
The researchers found that the ISS miso fermented successfully, and all three samples mostly contained similarly salty umami flavor profiles. The ISS miso is therefore recognizable and safe, the team says, with a specific taste that could satisfy astronauts’ need for flavor while delivering a high nutritional value.
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The ISS miso did have a more roasted, nutty flavor than Earth miso does, the researchers noticed, likely due to the effects of microgravity and increased radiation in the low Earth orbit environment where the ISS is. Those conditions could have sped up fermentation, the study notes.
In this photo, the space miso is labeled "861." (Image credit: Maggie Coblentz)Miso gets a close-up. (Image credit: Josh Evans)
Down the line, these findings can be harnessed to create other types of flavorful fermented foods in space.
"Our study opens up new directions to explore how life changes when it travels to new environments like space," Evans said in a statement. "It could invite new forms of culinary expression, expanding and diversifying culinary and cultural representation in space exploration as the field grows."
A paper about this space miso research was published on Wednesday (April 2) in the journal iScience.
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