Cheap and quick to produce, these digitally manufactured plasma sensors could help scientists predict the weather or study climate change.

Scientists at MIT have created the first completely digitally manufactured plasma sensors for satellites. These plasma sensors, also known as retarding potential analyzers (RPAs), are used by orbiting spacecraft to determine the chemical composition and ion energy distribution of the atmosphere.

The 3D-printed and laser-cut hardware performed as well as state-of-the-art semiconductor plasma sensors. Due to the manufacturing process, which requires a cleanroom, semiconductor plasma sensors are expensive and require weeks of intricate fabrication. By contrast, these 3D-printed sensors can be produced for tens of dollars in a matter of days.

Due to their low cost and speedy production, the new sensors are ideal for CubeSats. These inexpensive, low-power, and lightweight satellites are often used for communication and environmental monitoring in Earth’s upper atmosphere.

The team of researchers developed RPAs using a glass-ceramic material that is more resilient than traditional sensor materials like silicon and thin-film coatings. By using the glass-ceramic in a fabrication process that was developed for 3D printing with plastics, they were able to construct sensors with complex shapes that can withstand the wide temperature swings a spacecraft would encounter in lower Earth orbit.

“Additive manufacturing can make a big difference in the future of space hardware. Some people think that when you 3D-print something, you have to concede less performance. But we’ve shown that is not always the case. Sometimes there is nothing to trade off,” says Luis Fernando Velásquez-García, a principal scientist in MIT’s Microsystems Technology Laboratories (MTL) and senior author of a paper presenting the plasma sensors.

Joining Velásquez-García on the paper are lead author and MTL postdoc Javier Izquierdo-Reyes; graduate student Zoey Bigelow; and postdoc Nicholas K. Lubinsky. The research is published in Additive Manufacturing.

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In an RPA, plasma passes through a series of electrically charged meshes dotted with tiny holes. As the plasma passes through each mesh, electrons and other particles are stripped away until only ions remain. This figure shows how the meshes fit inside the RPA housing, which aligns the meshes. Credit: Courtesy of the researchers

Versatile sensors

An RPA was first used in a space mission all the way back in 1959. The sensors detect the energy in ions, or charged particles, that are floating in plasma, which is a superheated mix of molecules present in the Earth’s upper atmosphere. Aboard an orbiting spacecraft like a CubeSat, the versatile instruments measure energy and conduct chemical analyses that can help scientists predict the weather or monitor climate change.

The sensors contain a series of electrically charged meshes dotted with tiny holes. As plasma passes through the holes, electrons and other particles are stripped away until only ions remain. These ions create an electric current that the sensor measures and analyzes.

Key to the success of an RPA is the housing structure that aligns the meshes. It must be electrically insulating while also able to withstand sudden, drastic swings in temperature. The researchers used a printable, glass-ceramic material known as Vitrolite that exhibits these properties.

Pioneered in the early 20th century, Vitrolite was often used in colorful tiles that became a common sight in art deco buildings.

The durable material can also withstand temperatures as high as 800 degrees Celsius (1472 degrees Fahrenheit) without breaking down, whereas polymers used in semiconductor RPAs start to melt at 400 degrees Celsius (752 degrees Fahrenheit).

“When you make this sensor in the cleanroom, you don’t have the same degree of freedom to define materials and structures and how they interact together. What made this possible is the latest developments in additive manufacturing,” Velásquez-García says.

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This figure shows an experiment in which the researchers set up their RPA to characterize it as an ion energy distribution sensor. Credit: Courtesy of the researchers

Rethinking fabrication

The 3D printing process for ceramics usually involves ceramic powder that is hit with a laser to fuse it into shapes. However, this process often leaves the material coarse and creates weak points due to the high heat from the lasers.

Instead, the MIT scientists used vat polymerization, a process introduced decades ago for additive manufacturing with polymers or resins. With vat polymerization, a 3D structure is built one layer at a time by submerging it repeatedly into a vat of liquid material, in this case, Vitrolite. Ultraviolet light is used to cure the material after each layer is added, and then the platform is submerged in the vat again. Each layer is only 100 microns thick (roughly the diameter of a human hair), enabling the creation of smooth, pore-free, complex ceramic shapes.

In digital manufacturing, objects described in a design file can be very intricate. This precision allowed the researchers to create laser-cut meshes with unique shapes so the holes lined up perfectly when they were set inside the RPA housing. This enables more ions to pass through, which leads to higher-resolution measurements.

Because the sensors were cheap to produce and could be fabricated so quickly, the team prototyped four unique designs.

While one design was especially effective at capturing and measuring a wide range of plasmas, like those a satellite would encounter in orbit, another was well-suited for sensing extremely dense and cold plasmas, which are typically only measurable using ultraprecise semiconductor devices.

This high precision could enable 3D-printed sensors for applications in fusion energy research or supersonic flight. The rapid prototyping process could even spur more innovation in satellite and spacecraft design, Velásquez-García adds.

“If you want to innovate, you need to be able to fail and afford the risk. Additive manufacturing is a very different way to make space hardware. I can make space hardware and if it fails, it doesn’t matter because I can make a new version very quickly and inexpensively, and really iterate on the design. It is an ideal sandbox for researchers,” he says.

While Velásquez-García is pleased with these sensors, he wants to enhance the fabrication process in the future. Reducing the thickness of layers or pixel size in glass-ceramic vat polymerization could create complex hardware that is even more precise. Furthermore, fully additively manufacturing the sensors would make them compatible with in-space manufacturing. He also wants to explore the use of artificial intelligence to optimize sensor design for specific use cases, such as greatly reducing their mass while ensuring they remain structurally sound.

Reference: “Compact Retarding Potential Analyzers Enabled by Glass-Ceramic Vat Polymerization for CubeSat and Laboratory Plasma Diagnostics” by Javier Izquierdo-Reyes, Zoey Bigelow, Nicholas K. Lubinsky and Luis Fernando Velásquez-García, 13 July 2022, Additive Manufacturing.
DOI: 10.1016/j.addma.2022.103034

This work was funded, in part, by MIT, the MIT-Tecnológico de Monterrey Nanotechnology Program, the MIT Portugal Program, and the Portuguese Foundation for Science and Technology.

Lasers pave the path for finding ancient crust.

Curtin University researchers have discovered evidence of an approximately four billion-year-old piece of the Earth’s crust that exists beneath the South-West of Western Australia by using lasers smaller than a human hair to target microscopic grains of a mineral extracted from beach sand.

The Timescales of Mineral Systems Group at Curtin’s School of Earth and Planetary Sciences, led by Ph.D. student Maximilian Droellner, said the lasers were used to vaporize portions of individual grains of the mineral zircon and revealed where the grains were originally eroded from as well as the geological history of the region. This new discovery helps explains how the planet evolved from being uninhabitable to supporting life.


“There is evidence that an up to four billion-year-old piece of crust about the size of Ireland has been influencing the geological evolution of WA for the past few billions of years and is a key ingredient of rocks formed in WA across this time,” Mr. Droellner states.

“This piece of crust has survived multiple mountain-building events between Australia, India, and Antarctica and appears to still exist at tens of kilometers of depth under the South-West corner of WA. When comparing our findings to existing data, it appears many regions around the world experienced a similar timing of early crust formation and preservation. This suggests a significant change in the evolution of the Earth some four billion years ago, as meteorite bombardment waned, crust stabilized and life on Earth began to establish.”

Research supervisor Dr. Milo Barham, also from the Timescales of Mineral Systems Group within Curtin’s School of Earth and Planetary Sciences, said no large-scale study of this region had been done before and the results, when compared with existing data, had revealed exciting new insights.


“The edge of the ancient piece of crust appears to define an important crustal boundary controlling where economically important minerals are found,” Dr. Barham said.

“Recognising these ancient crustal remnants is important for the future of optimized sustainable resource exploration. Studying the early Earth is challenging given the enormity of time that has elapsed, but it has a profound importance for understanding life’s significance on Earth and our quest to find it on other planets.”

Reference: “A persistent Hadean–Eoarchean protocrust in the western Yilgarn Craton, Western Australia” by Maximilian Dröllner, Christopher L. Kirkland, Milo Barham, Noreen J. Evans and Bradley J. McDonald, 17 June 2022, Terra Nova.
DOI: 10.1111/ter.12610

Mr. Droellner, Dr. Barham, and research co-supervisor Professor Chris Kirkland are affiliated with The Institute for Geoscience Research (TIGeR). Curtin’s flagship Earth Sciences research institute and the research were funded by the Minerals Research Institute of Western Australia.

The move to the launchpad ahead of our Artemis I flight test …

Discussing priorities for national space activities …

And cargo and science head home from the space station … a few of the stories to tell you about – This Week at NASA!

Artemis I Moon Rocket and Spacecraft Moved to the Launch Pad

On the night of August 16, teams at our Kennedy Space Center began the approximately 4-mile move of the Space Launch System or SLS rocket and Orion spacecraft from the Vehicle Assembly Building to Launch Pad 39B, in preparation for the launch of our uncrewed Artemis I flight test. The rocket and spacecraft arrived at the pad the next morning. Artemis I is the first in a series of increasingly complex missions to help us establish a long-term presence on the Moon. The mission also will serve as a stepping stone to sending astronauts to Mars. Artemis I is currently targeted for launch no earlier than August 29.

Vice President Meets with National Space Council in California

Vice President Kamala Harris recently met with the National Space Council at the Chabot Space and Science Center in Oakland, California, the official visitor center for our Ames Research Center. Aerospace companies at the event had the opportunity to display and share their work with the vice president. The vice president – who serves as the chair of the National Space Council – also made a speech, in which she discussed upcoming priorities for national activities in space, including strengthening public-private partnerships and the benefits of space exploration for all.

The SpaceX Dragon cargo craft backs away from the space station moments after undocking from the Harmony module’s forward port during an orbital sunrise. Credit: NASA TV

SpaceX Cargo Dragon Departs from Space Station

On August 19, a SpaceX Dragon cargo resupply spacecraft left the International Space Station and headed back to Earth with more than 4,000 pounds of supplies and scientific experiments for NASA and others. This was SpaceX’s 25th Commercial Resupply Services mission for NASA.

Lucy Team Discovers Moon Around Asteroid Polymele

Another asteroid has been added to the “to visit” list for NASA’s Lucy spacecraft. Lucy’s science team recently discovered that the smallest of the mission’s Trojan asteroid targets, Polymele, has a moon. With this discovery, Lucy is now on track to visit a total of nine asteroids — one main belt asteroid and eight so-called Trojan asteroids, a previously unexplored population of asteroids that lead and follow Jupiter in its orbit around the Sun.

Students watch as their experiments launch aboard a sounding rocket for the RockSat-X program from NASA’s Wallops Flight Facility on August 11, 2022, at 6:09 p.m. EDT. The Terrier-Improved Malemute rocket carried the experiments to an altitude of 99 miles before descending via a parachute and landing in the Atlantic Ocean. Credit: NASA Wallops/Terry Zaperach

NASA Wallops Launches Student Technology Experiments

Our Wallops Flight Facility in Virginia recently helped teams of U.S. college students launch their technology experiments into space. The experiments were launched on a Terrier-Improved Malemute sounding rocket to an altitude of about 99 miles before descending back to Earth by parachute. The investigations were flown through the RockSat-X program, which gives students the experience of building experiments for spaceflight.

NASA Television Transponder Change Effective Monday, August 29

A quick note about an upcoming change for NASA Television. NASA TV programming on the Galaxy 13 domestic satellite is moving from transponder 11 to transponder 15. Currently, both transponders are active, but distribution of NASA TV programming on transponder 11 will end on Monday, August 29. For complete details, please visit go.nasa.gov/transponder.

That’s what’s up this week @NASA

Autistic individuals’ stem cells either create too many or too few brain cells.

Researchers from Rutgers University have discovered evidence of anomalies in very early brain development that may contribute to the neuropsychiatric condition by studying the brain stem cells of people with autism spectrum disorder (ASD).

The results confirm a theory that has long been held by scientists: ASD develops early in fetal development, at a time when brain stem cells are dividing to create the critical elements of a functional brain.


Researchers from Rutgers University studied the brain stem cells, also referred to as neural precursor cells (NPCs) of ASD patients, and published their findings in the journal Stem Cell Reports. They discovered the number of permanent brain cells was either over- or underproduced by the NPCs, which are in charge of making the three major types of brain cells: neurons, oligodendrocytes, and astrocytes.

“The NPCs we studied from all samples showed abnormal proliferation, either ‘too little’ or ‘too much,’ which suggests that poor control of proliferation of brain cells is an important basis for ASD causation,” said Emanuel DiCicco-Bloom, a professor of neuroscience and cell biology, and pediatrics at Rutgers Robert Wood Johnson Medical School and author of the paper. “This study demonstrates at the cellular level that altered proliferation is indeed one likely mechanism of the disorder, supporting implications obtained from previous research.”

The study focused on the stem cell activity of five individuals with ASD, including those with idiopathic autism where there is no known genetic cause, and others with genetically defined 16p11.2 deletion. Those with macrocephaly, a medical term for an abnormally large head, had NPCs that produced too many brain cells. The remaining two patients, who did not have macrocephaly, had NPCs that produced too few brain cells.


ASD is a neurodevelopmental disorder characterized by difficulties with social interactions and communication and the presence of repetitive and restricted behaviors. Most ASD cases are idiopathic. About 15 percent to 20 percent of ASD cases are caused by specific genetic mutations.

NPCs are formed prenatally during a period that stretches from the end of the first trimester through the second, about weeks eight to 24 of the 40-week gestation period of a human fetus.

“We’ve actually measured proliferation of human neural precursors and greatly advanced our understanding,” DiCicco-Bloom said. “In the future, once we have reproduced these studies and extended them, we also may be able to use this knowledge as a biomarker, which could signal when to introduce therapy, or to identify signaling pathways to target with drugs.”

Reference: “Autism NPCs from both idiopathic and CNV 16p11.2 deletion patients exhibit dysregulation of proliferation and mitogenic responses” by Robert Connacher, Madeline Williams, Smrithi Prem, Percy L. Yeung, Paul Matteson, Monal Mehta, Anna Markov, Cynthia Peng, Xiaofeng Zhou, Courtney R. McDermott, Zhiping P. Pang, Judy Flax, Linda Brzustowicz, Che-Wei Lu, James H. Millonig and Emanuel DiCicco-Bloom, 26 May 2022, Stem Cell Reports.
DOI: 10.1016/j.stemcr.2022.04.019


The study was funded by the New Jersey Governor’s Council for Medical Research and Treatment of Autism, the Nancy Lurie Marks Family Foundation for E.D.-B. and J.H.M., the NJ Health Foundation, the Mindworks Charitable Lead Trust and Jewish Community Foundation of Greater MetroWest, the New Jersey Governor’s Council for Medical Research and Treatment of Autism and the Robert Wood Johnson Foundation.

Scientists explain an unusual tsunami.

A new study published in the journal Nature describes the process that produced and propagated an unusual tsunami following the catastrophic explosion of the Hunga Tonga-Hunga Ha’apai in Tonga in early 2022.

The tsunami that followed the massive eruption of the Hunga Tonga-Hunga Ha’apai volcano on January 15, 2022, is thought by scientists to have been exceptional since it had a worldwide reach, a faster propagation rate, unexpectedly high wave heights, and an unheard-of duration.

“The violent explosion of the Hunga Tonga-Hunga Ha’apai volcano in the South Pacific was a source of both noticeable atmospheric waves and an exceptionally fast-traveling global tsunami with minimal dissipation in the far-field. This was the first time that a volcano-triggered tsunami was globally recorded by modern, worldwide dense instrumentation, thus providing a unique opportunity to investigate the role of air-water coupling processes in tsunami generation and propagation” explains Rachid Omira, first author, a researcher at Instituto Dom Luiz, Faculty of Sciences of the University of Lisbon (Portugal).

In this study, the research team looked at satellite, sea-level, and atmospheric data from all over the world and used numerical and analytical models to show that the tsunami was caused by an acoustic-gravity wave that was generated by the volcano explosion and that it traveled several times across the globe. In their conclusions, the scientists provide an exact explanation for the tsunami that was witnessed around the world and make hazard-related recommendations.

“The challenging part of studying the Tonga tsunami was to quantitatively explain all the observed tsunami features that were completely different from those of common tsunamis”, adds Rachid Omira, stating: “A fast-moving atmospheric wave able to excite the ocean surface and pump energy into it was our explanation for this tsunami that “jumped” from an ocean to another and reached the coast of Portugal 10 hours earlier than expected”.

Reference: “Global Tonga tsunami explained by a fast-moving atmospheric source” by R. Omira, R. S. Ramalho, J. Kim, P. J. González, U. Kadri, J. M. Miranda, F. Carrilho, and M. A. Baptista, 13 June 2022, Nature.
DOI: 10.1038/s41586-022-04926-4