Aurelia Butler

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    New nanosatellite tests autonomy in space

    In May 2022, a SpaceX Falcon 9 rocket launched the Transporter-5 mission into orbit. The mission contained a collection of micro and nanosatellites from both industry and government, including one from MIT Lincoln Laboratory called the Agile MicroSat (AMS).

    AMS’s primary mission is to test automated maneuvering capabilities in the tumultuous very low-Earth orbit (VLEO) environment, starting at 525 kilometers above the surface and lowering down. VLEO is a challenging location for satellites because the higher air density, coupled with variable space weather, causes increased and unpredictable drag that requires frequent maneuvers to maintain position. Using a commercial off-the-shelf electric-ion propulsion system and custom algorithms, AMS is testing how well it can execute automated navigation and control over an initial mission period of six months.

    “AMS integrates electric propulsion and autonomous navigation and guidance control algorithms that push a lot of the operation of the thruster onto the spacecraft — somewhat like a self-driving car,” says Andrew Stimac, who is the principal investigator for the AMS program and the leader of the laboratory’s Integrated Systems and Concepts Group.

    Stimac sees AMS as a kind of pathfinder mission for the field of small satellite autonomy. Autonomy is essential to support the growing number of small satellite launches for industry and science because it can reduce the cost and labor needed to maintain them, enable missions that call for quick and impromptu responses, and help to avoid collisions in an already-crowded sky.

    AMS is the first-ever test of a nanosatellite with this type of automated maneuvering capability.

    AMS uses an electric propulsion thruster that was selected to meet the size and power constraints of a nanosatellite while providing enough thrust and endurance to enable multiyear missions that operate in VLEO. The flight software, called the Bus Hosted Onboard Software Suite, was designed to autonomously operate the thruster to change the spacecraft’s orbit. Operators on the ground can give AMS a high-level command, such as to descend to and maintain a 300-kilometer orbit, and the software will schedule thruster burns to achieve that command autonomously, using measurements from the onboard GPS receiver as feedback. This experimental software is separate from the bus flight software, which allows AMS to safely test its novel algorithms without endangering the spacecraft.

    “One of the enablers for AMS is the way in which we’ve created this software sandbox onboard the spacecraft,” says Robert Legge, who is another member of the AMS team. “We have our own hosted software that’s running on the primary flight computer, but it’s separate from the critical health and safety avionics software. Basically, you can view this as being a little development environment on the spacecraft where we can test out different algorithms.”

    AMS has two secondary missions called Camera and Beacon. Camera’s mission is to take photos and short video clips of the Earth’s surface while AMS is in different low-Earth orbit positions.

    “One of the things we’re hoping to demonstrate is the ability to respond to current events,” says Rebecca Keenan, who helped to prepare the Camera payload. “We could hear about something that happened, like a fire or flood, and then respond pretty quickly to maneuver the satellite to image it.”

    Keenan and the rest of the AMS team are collaborating with the laboratory’s DisasterSat program, which aims to improve satellite image processing pipelines to help relief agencies respond to disasters more quickly. Small satellites that could schedule operations on-demand, rather than planning them months in advance before launch, could be a great asset to disaster response efforts.

    The other payload, Beacon, is testing new adaptive optics capabilities for tracking fast-moving targets by sending laser light from the moving satellite to a ground station at the laboratory’s Haystack Observatory in Westford, Massachusetts. Enabling precise laser pointing from an agile satellite could aid many different types of space missions, such as communications and tracking space debris. It could also be used for emerging programs such as Breakthrough Starshot, which is developing a satellite that can accelerate to high speeds using a laser-propelled lightsail.

    “As far as we know, this is the first on-orbit artificial guide star that has launched for a dedicated adaptive optics purpose,” says Lulu Liu, who worked on the Beacon payload. “Theoretically, the laser it carries can be maneuvered into position on other spacecraft to support a large number of science missions in different regions of the sky.”

    The team developed Beacon with a strict budget and timeline and hope that its success will shorten the design and test loop of next-generation laser transmitter systems. “The idea is that we could have a number of these flying in the sky at once, and a ground system can point to one of them and get near-real-time feedback on its performance,” says Liu.

    AMS weighs under 12 kilograms with 6U dimensions (23 x 11 x 36 centimeters). The bus was designed by Blue Canyon Technologies and the thruster was designed by Enpulsion GmbH.

    Legge says that the AMS program was approached as an opportunity for Lincoln Laboratory to showcase its ability to conduct work in the space domain quickly and flexibly. Some major roadblocks to rapid development of new space technology have been long timelines, high costs, and the extremely low risk tolerance associated with traditional space programs. “We wanted to show that we can really do rapid prototyping and testing of space hardware and software on orbit at an affordable cost,” Legge says.

    “AMS shows the value and fast time-to-orbit afforded by teaming with rapid space commercial partners for spacecraft core bus technologies and launch and ground segment operations, while allowing the laboratory to focus on innovative mission concepts, advanced components and payloads, and algorithms and processing software,” says Dan Cousins, who is the program manager for AMS. “The AMS team appreciates the support from the laboratory’s Technology Office for allowing us to showcase an effective operating model for rapid space programs.”

    AMS took its first image on June 1, completed its thruster commissioning in July, and has begun to descend toward its target VLEO position. More

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    Using game engines and “twins” to co-create stories of climate futures

    Imagine entering a 3D virtual story world that’s a digital twin of an existing physical space but also doubles as a vessel to dream up speculative climate stories and collective designs. Then, those imagined worlds are translated back into concrete plans for our physical spaces.

    Five multidisciplinary teams recently convened at MIT — virtually — for the inaugural WORLDING workshop. In a weeklong series of research and development gatherings, the teams met with MIT scientists, staff, fellows, students and graduates as well as other leading figures in the field. The theme of the gathering was “story, space, climate, and game engines.”

    “WORLDING illustrates the emergence of an entirely new field that fuses urban planning, climate science, real-time 3D engines, nonfiction storytelling, and speculative fiction,” says Katerina Cizek, lead designer of the workshop at Co-Creation Studio, MIT Open Documentary Lab. “And co-creation is at the core of this field that allows for collective, democratic, scientific and artistic processes.” The research workshop was organized by the studio in partnership with Unity Software.

    The WORLDING teams met with MIT scholars to discuss diverse domains, from the decolonization of board games, to urban planning as acts of democracy, to behind the scenes of a flagship MIT Climate Challenge project.

    “Climate is really a whole-world initiative,” said Noelle Selin, an MIT atmospheric chemistry professor, in a talk at WORLDING. Selin co-leads an MIT initiative that is digitally twinning the Earth to harness enormous volumes of data for improved climate projections and put these models into the hands of diverse communities and stakeholders.

    “Digital twinning” is a growth market for the game engine industry, in verticals such as manufacturing, architecture, finance, and medicine. “Digital twinning gives teams the power to ideate,” said Elizabeth Baron, a senior manager of enterprise solutions at Unity in her talk at WORLDING. “You can look at many things that maybe aren’t even possible to produce. But you’re the resource. Impact is very low, but the creativity aspect is very high.”

    That’s where the story and media experts come in. “Now, more than ever, we need to forge shared narratives about the world that we live in today and the world that we want to build for the future. Technology can help us visualize and communicate those worlds,” says Marina Psaros MCP ’06, head of sustainability at Unity, lead on WORLDING at Unity, and a graduate of the MIT Department of Urban Studies and Planning.

    In his talk on the short history of WORLDING, media scholar William Uricchio, MIT professor of comparative media studies and founder of the Open Documentary Lab, suggested that story and space come together in these projects that create new ways of knowing. “Story is always a representation,” he says. “It’s got a fixity and coherence to it, and play is — and, I would argue, worlds are —  all about simulation. Simulation in the case of digital twinning is capable of generating countless stories. It’s play as a story-generator, but in the service of envisioning a pluralistic and malleable future.”

    Fixed dominant narratives and game mechanics that underpin board games have been historically violent and unjust, says MIT Game Lab scholar Mikael Jakkobson, who shared findings for his upcoming book on the subject with the cohort. He argues that board games are built on underlying ideas of  “exploration, expansion, exploitation, and extermination. And, as it happens, those are also good ways of thinking about the mechanics of Western colonialism.”

    To counter these hegemonic mechanics and come up with new systems, community is vital, and urban planning is a discipline that plays a huge role in the translation of space, story, and democracy. Ceasar MacDowell, an MIT professor of the practice of civic design, told the WORLDING cohort that urban planning needs to expand its notion of authorship. He is working on systems (from his current position at the Media Lab) that not only engage the community in conversations but also prompt “the people who have been in conversations to actually make sense of them, do the meaning-making themselves, not to have external people interpret them.” These become dynamic layers of both representation and simulation that are not, as Uricchio suggests, fixed. 

    USAID Chief Climate Officer Gillian Calwell visited the group with both sharp warnings and warm enthusiasm: “When it comes to climate, this world isn’t working so well for us; we better start envisioning the new ones, and fast … We don’t have time to convince people that this is happening anymore. Nor do we need to. I think most of the world is having the hands-on, up-close-and-personal experience with the fact that these impacts are coming faster and more furiously than even the scientists had predicted. But one thing we do need help with on a more hopeful note is visualizing how the world could be different.”

    The WORLDING workshop is designed and inspired by the ideas and practices charted in the Co-Creation Studio’s new MIT Press book, “Collective Wisdom: Co-Creation Media for Equity and Justice,” which insists that “No one person, organization, or discipline can determine all the answers alone.”

    The five multidisciplinary teams in this first WORLDING cohort were diverse in approach, technology, and geography. For example, one is an Indigenous-led, land-based, site-specific digital installation that seeks to envision a future in which, once again, the great herds of buffalo walk freely. Another team is creating 3D-modeled biome kits of the water systems in the drought-stricken American West, animated by interviews and data from the communities living there. Yet another team is digitally twinning and then re-imagining a sustainable future in the year 2180 for a multi-player virtual reality game in a Yawanawà Shukuvena Village in the rainforests of Brazil.

    “While our workshop design was focused on developing and researching these incredible, interdisciplinary projects, we also hope that WORLDING can set an example for similar initiatives across global sectors where distances and varied expertise are not limitations but opportunities to learn from one another,” says Srushti Kamat, WORLDING producer and MIT creative media studies/writing grad.

    Most of the talks and presentations from the WORLDING workshop are available as archived videos at cocreationstudio.mit.edu/worlding-videos. More

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    in Environment

    MIT Policy Hackathon produces new solutions for technology policy challenges

    Almost three years ago, the Covid-19 pandemic changed the world. Many are still looking to uncover a “new normal.”

    “Instead of going back to normal, [there’s a new generation that] wants to build back something different, something better,” says Jorge Sandoval, a second-year graduate student in MIT’s Technology and Policy Program (TPP) at the Institute for Data, Systems and Society (IDSS). “How do we communicate this mindset to others, that the world cannot be the same as before?”

    This was the inspiration behind “A New (Re)generation,” this year’s theme for the IDSS-student-run MIT Policy Hackathon, which Sandoval helped to organize as the event chair. The Policy Hackathon is a weekend-long, interdisciplinary competition that brings together participants from around the globe to explore potential solutions to some of society’s greatest challenges. 

    Unlike other competitions of its kind, Sandoval says MIT’s event emphasizes a humanistic approach. “The idea of our hackathon is to promote applications of technology that are humanistic or human-centered,” he says. “We take the opportunity to examine aspects of technology in the spaces where they tend to interact with society and people, an opportunity most technical competitions don’t offer because their primary focus is on the technology.”

    The competition started with 50 teams spread across four challenge categories. This year’s categories included Internet and Cybersecurity, Environmental Justice, Logistics, and Housing and City Planning. While some people come into the challenge with friends, Sandoval said most teams form organically during an online networking meeting hosted by MIT.

    “We encourage people to pair up with others outside of their country and to form teams of different diverse backgrounds and ages,” Sandoval says. “We try to give people who are often not invited to the decision-making table the opportunity to be a policymaker, bringing in those with backgrounds in not only law, policy, or politics, but also medicine, and people who have careers in engineering or experience working in nonprofits.”

    Once an in-person event, the Policy Hackathon has gone through its own regeneration process these past three years, according to Sandoval. After going entirely online during the pandemic’s height, last year they successfully hosted the first hybrid version of the event, which served as their model again this year.

    “The hybrid version of the event gives us the opportunity to allow people to connect in a way that is lost if it is only online, while also keeping the wide range of accessibility, allowing people to join from anywhere in the world, regardless of nationality or income, to provide their input,” Sandoval says.

    For Swetha Tadisina, an undergraduate computer science major at Lafayette College and participant in the internet and cybersecurity category, the hackathon was a unique opportunity to meet and work with people much more advanced in their careers. “I was surprised how such a diverse team that had never met before was able to work so efficiently and creatively,” Tadisina says.

    Erika Spangler, a public high school teacher from Massachusetts and member of the environmental justice category’s winning team, says that while each member of “Team Slime Mold” came to the table with a different set of skills, they managed to be in sync from the start — even working across the nine-and-a-half-hour time difference the four-person team faced when working with policy advocate Shruti Nandy from Calcutta, India.

    “We divided the project into data, policy, and research and trusted each other’s expertise,” Spangler says, “Despite having separate areas of focus, we made sure to have regular check-ins to problem-solve and cross-pollinate ideas.”

    During the 48-hour period, her team proposed the creation of an algorithm to identify high-quality brownfields that could be cleaned up and used as sites for building renewable energy. Their corresponding policy sought to mandate additional requirements for renewable energy businesses seeking tax credits from the Inflation Reduction Act.

    “Their policy memo had the most in-depth technical assessment, including deep dives in a few key cities to show the impact of their proposed approach for site selection at a very granular level,” says Amanda Levin, director of policy analysis for the Natural Resources Defense Council (NRDC). Levin acted as both a judge and challenge provider for the environmental justice category.

    “They also presented their policy recommendations in the memo in a well-thought-out way, clearly noting the relevant actor,” she adds. This clarity around what can be done, and who would be responsible for those actions, is highly valuable for those in policy.”

    Levin says the NRDC, one of the largest environmental nonprofits in the United States, provided five “challenge questions,” making it clear that teams did not need to address all of them. She notes that this gave teams significant leeway, bringing a wide variety of recommendations to the table. 

    “As a challenge partner, the work put together by all the teams is already being used to help inform discussions about the implementation of the Inflation Reduction Act,” Levin says. “Being able to tap into the collective intelligence of the hackathon helped uncover new perspectives and policy solutions that can help make an impact in addressing the important policy challenges we face today.”

    While having partners with experience in data science and policy definitely helped, fellow Team Slime Mold member Sara Sheffels, a PhD candidate in MIT’s biomaterials program, says she was surprised how much her experiences outside of science and policy were relevant to the challenge: “My experience organizing MIT’s Graduate Student Union shaped my ideas about more meaningful community involvement in renewables projects on brownfields. It is not meaningful to merely educate people about the importance of renewables or ask them to sign off on a pre-planned project without addressing their other needs.”

    “I wanted to test my limits, gain exposure, and expand my world,” Tadisina adds. “The exposure, friendships, and experiences you gain in such a short period of time are incredible.”

    For Willy R. Vasquez, an electrical and computer engineering PhD student at the University of Texas, the hackathon is not to be missed. “If you’re interested in the intersection of tech, society, and policy, then this is a must-do experience.” More

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    Machinery of the state

    In Mai Hassan’s studies of Kenya, she documented the emergence of a sprawling administrative network officially billed as encouraging economic development, overseeing the population, and bolstering democracy. But Hassan’s field interviews and archival research revealed a more sinister purpose for the hundreds of administrative and security offices dotting the nation: “They were there to do the presidents’ bidding, which often involved coercing their own countrymen.”

    This research served as a catalyst for Hassan, who joined MIT as an associate professor of political science in July, to investigate what she calls the “politicized management of bureaucracy and the state.” She set out to “understand the motivations, capacities, and roles of people administering state programs and social functions,” she says. “I realized the state is not a faceless being, but instead comprised of bureaucrats carrying out functions on behalf of the state and the regime that runs it.”

    Today, Hassan’s portfolio encompasses not just the bureaucratic state but democratization efforts in Kenya and elsewhere in the East Africa region, including her native Sudan. Her research highlights the difficulties of democratization. “I’m finding that the conditions under which people come together for overthrowing an autocratic regime really matter, because those conditions may actually impede a nation from achieving democracy,” she says.

    A coordinated bureaucracy

    Hassan’s academic engagement with the state’s administrative machinery began during graduate school at Harvard University, where she earned her master’s and doctorate in government. While working with a community trash and sanitation program in some Kenyan Maasai communities, Hassan recalls “shepherding myself from office to office, meeting different bureaucrats to obtain the same approvals but for different jurisdictions.” The Kenyan state had recently set up hundreds of new local administrative units, motivated by what it claimed was the need for greater efficiency. But to Hassan’s eyes, “the administrative network was not well organized, seemed costly to maintain, and seemed to hinder — not bolster — development,” she says. What then, she wondered, was “the political logic behind such state restructuring?”

    Hassan began researching this bureaucratic transformation of Kenya, speaking with administrators in communities large and small who were charged with handling the business of the state. These studies yielded a wealth of findings for her dissertation, and for multiple journals.

    But upon finishing this tranche of research, Hassan realized that it was insufficient simply to study the structure of the state. “Understanding the role of new administrative structures for politics, development, and governance fundamentally requires that we understand who the government has put in charge of them,” she says. Among her insights:

    “The president’s office knows a lot of these administrators, and thinks about their strengths, limitations, and fit within a community,” says Hassan. Some administrators served the purposes of the central government by setting up water irrigation projects or building a new school. But in other villages, the state chose administrators who could act “much more coercively, ignoring development needs, throwing youth who supported the opposition into jail, and spending resources exclusively on policing.”

    Hassan’s work showed that in communities characterized by strong political opposition, “the local administration was always more coercive, regardless of an elected or autocratic president,” she says. Notably, the tenures of such officials proved shorter than those of their peers. “Once administrators get to know a community — going to church and the market with residents — it’s hard to coerce them,” explains Hassan.

    These short tenures come with costs, she notes: “Spending significant time in a station is useful for development, because you know exactly whom to hire if you want to build a school or get something done efficiently.” Politicizing these assignments undermines efforts at delivery of services and, more broadly, economic improvement nationwide. “Regimes that are more invested in retaining power must devote resources to establishing and maintaining control, resources that could otherwise be used for development and the welfare of citizens,” she says.

    Hassan wove together her research covering three presidents over a 50-year period, in the book, “Regime Threats and State Solutions: Bureaucratic Loyalty and Embeddedness in Kenya” (2020, Cambridge University Press), named a Foreign Affairs Best Book of 2020.

    Sudanese roots

    The role of the state in fulfilling the needs of its citizens has long fascinated Hassan. Her grandfather, who had served as Sudan’s ambassador to the USSR, talked to her about the advantages of a centralized government “that allocated resources to reduce inequality,” she says.

    Politics often dominated the conversation in gatherings of Hassan’s family and friends. Her parents immigrated to northern Virginia when she was very young, and many relatives joined them, part of a steady flow of Sudanese fleeing political turmoil and oppression.

    “A lot of people had expected more from the Sudanese state after independence and didn’t get it,” she says. “People had hopes for what the government could and should do.”

    Hassan’s Sudanese roots and ongoing connection to the Sudanese community have shaped her academic interests and goals. At the University of Virginia, she gravitated toward history and economics classes. But it was her time at the Ralph Bunche Summer institute that perhaps proved most pivotal in her journey. This five-week intensive program is offered by the American Political Science Association to introduce underrepresented undergraduate students to doctoral studies. “It was really compelling in this program to think rigorously about all the political ideas I’d heard as I was growing up, and find ways to challenge some assertions empirically,” she says.

    Regime change and civil society

    At Harvard, Hassan first set out to focus on Sudan for her doctoral program. “There wasn’t much scholarship on the country, and what there was lacked rigor,” she says. “That was something that needed to change.” But she decided to postpone this goal after realizing that she might be vulnerable as a student conducting field research there. She landed instead in Kenya, where she honed her interviewing and data collection skills.

    Today, empowered by her prior work, she has returned to Sudan. “I felt that the popular uprising in Sudan and ousting of the Islamist regime in 2019 should be documented and analyzed,” she says. “It was incredible that hundreds of thousands, if not millions, acted collectively to uproot a dictator, in the face of brutal violence from the state.”But “democracy is still uncertain there,” says Hassan. The broad coalition behind regime change “doesn’t know how to govern because different people and different sectors of society have different ideas about what democratic Sudan should look like,” she says. “Overthrowing an autocratic regime and having civil society come together to figure out what’s going to replace it require different things, and it’s unclear if a movement that accomplishes the first is well-suited to do the second.”

    Hassan believes that in order to create lasting democratization, “you need the hard work of building organizations, developing ways in which members learn to compromise among themselves, and make decisions and rules for how to move forward.”

    Hassan is enjoying the fall semester and teaching courses on autocracy and authoritarian regimes. She is excited as well about developing her work on African efforts at democratic mobilization in a political science department she describes as “policy-forward.”

    Over time, she hopes to connect with Institute scholars in the hard sciences to think about other challenges these nations are facing, such as climate change. “It’s really hot in Sudan, and it may be one of the first countries to become completely uninhabitable,” she says. “I’d like to explore strategies for growing crops differently or managing the exceedingly scarce resource of water, and figure out what kind of political discussions will be necessary to implement any changes. It is really critical to think about these problems in an interdisciplinary way.” More

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    Earth can regulate its own temperature over millennia, new study finds

    The Earth’s climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.

    Now, a study by MIT researchers in Science Advances confirms that the planet harbors a “stabilizing feedback” mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range.

    Just how does it accomplish this? A likely mechanism is “silicate weathering” — a geological process by which the slow and steady weathering of silicate rocks involves chemical reactions that ultimately draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks.

    Scientists have long suspected that silicate weathering plays a major role in regulating the Earth’s carbon cycle. The mechanism of silicate weathering could provide a geologically constant force in keeping carbon dioxide — and global temperatures — in check. But there’s never been direct evidence for the continual operation of such a feedback, until now.

    The new findings are based on a study of paleoclimate data that record changes in average global temperatures over the last 66 million years. The MIT team applied a mathematical analysis to see whether the data revealed any patterns characteristic of stabilizing phenomena that reined in global temperatures on a  geologic timescale.

    They found that indeed there appears to be a consistent pattern in which the Earth’s temperature swings are dampened over timescales of hundreds of thousands of years. The duration of this effect is similar to the timescales over which silicate weathering is predicted to act.

    The results are the first to use actual data to confirm the existence of a stabilizing feedback, the mechanism of which is likely silicate weathering. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.

    “On the one hand, it’s good because we know that today’s global warming will eventually be canceled out through this stabilizing feedback,” says Constantin Arnscheidt, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues.”

    The study is co-authored by Arnscheidt and Daniel Rothman, professor of geophysics at MIT.

    Stability in data

    Scientists have previously seen hints of a climate-stabilizing effect in the Earth’s carbon cycle: Chemical analyses of ancient rocks have shown that the flux of carbon in and out of Earth’s surface environment has remained relatively balanced, even through dramatic swings in global temperature. Furthermore, models of silicate weathering predict that the process should have some stabilizing effect on the global climate. And finally, the fact of the Earth’s enduring habitability points to some inherent, geologic check on extreme temperature swings.

    “You have a planet whose climate was subjected to so many dramatic external changes. Why did life survive all this time? One argument is that we need some sort of stabilizing mechanism to keep temperatures suitable for life,” Arnscheidt says. “But it’s never been demonstrated from data that such a mechanism has consistently controlled Earth’s climate.”

    Arnscheidt and Rothman sought to confirm whether a stabilizing feedback has indeed been at work, by looking at data of global temperature fluctuations through geologic history. They worked with a range of global temperature records compiled by other scientists, from the chemical composition of ancient marine fossils and shells, as well as preserved Antarctic ice cores.

    “This whole study is only possible because there have been great advances in improving the resolution of these deep-sea temperature records,” Arnscheidt notes. “Now we have data going back 66 million years, with data points at most thousands of years apart.”

    Speeding to a stop

    To the data, the team applied the mathematical theory of stochastic differential equations, which is commonly used to reveal patterns in widely fluctuating datasets.

    “We realized this theory makes predictions for what you would expect Earth’s temperature history to look like if there had been feedbacks acting on certain timescales,” Arnscheidt explains.

    Using this approach, the team analyzed the history of average global temperatures over the last 66 million years, considering the entire period over different timescales, such as tens of thousands of years versus hundreds of thousands, to see whether any patterns of stabilizing feedback emerged within each timescale.

    “To some extent, it’s like your car is speeding down the street, and when you put on the brakes, you slide for a long time before you stop,” Rothman says. “There’s a timescale over which frictional resistance, or a stabilizing feedback, kicks in, when the system returns to a steady state.”

    Without stabilizing feedbacks, fluctuations of global temperature should grow with timescale. But the team’s analysis revealed a regime in which fluctuations did not grow, implying that a stabilizing mechanism reigned in the climate before fluctuations grew too extreme. The timescale for this stabilizing effect — hundreds of thousands of years — coincides with what scientists predict for silicate weathering.

    Interestingly, Arnscheidt and Rothman found that on longer timescales, the data did not reveal any stabilizing feedbacks. That is, there doesn’t appear to be any recurring pull-back of global temperatures on timescales longer than a million years. Over these longer timescales, then, what has kept global temperatures in check?

    “There’s an idea that chance may have played a major role in determining why, after more than 3 billion years, life still exists,” Rothman offers.

    In other words, as the Earth’s temperatures fluctuate over longer stretches, these fluctuations may just happen to be small enough in the geologic sense, to be within a range that a stabilizing feedback, such as silicate weathering, could periodically keep the climate in check, and more to the point, within a habitable zone.

    “There are two camps: Some say random chance is a good enough explanation, and others say there must be a stabilizing feedback,” Arnscheidt says. “We’re able to show, directly from data, that the answer is probably somewhere in between. In other words, there was some stabilization, but pure luck likely also played a role in keeping Earth continuously habitable.”

    This research was supported, in part, by a MathWorks fellowship and the National Science Foundation. More

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    Keeping indoor humidity levels at a “sweet spot” may reduce spread of Covid-19

    We know proper indoor ventilation is key to reducing the spread of Covid-19. Now, a study by MIT researchers finds that indoor relative humidity may also influence transmission of the virus.

    Relative humidity is the amount of moisture in the air compared to the total moisture the air can hold at a given temperature before saturating and forming condensation.

    In a study appearing today in the Journal of the Royal Society Interface, the MIT team reports that maintaining an indoor relative humidity between 40 and 60 percent is associated with relatively lower rates of Covid-19 infections and deaths, while indoor conditions outside this range are associated with worse Covid-19 outcomes. To put this into perspective, most people are comfortable between 30 and 50 percent relative humidity, and an airplane cabin is at around 20 percent relative humidity.

    The findings are based on the team’s analysis of Covid-19 data combined with meteorological measurements from 121 countries, from January 2020 through August 2020. Their study suggests a strong connection between regional outbreaks and indoor relative humidity.

    In general, the researchers found that whenever a region experienced a rise in Covid-19 cases and deaths prevaccination, the estimated indoor relative humidity in that region, on average, was either lower than 40 percent or higher than 60 percent regardless of season. Nearly all regions in the study experienced fewer Covid-19 cases and deaths during periods when estimated indoor relative humidity was within a “sweet spot” between 40 and 60 percent.

    “There’s potentially a protective effect of this intermediate indoor relative humidity,” suggests lead author Connor Verheyen, a PhD student in medical engineering and medical physics in the Harvard-MIT Program in Health Sciences and Technology.

    “Indoor ventilation is still critical,” says co-author Lydia Bourouiba, director of the MIT Fluid Dynamics of Disease Transmission Laboratory and associate professor in the departments of Civil and Environmental Engineering and Mechanical Engineering, and at the Institute for Medical Engineering and Science at MIT. “However, we find that maintaining an indoor relative humidity in that sweet spot — of 40 to 60 percent — is associated with reduced Covid-19 cases and deaths.”

    Seasonal swing?

    Since the start of the Covid-19 pandemic, scientists have considered the possibility that the virus’ virulence swings with the seasons. Infections and associated deaths appear to rise in winter and ebb in summer. But studies looking to link the virus’ patterns to seasonal outdoor conditions have yielded mixed results.

    Verheyen and Bourouiba examined whether Covid-19 is influenced instead by indoor — rather than outdoor — conditions, and, specifically, relative humidity. After all, they note that most societies spend more than 90 percent of their time indoors, where the majority of viral transmission has been shown to occur. What’s more, indoor conditions can be quite different from outdoor conditions as a result of climate control systems, such as heaters that significantly dry out indoor air.

    Could indoor relative humidity have affected the spread and severity of Covid-19 around the world? And could it help explain the differences in health outcomes from region to region?

    Tracking humidity

    For answers, the team focused on the early period of the pandemic when vaccines were not yet available, reasoning that vaccinated populations would obscure the influence of any other factor such as indoor humidity. They gathered global Covid-19 data, including case counts and reported deaths, from January 2020 to August 2020,  and identified countries with at least 50 deaths, indicating at least one outbreak had occurred in those countries.

    In all, they focused on 121 countries where Covid-19 outbreaks occurred. For each country, they also tracked the local Covid-19 related policies, such as isolation, quarantine, and testing measures, and their statistical association with Covid-19 outcomes.

    For each day that Covid-19 data was available, they used meteorological data to calculate a country’s outdoor relative humidity. They then estimated the average indoor relative humidity, based on outdoor relative humidity and guidelines on temperature ranges for human comfort. For instance, guidelines report that humans are comfortable between 66 to 77 degrees Fahrenheit indoors. They also assumed that on average, most populations have the means to heat indoor spaces to comfortable temperatures. Finally, they also collected experimental data, which they used to validate their estimation approach.

    For every instance when outdoor temperatures were below the typical human comfort range, they assumed indoor spaces were heated to reach that comfort range. Based on the added heating, they calculated the associated drop in indoor relative humidity.

    In warmer times, both outdoor and indoor relative humidity for each country was about the same, but they quickly diverged in colder times. While outdoor humidity remained around 50 percent throughout the year, indoor relative humidity for countries in the Northern and Southern Hemispheres dropped below 40 percent in their respective colder periods, when Covid-19 cases and deaths also spiked in these regions.

    For countries in the tropics, relative humidity was about the same indoors and outdoors throughout the year, with a gradual rise indoors during the region’s summer season, when high outdoor humidity likely raised the indoor relative humidity over 60 percent. They found this rise mirrored the gradual increase in Covid-19 deaths in the tropics.

    “We saw more reported Covid-19 deaths on the low and high end of indoor relative humidity, and less in this sweet spot of 40 to 60 percent,” Verheyen says. “This intermediate relative humidity window is associated with a better outcome, meaning fewer deaths and a deceleration of the pandemic.”

    “We were very skeptical initially, especially as the Covid-19 data can be noisy and inconsistent,” Bourouiba says. “We thus were very thorough trying to poke holes in our own analysis, using a range of approaches to test the limits and robustness of the findings, including taking into account factors such as government intervention. Despite all our best efforts, we found that even when considering countries with very strong versus very weak Covid-19 mitigation policies, or wildly different outdoor conditions, indoor — rather than outdoor — relative humidity maintains an underlying strong and robust link with Covid-19 outcomes.”

    It’s still unclear how indoor relative humidity affects Covid-19 outcomes. The team’s follow-up studies suggest that pathogens may survive longer in respiratory droplets in both very dry and very humid conditions.

    “Our ongoing work shows that there are emerging hints of mechanistic links between these factors,” Bourouiba says. “For now however, we can say that indoor relative humidity emerges in a robust manner as another mitigation lever that organizations and individuals can monitor, adjust, and maintain in the optimal 40 to 60 percent range, in addition to proper ventillation.”

    This research was made possible, in part, by an MIT Alumni Class fund, the Richard and Susan Smith Family Foundation, the National Institutes of Health, and the National Science Foundation. More

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    in Environment

    Nonabah Lane, Navajo educator and environmental sustainability specialist with numerous ties to MIT, dies at 46

    Nonabah Lane, a Navajo educator and environmental sustainability specialist with numerous MIT ties to MIT, passed away in October. She was 46.

    Lane had recently been an MIT Media Lab Director’s Fellow; MIT Solve 2019 Indigenous Communities Fellow; Department of Urban Studies and Planning guest lecturer and community partner; community partner with the PKG Public Service Center, Terrascope, and D-Lab; and a speaker at this year’s MIT Energy Week.

    Lane was a passionate sustainability specialist with experience spearheading successful environmental civic science projects focused in agriculture, water science, and energy. Committed to mitigating water pollutants and environmental hazards in tribal communities, she held extensive knowledge of environmental policy and Indigenous water rights. 

    Lane’s clans were Ta’neezahnii (Tangled People), born for Tł’izíłání (Manygoats People), and her maternal grandfathers are the Kiiyaa’aanii (Towering House People), and paternal grandfathers are Bįįh Bitoo’nii (Deer Spring People).

    Lane was a member of the Navajo Nation, Nenahnezad Chapter. At Navajo Power, she worked as the lead developer for solar and energy storage projects to benefit tribal communities on the Navajo Nation and other tribal nations in New Mexico. Prior to joining Navajo Power, Lane co-founded Navajo Ethno-Agriculture, a farm that teaches Navajo culture through traditional farming and bilingual education. Lane also launched a campaign to partner with local Navajo schools and tribal colleges to create their own water-testing capabilities and translate data into information to local farmers.

    “I had the opportunity to collaborate closely with Nonabah on a range of initiatives she was championing on energy, food, justice, water, Indigenous leadership, youth STEM, and more. She was innovative, entrepreneurial, inclusive, heartfelt, and positively impacted MIT on every visit to campus. She articulated important things that needed saying and expanded people’s thinking constantly. We will all miss her insights and teamwork,” says Megan Smith ’86, SM ’88, MIT Corporation life member; third U.S. chief technology officer and assistant to the president in the Office of Science and Technology Policy; and founder and CEO of shift7.

    In March 2019, Lane and her family — parents Gloria and Harry and brother Bruce — welcomed students and staff of the MIT Terrascope first-year learning community to their farm, where they taught unique, hands-on lessons about traditional Diné farming and spirituality. She then continued to collaborate with Terrascope, helping staff and students develop community-based work with partners in Navajo Nation. 

    Terrascope associate director and lecturer Ari Epstein says, “Nonabah was an inspiring person and a remarkable collaborator; she had a talent for connecting and communicating across disciplinary, organizational, and cultural differences, and she was generous with her expertise and knowledge. We will miss her very much.”

    Lane came to MIT in May 2019 for the MIT Solve Indigenous Communities Fellowship and Solve at MIT event, representing Navajo Ethno-Agriculture with her mother, Gloria Lane, and brother, Bruce Lane, and later serving as a Fellow Leadership Group member. 

    “Nonabah was an incredible individual who worked tirelessly to better all of her communities, whether it was back home on the Navajo Nation, here at MIT Solve, or supporting her family and friends,” says Alex Amouyel, executive director of MIT Solve. “More than that, Nonabah was a passionate mentor and caring friend of so many, carefully tending the next generation of Indigenous innovators, entrepreneurs, and change-makers. Her loss will be felt deeply by the MIT community, and her legacy of heartfelt service will not be forgotten.”

    She continued to be heavily involved across the MIT campus — named as a 2019 Media Lab Director’s Fellow, leading a workshop at the 2020 MIT Media Lab Festival of Learning on modernizing Navajo foods using traditional food science and cultural narrative, speaking at the 2022 MIT Energy Conference “Accelerating the Clean Energy Transition,” and taking part in the MIT Center for Bits and Atoms (CBA) innovation weekly co-working groups for Covid-response related innovations. 

    “My CBA colleagues and I enjoyed working with Nonabah on rapid-prototyping for the Covid response, on expanding access to digital fabrication, and on ambitious proposals for connecting emerging technology with Indigenous knowledge,” says Professor Neil Gershenfeld, director, MIT Center for Bits and Atoms.

    Nonabah also guest lectured for the MIT Department of Urban Studies and Planning’s Indigenous Environmental Planning class in Spring 2022. Professors Lawrence Susskind and Gabriella Carolini and teaching assistant Dení López led the class in cooperation with Elizabeth Rule, Chickasaw Nation member and professor at American University. 

    Carolini shares, on behalf of Susskind and the class, “During this time, our teaching team and students from a broad range of fields at MIT had the deep honor of learning from and with the inimitable Nonabah Lane. Nonabah was a dedicated and critical partner to our class, representing in this instance Navajo Power — but of course, also so much more. Her broad experiences and knowledge — working with fellow Navajo members on energy and agriculture sovereignty, as well as in advancing entrepreneurship and innovation — reflected the urgency Nonabah saw in meeting the challenges and opportunities for sustainable and equitable futures in Navajo nation and beyond. She was a pure life force, running on all fires, and brought to our class a dedicated drive to educate, learn, and extend our reference points beyond current knowledge frontiers.” 

    Three MIT students — junior Isabella Gandara, Alexander Gerszten ’22, and Paul Picciano MS ’22 — who worked closely with Lane on a project with Navajo Power, recalled how she shared herself with them in so many ways, through her truly exceptional work ethic, stories about herself and her family, and the care and thought that she put into her ventures. They noted there was always something new to feel inspired by when in her presence. 

    “The PKG Public Service Center mourns the passing of Nonabah Lane. Navajo Ethno-Agriculture is a valued PKG Center partner that offers MIT undergraduate students the opportunity to support community-led projects with the Diné Community on Navajo Nation. Nonabah inspired students to examine broad social and technical issues that impact Indigenous communities in Navajo Nation and beyond, in many cases leaving an indelible mark on their personal and professional paths,” says Jill S. Bassett, associate dean and director of the PKG Public Service Center.

    Lane was a Sequoyah Fellow of the American Indian Science and Engineering Society (AISES) and remained actively engaged in the AISES community by mentoring young people interested in the fields of science, engineering, agriculture, and energy. Over the years, Lane collaborated with leaders across tribal lands and beyond on projects related to agriculture, energy, sustainable chemicals, and finance. Lane had an enormous positive impact on many through her accomplishments and also the countless meaningful connections she helped to form among people in diverse fields.

    Donations may be made to a memorial fund organized by Navajo Power, PBC in honor of Nonabah Lane, in support of Navajo Ethno-Agriculture, the Native American nonprofit she co-founded and cared deeply for. More

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    in Environment

    MIT PhD students shed light on important water and food research

    One glance at the news lately will reveal countless headlines on the dire state of global water and food security. Pollution, supply chain disruptions, and the war in Ukraine are all threatening water and food systems, compounding climate change impacts from heat waves, drought, floods, and wildfires.

    Every year, MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) offers fellowships to outstanding MIT graduate students who are working on innovative ways to secure water and food supplies in light of these urgent worldwide threats. J-WAFS announced this year’s fellowship recipients last April. Aditya Ghodgaonkar and Devashish Gokhale were awarded Rasikbhai L. Meswani Fellowships for Water Solutions, which are made possible by a generous gift from Elina and Nikhil Meswani and family. James Zhang, Katharina Fransen, and Linzixuan (Rhoda) Zhang were awarded J-WAFS Fellowships for Water and Food Solutions. The J-WAFS Fellowship for Water and Food Solutions is funded in part by J-WAFS Research Affiliate companies: Xylem, Inc., a water technology company, and GoAigua, a company leading the digital transformation of the water industry.

    The five fellows were each awarded a stipend and full tuition for one semester. They also benefit from mentorship, networking connections, and opportunities to showcase their research.

    “This year’s cohort of J-WAFS fellows show an indefatigable drive to explore, create, and push back boundaries,” says John H. Lienhard, director of J-WAFS. “Their passion and determination to create positive change for humanity are evident in these unique video portraits, which describe their solutions-oriented research in water and food,” Lienhard adds.

    J-WAFS funder Community Jameel recently commissioned video portraitures of each student that highlight their work and their inspiration to solve challenges in water and food. More about each J-WAFS fellow and their research follows.

    Play video

    Katharina Fransen

    In Professor Bradley Olsen’s lab in the Department of Chemical Engineering, Katharina Fransen works to develop biologically-based, biodegradable plastics which can be used for food packing that won’t pollute the environment. Fransen, a third-year PhD student, is motivated by the challenge of protecting the most vulnerable global communities from waste generated by the materials that are essential to connecting them to the global food supply. “We can’t ensure that all of our plastic waste gets recycled or reused, and so we want to make sure that if it does escape into the environment it can degrade, and that’s kind of where a lot of my research really comes in,” says Fransen. Most of her work involves creating polymers, or “really long chains of chemicals,” kind of like the paper rings a lot of us looped into chains as kids, Fransen explains. The polymers are optimized for food packaging applications to keep food fresher for longer, preventing food waste. Fransen says she finds the work “really interesting from the scientific perspective as well as from the idea that [she’s] going to make the world a little better with these new materials.” She adds, “I think it is both really fulfilling and really exciting and engaging.”

    Play video

    Aditya Ghodgaonkar

    “When I went to Kenya this past spring break, I had an opportunity to meet a lot of farmers and talk to them about what kind of maintenance issues they face,” says Aditya Ghodgaonkar, PhD candidate in the Department of Mechanical Engineering. Ghodgaonkar works with Associate Professor Amos Winter in the Global Engineering and Research (GEAR) Lab, where he designs hydraulic components for drip irrigation systems to make them water-efficient, off-grid, inexpensive, and low-maintenance. On his trip to Kenya, Ghodgaonkar gained firsthand knowledge from farmers about a common problem they encounter: clogging of drip irrigation emitters. He learned that clogging can be an expensive technical challenge to diagnose, mitigate, and resolve. He decided to focus his attention on designing emitters that are resistant to clogging, testing with sand and passive hydrodynamic filtration back in the lab at MIT. “I got into this from an academic standpoint,” says Ghodgaonkar. “It is only once I started working on the emitters, spoke with industrial partners that make these emitters, spoke with farmers, that I really truly appreciated the impact of what we’re doing.”

    Play video

    Devashish Gokhale

    Devashish Gokhale is a PhD student advised by Professor Patrick Doyle in the Department of Chemical Engineering. Gokhale’s commitment to global water security stems from his childhood in Pune, India, where both flooding and drought can occur depending on the time of year. “I’ve had these experiences where there’s been too much water and also too little water” he recalls. At MIT, Gokhale is developing cost-effective, sustainable, and reusable materials for water treatment with a focus on the elimination of emerging contaminants and low-concentration pollutants like heavy metals. Specifically, he works on making and optimizing polymeric hydrogel microparticles that can absorb micropollutants. “I know how important it is to do something which is not just scientifically interesting, but something which is impactful in a real way,” says Gokhale. Before starting a research project he asks himself, “are people going to be able to afford this? Is it really going to reach the people who need it the most?” Adding these constraints in the beginning of the research process sometimes makes the problem more difficult to solve, but Gokhale notes that in the end, the solution is much more promising.

    Play video

    James Zhang

    “We don’t really think much about it, it’s transparent, odorless, we just turn on our sink in many parts of the world and it just flows through,” says James Zhang when talking about water. Yet he notes that “many other parts of the world face water scarcity and this will only get worse due to global climate change.” A PhD student in the Department of Mechanical Engineering, Zhang works in the Nano Engineering Laboratory with Professor Gang Chen. Zhang is working on a technology that uses light-induced evaporation to clean water. He is currently investigating the fundamental properties of how light at different wavelengths interacts with liquids at the surface, particularly with brackish water surfaces. With strong theoretical and experimental components, his research could lead to innovations in desalinating water at high energy efficiencies. Zhang hopes that the technology can one day “produce lots of clean water for communities around the world that currently don’t have access to fresh water,” and create a new appreciation for this common liquid that many of us might not think about on a day-to-day basis.

    Play video

    Linzixuan (Rhoda) Zhang

    “Around the world there are about 2 billion people currently suffering from micronutrient deficiency because they do not have access to very healthy, very fresh food,” says chemical engineering PhD candidate Linzixuan (Rhoda) Zhang. This fact led Zhang to develop a micronutrient delivery platform that fortifies foods with essential vitamins and nutrients. With her advisors, Professor Robert Langer and Research Scientist Ana Jaklenec, Zhang brings biomedical engineering approaches to global health issues. Zhang says that “one of the most serious problems is vitamin A deficiency, because vitamin A is not very stable.” She goes on to explain that although vitamin A is present in different vegetables, when the vegetables are cooked, vitamin A can easily degrade. Zhang helped develop a group of biodegradable polymers that can stabilize micronutrients under cooking and storage conditions. With this technology, vitamin A, for example, could be encapsulated and effectively stabilized under boiling water. The platform has also shown efficient release in a simulation of the stomach environment. Zhang says it is the “little, tiny steps every day that are pushing us forward to the final impactful product.” More