Sojourner sent back photos of the Martian surface during the summer of 1997. I was not alone. The servers at NASA’s Jet Propulsion Lab slowed to a crawl when they got more than 47 million hits (a record number!) from people attempting to download those early images of the Red Planet. To be fair, it was the late 1990s, the Internet was still young, and most people were using dial-up modems. By the end of the 83-day mission, Sojourner had sent back 550 photos and performed more than 15 chemical analyses of Martian rocks and soil. Sojourner, of course, remains on Mars. Pictured here is Marie Curie, its twin. Functionally identical, either one of the rovers could have made the voyage to Mars, but one of them was bound to become the famous face of the mission, while the other was destined to be left behind in obscurity. Did I write this piece because I feel a little bad for Marie Curie? Maybe. But it also gave me a chance to revisit this pioneering Mars mission, which established that robots could effectively explore the surface of planets and captivate the public imagination. Sojourner’s sojourn on Mars On 4 July 1997, the Mars Pathfinder parachuted through the Martian atmosphere and bounced about 15 times on glorified airbags before finally coming to a rest. The lander, renamed the Carl Sagan Memorial Station, carried precious cargo stowed inside. The next day, after the airbags retracted, the solar-powered Sojourner eased its way down the ramp, the first human-made vehicle to roll around on the surface of another planet. (It wasn’t the first extraterrestrial body, though. The Soviet Lunokhod rovers conducted two successful missions on the moon in 1970 and 1973. The Soviets had also landed a rover on Mars back in 1971, but communication was lost before the PROP-M ever deployed.) This giant sandbox at JPL provided Marie Curie with an approximation of Martian terrain. Mike Nelson/AFP/Getty Images Sojourner was equipped with three low-resolution cameras (two on the front for black-and-white images and a color camera on the rear), a laser hazard–avoidance system, an alpha-proton X-ray spectrometer, experiments for testing wheel abrasion and material adherence, and several accelerometers. The robot also demonstrated the value of the six-wheeled “rocker-bogie” suspension system that became NASA’s go-to design for all later Mars rovers. Sojourner never roamed more than about 12 meters from the lander due to the limited range of its radio. Pathfinder had landed in Ares Vallis, an assumed ancient floodplain chosen because of the wide variety of rocks present. Scientists hoped to confirm the past existence of water on the surface of Mars. Sojourner did discover rounded pebbles that suggested running water, and later missions confirmed it. A highlight of Sojourner’s 83-day mission on Mars was its encounter with a rock nicknamed Barnacle Bill [to the rover’s left]. JPL/NASA Sojourner rolled forward 36 centimeters and encountered a rock, dubbed Barnacle Bill due to its rough surface. The rover spent about 10 hours analyzing the rock, using its spectrometer to determine the elemental composition. Over the next few weeks, while the lander collected atmospheric information and took photos, the rover studied rocks in detail and tested the Martian soil. Marie Curie’s sojourn…in a JPL sandbox Meanwhile back on Earth, engineers at JPL used Marie Curie to mimic Sojourner’s movements in a Mars-like setting. During the original design and testing of the rovers, the team had set up giant sandboxes, each holding thousands of kilograms of playground sand, in the Space Flight Operations Facility at JPL. They exhaustively practiced the remote operation of Sojourner, including an 11-minute delay in communications between Mars and Earth. (The actual delay can vary from 7 to 20 minutes.) Even after Sojourner landed, Marie Curie continued to help them strategize. Initially, Sojourner was remotely operated from Earth, which was tricky given the lengthy communication delay. Mike Nelson/AFP/Getty Images Sojourner was maneuvered by an Earth-based operator wearing 3D goggles and using a funky input device called a Spaceball 2003. Images pieced together from both the lander and the rover guided the operator. It was like a very, very slow video game—the rover sometimes moved only a few centimeters a day. NASA then turned on Sojourner’s hazard-avoidance system, which allowed the rover some autonomy to explore its world. A human would suggest a path for that day’s exploration, and then the rover had to autonomously avoid any obstacles in its way, such as a big rock, a cliff, or a steep slope. Sojourner to operate for a week. But the little rover that could kept chugging along for 83 Martian days before NASA finally lost contact, on 7 October 1997. The lander had conked out on 27 September. In all, the mission collected 1.2 gigabytes of data (which at the time was a lot) and sent back 10,000 images of the planet’s surface. Marie Curie with the hopes of sending it on another mission to Mars. For a while, it was slated to be part of the Mars 2001 set of missions, but that didn’t happen. In 2015, JPL transferred the rover to the Smithsonian’s National Air and Space Museum. When NASA Embraced Faster, Better, Cheaper The Pathfinder mission was the second one in NASA administrator Daniel S. Goldin’s Discovery Program, which embodied his “faster, better, cheaper” philosophy of making NASA more nimble and efficient. (The first Discovery mission was to the asteroid Eros.) In the financial climate of the early 1990s, the space agency couldn’t risk a billion-dollar loss if a major mission failed. Goldin opted for smaller projects; the Pathfinder mission’s overall budget, including flight and operations, was capped at US $300 million. RELATED: How NASA Built Its Mars Rovers In his 2014 book Curiosity: An Inside Look at the Mars Rover Mission and the People Who Made It Happen (Prometheus), science writer Rod Pyle interviews Rob Manning, chief engineer for the Pathfinder mission and subsequent Mars rovers. Manning recalled that one of the best things about the mission was its relatively minimal requirements. The team was responsible for landing on Mars, delivering the rover, and transmitting images—technically challenging, to be sure, but beyond that the team had no constraints. Sojourner was succeeded by the rovers Spirit, Opportunity, and Curiosity. Shown here are four mission spares, including Marie Curie [foreground]. JPL-Caltech/NASA Sojourner’s electronics warm enough to operate were leftover spares from the Galileo mission to Jupiter, so they were “free.” Pathfinder mission successful but it captured the hearts of Americans and reinvigorated an interest in exploring Mars. In the process, it set the foundation for the future missions that allowed the rovers Spirit, Opportunity, and Curiosity (which, incredibly, is still operating nearly 13 years after it landed) to explore even more of the Red Planet. How the rovers Sojourner and Marie Curie got their names To name its first Mars rovers, NASA launched a student contest in March 1994, with the specific guidance of choosing a “heroine.” Entry essays were judged on their quality and creativity, the appropriateness of the name for a rover, and the student’s knowledge of the woman to be honored as well as the mission’s goals. Students from all over the world entered. Sojourner Truth, while 18-year-old Deepti Rohatgi of Rockville, Md., came in second for hers on Marie Curie. Truth was a Black woman born into slavery at the end of the 18th century. She escaped with her infant daughter and two years later won freedom for her son through legal action. She became a vocal advocate for civil rights, women’s rights, and alcohol temperance. Curie was a Polish-French physicist and chemist famous for her studies of radioactivity, a term she coined. She was the first woman to win a Nobel Prize, as well as the first person to win a second Nobel. Nancy Grace Roman, the space agency’s first chief of astronomy. In May 2020, NASA announced it would name the Wide Field Infrared Survey Telescope after Roman; the space telescope is set to launch as early as October 2026, although the Trump administration has repeatedly said it wants to cancel the project. A Trillion Rogue Planets and Not One Sun to Shine on Them its naming policy in December 2022 after allegations came to light that James Webb, for whom the James Webb Space Telescope is named, had fired LGBTQ+ employees at NASA and, before that, the State Department. A NASA investigation couldn’t substantiate the allegations, and so the telescope retained Webb’s name. But the bar is now much higher for NASA projects to memorialize anyone, deserving or otherwise. (The agency did allow the hopping lunar robot IM-2 Micro Nova Hopper, built by Intuitive Machines, to be named for computer-software pioneer Grace Hopper.) Marie Curie and Sojourner will remain part of a rarefied clique. Sojourner, inducted into the Robot Hall of Fame in 2003, will always be the celebrity of the pair. And Marie Curie will always remain on the sidelines. But think about it this way: Marie Curie is now on exhibit at one of the most popular museums in the world, where millions of visitors can see the rover up close. That’s not too shabby a legacy either. Part of a continuing series looking at historical artifacts that embrace the boundless potential of technology. An abridged version of this article appears in the June 2025 print issue. References Curator Matthew Shindell of the National Air and Space Museum first suggested I feature Marie Curie. I found additional information from the museum’s collections website, an article by David Kindy in Smithsonian magazine, and the book After Sputnik: 50 Years of the Space Age (Smithsonian Books/HarperCollins, 2007) by Smithsonian curator Martin Collins. NASA has numerous resources documenting the Mars Pathfinder mission, such as the mission website, fact sheet, and many lovely photos (including some of Barnacle Bill and a composite of Marie Curie during a prelaunch test). Curiosity: An Inside Look at the Mars Rover Mission and the People Who Made It Happen (Prometheus, 2014) by Rod Pyle and Roving Mars: Spirit, Opportunity, and the Exploration of the Red Planet (Hyperion, 2005) by planetary scientist Steve Squyres are both about later Mars missions and their rovers, but they include foundational information about Sojourner.

In the late 1970s, a time when 8-bit processors were state of the art and CMOS was the underdog of semiconductor technology, engineers at AT&T’s Bell Labs took a bold leap into the future. They made a high-stakes bet to outpace IBM, Intel, and other competitors in chip performance by combining cutting-edge 3.5-micron CMOS fabrication with a novel 32-bit processor architecture. Although their creation—the Bellmac-32 microprocessor—never achieved the commercial fame of earlier ones such as Intel’s 4004 (released in 1971), its influence has proven far more enduring. Virtually every chip in smartphones, laptops, and tablets today relies on the complementary metal-oxide semiconductor principles that the Bellmac-32 pioneered. As the 1980s approached, AT&T was grappling with transformation. For decades, the telecom giant—nicknamed “Ma Bell”—had dominated American voice communications, with its Western Electric subsidiary manufacturing nearly every telephone found in U.S. homes and offices. The U.S. federal government was pressing for antitrust-driven divestiture, but AT&T was granted an opening to expand into computing. With computing firms already entrenched in the market, AT&T couldn’t afford to play catch-up; its strategy was to leap ahead, and the Bellmac-32 was its springboard. The Bellmac-32 chip series has now been honored with an IEEE Milestone. Dedication ceremonies are slated to be held this year at the Nokia Bell Labs’ campus in Murray Hill, N.J., and at the Computer History Museum in Mountain View, Calif. A chip like no other Rather than emulate the industry standard of 8-bit chips, AT&T executives challenged their Bell Labs engineers to deliver something revolutionary: the first commercially viable microprocessor capable of moving 32 bits in one clock cycle. It would require not just a new chip but also an entirely novel architecture—one that could handle telecommunications switching and serve as the backbone for future computing systems. “We weren’t just building a faster chip,” says Michael Condry, who led the architecture team at Bell Labs’ Holmdel facility in New Jersey. “We were trying to design something that could carry both voice and computation into the future.” This configuration of the Bellmac-32 microprocessor had an integrated memory management unit optimized for Unix-like operating systems.AT&T Archives and History Center At the time, CMOS technology was seen as a promising—but risky—alternative to the NMOS and PMOS designs then in use. NMOS chips, which relied solely on N-type transistors, were fast but power-hungry. PMOS chips, which depend on the movement of positively-charged holes, were too slow. CMOS, with its hybrid design, offered the potential for both speed and energy savings. The benefits were so compelling that the industry soon saw that the need for double the number of transistors (NMOS and PMOS for each gate) was worth the tradeoff. As transistor sizes shrank along with the rapid advancement of semiconductor technology described by Moore’s Law, the cost of doubling up the transistor density soon became manageable and eventually became negligible. But when Bell Labs took its high-stakes gamble, large-scale CMOS fabrication was still unproven and looked to be comparatively costly. That didn’t deter Bell Labs. By tapping expertise from its campuses in Holmdel and Murray Hill as well as in Naperville, Ill., the company assembled a dream team of semiconductor engineers. The team included Condry; Sung-Mo “Steve” Kang, a rising star in chip design; Victor Huang, another microprocessor chip designer, and dozens of AT&T Bell Labs employees. They set out in 1978 to master a new CMOS process and create a 32-bit microprocessor from scratch. Designing the architecture The architecture group led by Condry, an IEEE Life Fellow who would later become Intel’s CTO, focused on building a system that would natively support the Unix operating system and the C programming language. Both were in their infancy but destined for dominance. To cope with the era’s memory limitations—kilobytes were precious—they introduced a complex instruction set that required fewer steps to carry out and could be executed in a single clock cycle. The engineers also built the chip to support the VersaModule Eurocard (VME) parallel bus, enabling distributed computing so several nodes could handle data processing in parallel. Making the chip VME-enabled also allowed it to be used for real-time control. The group wrote its own version of Unix, with real-time capabilities to ensure that the new chip design was compatible with industrial automation and similar applications. The Bell Labs engineers also invented domino logic, which ramped up processing speed by reducing delays in complex logic gates. Additional testing and verification techniques were developed and introduced via the Bellmac-32 Module, a sophisticated multi-chipset verification and testing project led by Huang that allowed the complex chip fabrication to have zero or near-zero errors. This was the first of its kind in VLSI testing. The Bell Labs engineers’ systematic plan for double- and triple-checking their colleagues’ work ultimately made the total design of the multiple chipset family work together seamlessly as a complete microcomputer system. Then came the hardest part: actually building the chip. Floor maps and colored pencils “The technology for layout, testing, and high-yield fabrication just wasn’t there,” recalls Kang, an IEEE Life Fellow who later became president of the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, South Korea. With no CAD tools available for full-chip verification, Kang says, the team resorted to printing oversize Calcomp plots. The schematics showed how the transistors, circuit lines, and interconnects should be arranged inside the chip to provide the desired outputs. The team assembled them on the floor with adhesive tape to create a massive square map more than 6 meters on a side. Kang and his colleagues traced every circuit by hand with colored pencils, searching for breaks, overlaps, or mishandled interconnects. Getting it made Once the physical design was locked in, the team faced another obstacle: manufacturing. The chips were fabricated at a Western Electric facility in Allentown, Pa., but Kang recalls that the yield rates (the percentage of chips on a silicon wafer that meet performance and quality standards) were dismal. To address that, Kang and his colleagues drove from New Jersey to the plant each day, rolled up their sleeves, and did whatever it took, including sweeping floors and calibrating test equipment, to build camaraderie and instill confidence that the most complicated product the plant workers had ever attempted to produce could indeed be made there. “We weren’t just building a faster chip. We were trying to design something that could carry both voice and computation into the future.” —Michael Condry, Bellmac-32 architecture team lead “The team-building worked out well,” Kang says. “After several months, Western Electric was able to produce more than the required number of good chips.” The first version of the Bellmac-32, which was ready by 1980, fell short of expectations. Instead of hitting a 4-megahertz performance target, it ran at just 2 MHz. The engineers discovered that the state-of-the-art Takeda Riken testing equipment they were using was flawed, with transmission-line effects between the probe and the test head leading to inaccurate measurements, so they worked with a Takeda Riken team to develop correction tables that rectified the measurement errors. The second generation of Bellmac chips had clock speeds that exceeded 6.2 MHz, sometimes reaching 9. That was blazing fast for its time. The 16-bit Intel 8008 processor inside IBM’s original PC released in 1981 ran at 4.77 MHz. Why Bellmac-32 didn’t go mainstream Despite its technical promise, the Bellmac-32 did not find wide commercial use. According to Condry, AT&T’s pivot toward acquiring equipment manufacturer NCR, which it began eyeing in the late 1980s, meant the company chose to back a different line of chips. But by then, the Bellmac-32’s legacy was already growing. “Before Bellmac-32, NMOS was dominant,” Condry says. “But CMOS changed the market because it was shown to be a more effective implementation in the fab.” In time, that realization reshaped the semiconductor landscape. CMOS would become the foundation for modern microprocessors, powering the digital revolution in desktops, smartphones, and more. The audacity of Bell Labs’ bet—to take an untested fabrication process and leapfrog an entire generation of chip architecture—stands as a landmark moment in technological history. As Kang puts it: “We were on the frontier of what was possible. We didn’t just follow the path—we made a new one.” Huang, an IEEE Life Fellow who later became deputy director of the Institute of Microelectronics, Singapore, adds: “This included not only chip architecture and design, but also large-scale chip verification—with CAD but without today’s digital simulation tools or even breadboarding [which is the standard method for checking whether a circuit design for an electronic system that uses chips works before making permanent connections by soldering the circuit elements together].” Condry, Kang, and Huang look back fondly on that period and express their admiration for the many AT&T employees whose skill and dedication made the Bellmac-32 chip series possible. Administered by the IEEE History Center and supported by donors, the Milestone program recognizes outstanding technical developments around the world. The IEEE North Jersey Section sponsored the nomination.

Humans are messy. We spill drinks, smudge screens, and bring our electronic devices into countless sticky situations. As anyone who has accidentally dropped their phone into a toilet or pool knows, moisture poses a particular problem. And it’s not a new one: From early telephones to modern cellphones, everyday liquids have frequently conflicted with devices that must stay dry. Consumers often take the blame when leaks and spills inevitably occur. Rachel Plotnick, an associate professor of cinema and media studies at Indiana University Bloomington, studies the relationship between technology and society. Last year, she spoke to IEEE Spectrum about her research on how people interact with buttons and tactile controls. In her new book, License to Spill: Where Dry Devices Meet Liquid Lives (The MIT Press, 2025), Plotnick explores the dynamic between everyday wetness and media devices through historical and contemporary examples, including cameras, vinyl records, and laptops. This adapted excerpt looks back at analog telephones of the 1910s through 1930s, the common practices that interrupted service, and the “trouble men” who were sent to repair phones and reform messy users. Boston Daily Globe in 1908 recounted, for instance, how a mother only learned her lesson about her baby’s cord chewing when the baby received a shock—or “got stung”—and the phone service went out. These youthful oral fixations rarely caused harm to the chewer, but were “injurious” to the telephone cord. License to Spill is Rachel Plotnick’s second book. Her first, Power Button: A History of Pleasure, Panic, and the Politics of Pushing (The MIT Press, 2018), explores the history and politics of push buttons. The MIT Press Telephony. Painters washed ceilings, which dripped; telephones sat near windows during storms; phone cords came in contact with moist radiators. A telephone chief operator who handled service complaints recounted that “a frequent combination in interior decoration is the canary bird and desk telephone occupying the same table. The canary bird includes the telephone in his morning bath,” thus leading to out-of-order service calls. housewife” who damaged wiring by scrubbing her telephone with water or cleaning fluid, and men in offices who dangerously propped their wet umbrellas against the wire. Wetness lurked everywhere in people’s spaces and habits; phone companies argued that one could hardly expect proper service under such circumstances—especially if users didn’t learn to accommodate the phone’s need for dryness. This differing appraisal of liquids caused problems when telephone customers expected service that would not falter and directed outrage at their provider when outages did occur. Consumers even sometimes admitted to swearing at the telephone receiver and haranguing operators. Telephone company employees, meanwhile, faced intense scrutiny and pressure to tend to telephone infrastructures. “Trouble” took two forms, then, in dealing with customers’ frustration over outages and in dealing with the damage from the wetness itself. The Original Troubleshooters Telephone breakdowns required determinations about the outage’s source. “Trouble men” and “trouble departments” hunted down the probable cause of the damage, which meant sussing out babies, sponges, damp locations, spills, and open windows. If customers wanted to lay blame at workers’ feet in these moments, then repairers labeled customers as abusers of the phone cord. One author attributed at least 50 percent of telephone trouble to cases where “someone has been careless or neglectful.” Trouble men employed medical metaphors to describe their work, as in “he is a physician, and he makes the ills that the telephone is heir to his life study.” Serge Bloch Even if a consumer knew the cord had gotten wet, they didn’t necessarily blame it as the cause of the outage. The repairer often used this as an opportunity to properly socialize the user about wetness and inappropriate telephone treatment. These conversations didn’t always go well: A 1918 article in Popular Science Monthly described an explosive argument between an infuriated woman and a phone company employee over a baby’s cord habits. The permissive mother and teething child had become emblematic of misuse, a photograph of them appearing in Bell Telephone News in 1917 as evidence of common trouble that a telephone (and its repairer) might encounter. However, no one blamed the baby; telephone workers unfailingly held mothers responsible as “bad” users. Teething babies and the mothers that let them play with phone cords were often blamed for telephone troubles. The Telephone Review/License to Spill Armed with such a tool, repairers glorified their own expertise. One wire chief was celebrated as the “original ‘find-out artist’” who could determine a telephone’s underlying troubles even in tricky cases. Telephone company employees leveraged themselves as experts who could attribute wetness’s causes to—in their estimation—uneducated (and even dimwitted) customers, who were often female. Women were often the earliest and most engaged phone users, adopting the device as a key mechanism for social relations, and so they became an easy target. Cost of Wet Phone Cord Repairs Though the phone industry and repairers were often framed as heroes, troubleshooting took its toll on overextended phone workers, and companies suffered a financial burden from repairs. One estimate by the American Telephone and Telegraph Company found that each time a company “clear[ed] wet cord trouble,” it cost a dollar. Phone companies portrayed the telephone as a fragile device that could be easily damaged by everyday life, aiming to make the subscriber a proactively “dry” and compliant user. Everyday sources of wetness, including mops and mustard, could cause hours of phone interruption. Telephony/License to Spill Moisture-Proofing Telephone Cords Although telephone companies put significant effort into reforming their subscribers, the increasing pervasiveness of telephony began to conflict with these abstinent aims. Thus, a new technological solution emerged that put the burden on moisture-proofing the wire. The Stromberg-Carlson Telephone Manufacturing Co. of Rochester, N.Y., began producing copper wire that featured an insulating enamel, two layers of silk, the company’s moisture-proof compound, and a layer of cotton. Called Duratex, the cord withstood a test in which the manufacturer submerged it in water for 48 hours. In its advertising, Stromberg-Carlson warned that many traditional cords—even if they seemed to dry out after wetting—had sustained interior damage so “gradual that it is seldom noticed until the subscriber complains of service.” Serge Bloch The Pickwick Papers, with his many layers of clothing. The product’s hardiness would allow the desk telephone to “withstand any climate,” even one hostile to communication technology. This subtle change meant that the burden to adapt fell to the device rather than the user. As telephone wires began to “penetrate everywhere,” they were imagined as fostering constant and unimpeded connectivity that not even saliva or a spilled drink could interrupt. The move to cord protection was not accompanied by a great deal of fanfare, however. As part of telephone infrastructure, cords faded into the background of conversations. Excerpted from License to Spill by Rachel Plotnick. Reprinted with permission from The MIT Press. Copyright 2025.

At an event in Dortmund, Germany today, Amazon announced a new robotic system called Vulcan, which the company is calling “its first robotic system with a genuine sense of touch—designed to transform how robots interact with the physical world.” In the short to medium term, the physical world that Amazon is most concerned with is its warehouses, and Vulcan is designed to assist (or take over, depending on your perspective) with stowing and picking items in its mobile robotic inventory system. Related: Amazon’s Vulcan Robots Are Mastering Picking Packages In two upcoming papers in IEEE Transactions on Robotics, Amazon researchers describe how both the stowing and picking side of the system operates. We covered stowing in detail a couple of years ago, when we spoke with Aaron Parness, the director of applied science at Amazon Robotics. Parness and his team have made a lot of progress on stowing since then, improving speed and reliability over more than 500,000 stows in operational warehouses to the point where the average stowing robot is now slightly faster than the average stowing human. We spoke with Parness to get an update on stowing, as well as an in-depth look at how Vulcan handles picking, which you can find in this separate article. It’s a much different problem, and well worth a read. Optimizing Amazon’s Stowing Process Stowing is the process by which Amazon brings products into its warehouses and adds them to its inventory so that you can order them. Not surprisingly, Amazon has gone to extreme lengths to optimize this process to maximize efficiency in both space and time. Human stowers are presented with a mobile robotic pod full of fabric cubbies (bins) with elastic bands across the front of them to keep stuff from falling out. The human’s job is to find a promising space in a bin, pull the plastic band aside, and stuff the thing into that space. The item’s new home is recorded in Amazon’s system, the pod then drives back into the warehouse, and the next pod comes along, ready for the next item. Different manipulation tools are used to interact with human-optimized bins.Amazon The new paper on stowing includes some interesting numbers about Amazon’s inventory-handling process that helps put the scale of the problem in perspective. More than 14 billion items are stowed by hand every year at Amazon warehouses. Amazon is hoping that Vulcan robots will be able to stow 80 percent of these items at a rate of 300 items per hour, while operating 20 hours per day. It’s a very, very high bar. After a lot of practice, Amazon’s robots are now quite good at the stowing task. Parness tells us that the stow system is operating three times as fast as it was 18 months ago, meaning that it’s actually a little bit faster than an average human. This is exciting, but as Parness explains, expert humans still put the robots to shame. “The fastest humans at this task are like Olympic athletes. They’re far faster than the robots, and they’re able to store items in pods at much higher densities.” High density is important because it means that more stuff can fit into warehouses that are physically closer to more people, which is especially relevant in urban areas where space is at a premium. The best humans can get very creative when it comes to this physical three-dimensional “Tetris-ing,” which the robots are still working on. Where robots do excel is planning ahead, and this is likely why the average robot stower is now able to outpace the average human stower—Tetris-ing is a mental process, too. In the same way that good Tetris players are thinking about where the next piece is going to go, not just the current piece, robots are able to leverage a lot more information than humans can to optimize what gets stowed where and when, says Parness. “When you’re a person doing this task, you’ve got a buffer of 20 or 30 items, and you’re looking for an opportunity to fit those items into different bins, and having to remember which item might go into which space. But the robot knows all of the properties of all of our items at once, and we can also look at all of the bins at the same time along with the bins in the next couple of pods that are coming up. So we can do this optimization over the whole set of information in 100 milliseconds.” Essentially, robots are far better at optimization within the planning side of Tetrising, while humans are (still) far better at the manipulation side, but that gap is closing as robots get more experienced at operating in clutter and contact. Amazon has had Vulcan stowing robots operating for over a year in live warehouses in Germany and Washington state to collect training data, and those robots have successfully stowed hundreds of thousands of items. Stowing is of course only half of what Vulcan is designed to do. Picking offers all kinds of unique challenges too, and you can read our in-depth discussion with Parness on that topic right here.