The Top Hardtech Startups in YC P26
YC's Spring 2026 batch is heavy on AI agents and developer tools, but a handful of companies are building physical things that are hard to ignore. From mobile MRI machines to nuclear reactors that fit on a truck, here are the hardtech standouts from P26.
Adialante: Making MRI Accessible
Adialante (adialante.com) is building compact, mobile whole-body MRI machines designed to make cancer screening something any clinic can offer. Traditional MRI systems cost millions, take months to install, and are loud enough to require ear protection. Adialante has redesigned the technology from the ground up with a patented architecture that cuts hardware by 50%, reduces weight by 80%, uses 60% less power, and runs whisper-quiet.
Co-founders Efrain Torres, PhD and Parker Jenkins met in their engineering dorm and have spent six years inventing new approaches to MRI, securing multiple patents along the way. Rather than selling the machines, Adialante owns and operates them, bringing MRI to clinics in mobile trailers for a flat per-scan fee. No million-dollar purchase. No months of construction. The clinic collects the insurance reimbursement and keeps a margin.
The initial focus is prostate cancer: over a million men per year need an MRI before a prostate biopsy, but almost none of the urology clinics that treat them have a machine. During YC, the team went from a bare magnet to a functional MRI generating preclinical data in eight weeks and surpassed eight figures in letters of intent. From prostate, the same hardware expands to renal, breast, and brain cancer screening.
9 Mothers: AI-Powered Counter-Drone Turrets
9 Mothers (9mothers.com) is building AI-driven counter-drone weapon systems for the U.S. government. The company's AI-powered C-sUAS point defense turret is designed to engage multiple fast-moving drones, with its initial product called EDDA, a compact, energy-efficient, and affordable fully autonomous counter-drone system.
Founded in 2024 by Roman Khomenko, Bogdan Pyzh, and Russell Smith, Khomenko was previously a data scientist at Rainforest QA (YC S12). Their flagship product is a low-power counter-drone system built for deployment on vehicles, at bases, or in a soldier's pack.
General Aviation: Satellite-Based Air Traffic Control
General Aviation is building satellite-based air traffic control systems designed to connect every aircraft, drone, rocket, and ground vehicle to a single global network. Today's ATC infrastructure depends on ground-based radar and communication towers, which leaves large swaths of airspace without coverage and drives up operational costs. General Aviation's approach moves ATC to satellites, with the goal of enabling safer skies, more direct routing, and cutting ATC costs by half.
Apollo Atomics: Compact Nuclear Reactors
Apollo Atomics (apolloatomics.com) is redesigning pressurized water reactors to make them small enough to ship on a flatbed. The company took the pressurized water reactor technology that already powers 80% of the world's nuclear plants and changed one part, the steam generator, to shrink the entire plant by an order of magnitude without losing power output. Their Compact Steam Generator replaces the massive, hand-built component at the heart of a conventional PWR with one that is 20x smaller while delivering the same thermal power.
Co-founder Assil Halimi holds a PhD in Nuclear Engineering from MIT with 15 peer-reviewed publications and 2 patents on reactor design. He previously worked as a reactor operator at Engie, Belgium's nuclear operator, and as an advanced reactor designer at EDF, and has worked with Westinghouse, NuScale, and Rolls-Royce on PWR development. Co-founder Drew previously co-founded Blue Innovations Group, an electric boat startup, and served in the White House.
Apollo recently entered into a research collaboration with MIT's Department of Nuclear Science and Engineering to advance experimental testing of its reactor design. The company submitted its regulatory engagement plan to the NRC earlier this year, with a construction permit application targeted for 2028.
Dispatch: Satellites for Manufacturing in Space
Dispatch (dispatch.space) is building reentry vehicles designed to carry manufactured materials back from orbit. The company builds refurbishable reentry vehicles that host and return payloads for companies making ultra-high-value materials like semiconductors, biotech, and pharma that can only be manufactured in space, solving the bottleneck of getting those products back to Earth.
The team recently returned from the Mojave Desert where they tested their first full-scale reentry heat shield, built to protect the satellite as it returns from space at Mach 20+. They built it in an apartment for 100x less than competitors and held it behind a rocket engine to simulate atmospheric reentry forces. It worked.
CEO Payton Case told Payload the premise is straightforward: if you're going to manufacture in space at scale, you shouldn't have to launch the factory every time. The company aims to fly a 100 kW spacecraft on orbit with 300 kg capacity reentry vehicles that can dock to a station, and is targeting a launch of its uncrewed station in late 2029.
Lumius: 3D Ultrasound for the Body
Lumius (lumius-imaging.com) is building affordable, portable 3D ultrasound systems. Ultrasound is safer and more accessible than CT or MRI, yet the vast majority of clinical imaging is still done in 2D. Clinicians have to mentally reconstruct three-dimensional anatomy from flat images while maneuvering the probe, a skill that takes years to develop. Around half of vascular access attempts fail on the first try, and hospitals spend millions annually on training.
3D ultrasound exists today for cardiac and fetal imaging, but those systems cost roughly 10x more than standard 2D machines. Lumius is building a compact device that delivers real-time 3D imaging at a fraction of the price, starting with vascular access procedures like central lines and expanding into blood clot detection, tumor diagnosis, and biopsy guidance.
The three co-founders, Tri Vu, Luca Menozzi, and Chenhang Li, all hold PhDs from Duke, where they met while researching ultrasound and biomedical engineering.
Synphony: Robots for the Farm
Synphony (synphony.co) is building strawberry-picking robots and farm software. California's strawberry industry alone is worth $3 billion, and labor accounts for around 60% of total costs, yet most farms still run on decades-old software. Synphony provides picking robots alongside analytics and data pipeline tools for growers, while also selling robotics data and benchmarks to foundation model labs as a secondary revenue stream.
Co-founders Lucas Amlicke and Sean Wu bring a mix of robotics and ML experience. Sean previously did ML research at NVIDIA and led AI products used by the IRS and Citibank. Lucas's research spanned robotics, IoT devices, and neuromorphic computing. The team has won over 15 hackathons together. While the initial wedge is strawberries, the company says it has already received inbound interest for robots in semiconductors and autonomous space labs.
Eden Robotics: Industrial Robots for Hire
Eden Robotics (edenrobotics.ai) rents semi-humanoid robots to manufacturing and logistics operators, charging by the hour instead of selling hardware. Traditional industrial automation requires floor plan reworks, onsite engineers, and six to twelve months of deployment. Eden's pitch is robots that work out of the box with no complex integration, lowering the barrier for companies that can't afford to shut down operations for a lengthy install.
The company's stack includes Theta OS, a general-purpose robot operating system, along with a teleoperation layer that keeps a human in the loop when the robot hits an edge case. Rather than discarding failures, the system feeds them back as training data to improve autonomy over time. Co-founder Stamatios Floratos bootstrapped a seven-figure B2B adtech company at 13. Co-founder Joseph Humphreys holds a PhD in robotics with a publication in Nature Machine Intelligence and prior work on rocket engines.