You asked about Aviation and Space
123 people built something like it. 13 are gone.
That is 11% of the ones whose fate we could settle, against 23% across the whole register. 6 were acquired.
| Launched | What it was | Today |
|---|---|---|
| 2016-01-01 | Building humanity’s multiplanetary future. · relativityspace.com | still up |
| 2016-01-01 | YCAstranis Advanced satellites for high orbits. · astranis.com | still up |
| 2021-01-01 | Seamless mobility to, through, and from space. It starts with 100%… · stokespace.com | still up |
| 2016-01-01 | YCBoom Economically and environmentally sustainable supersonic travel · boomsupersonic.com | still up |
| 2018-06-01 | YCMomentus The space infrastructure services company · momentus.space | acquired |
| 2022-01-01 | First electric business aircraft designed for hydrogen propulsion · beyond-aero.com | still up |
| 2017-06-01 | YCPyka Autonomous electric airplanes · flypyka.com | still up |
| 2021-01-01 | The lightest electric aircraft motors in the world. · h3x.tech | still up |
| 2021-01-01 | YCAlbedo Full-stack VLEO satellite missions · albedo.com | still up |
| 2024-01-01 | Supersonics for the new Jet Age · astromecha.co | still up |
| 2019-01-01 | Heart makes electric airplanes with an all-electric range of 250 miles · heartaerospace.com | still up |
| 2022-01-01 | Bluetooth to Space · hubble.com | still up |
| 2021-01-01 | YCREGENT All-electric seagliders for fast, affordable regional transportation · regentcraft.com | still up |
| 2019-01-01 | The Rocket Network: Sustainable & On-Demand Delivery Anywhere in Space · spaceryde.com | gone |
| 2022-06-01 | We're building satellites to create a real-time 3D map of the world. · arraylabs.io | still up |
| 2021-06-01 | Turning space into a transportation layer for Earth · inversionspace.com | still up |
| 2022-01-01 | YCWyvern High-res hyperspectral pictures of Earth from space · wyvern.space | still up |
| 2020-01-01 | Long range, battery electric vertical take-off and landing aircraft. · talyn.com | acquired |
| 2021-06-01 | Moving Things Around in Space, Imaging Space Objects When We're Not · turionspace.com | still up |
| 2019-06-01 | Last-mile delivery for satellites. · epic-aerospace.com | still up |
| 2020-01-01 | Developing supersonic UAVs as a pathway to quiet supersonic flight · exosonic.com | gone |
| 2020-01-01 | YCFarcast We build advanced satcom user terminals · farcast.com | still up |
| 2024-06-01 | Data centers in space · starcloud.com | still up |
| 2025-01-01 | Reusable Satellites · reditus.space | still up |
| 2021-06-01 | Vertical takeoff and landing aircraft for major airlines · odysaviation.com | still up |
| 2021-01-01 | We make satellites to image everywhere on Earth, every 15 minutes · albaorbital.com | still up |
| 2025-01-01 | High Thrust Space Vehicles for Satellite Defense · orbitalops.tech | still up |
| 2022-06-01 | Airplanes anyone can fly · airhartaero.com | still up |
| 2019-01-01 | Flying motorcycles · jetpackaviation.com | still up |
| 2025-09-01 | The Modular Interceptor Platform · wardstone.us | still up |
| 2026-01-01 | Space solar arrays that grow to the size of a football field in orbit · beyondreachlabs.com | still up |
| 2021-06-01 | Orbital logistics: Unleashing space industry, from Earth to asteroids · transastra.com | still up |
| 2024-09-01 | YCGander Automation System for Global Aviation · usegander.com | acquired |
| 2024-01-01 | Agent-Driven Engineering · navier.ai | still up |
| 2024-09-01 | YCApolink 24/7 satellite connectivity in low Earth orbit · apolink.space | still up |
| 2023-01-01 | YCRadical Building persistent, high-performance infrastructure in the sky · radicalaero.com | still up |
| 2017-06-01 | Tesseract builds better thrusters for modern satellites · tesseract.space | still up |
| 2024-01-01 | YCBasalt Constellations as a Service · basalt.space | still up |
| 2022-06-01 | YCVelontra Hypersonic space plane that can take-off from any location and weather · velontra.com | still up |
| 2024-01-01 | YCElodin Unified flight software and hardware for the mission of tomorrow · elodin.systems | still up |
| 2026-01-01 | Moon Hotel -> The Intergalactic Construction Company of Earth · gru.space | still up |
| 2025-01-01 | Building lunar landers · instinct-space.com | still up |
| 2022-06-01 | We make the world's most efficient aircraft · seaflight.tech | still up |
| 2017-01-01 | Boeing for electric planes · weflywright.com | still up |
| 2023-01-01 | Emission free hydrogen electric aircraft · stralis.aero | still up |
| 2021-06-01 | We visually monitor space objects for governments and defense · heo-robotics.com | still up |
| 2026-09-01 | AI spacecraft operators that lives onboard the vehicle · orcaaerospace.com | still up |
| 2026-01-01 | Robotics for Space R&D · generalastro.com | still up |
| 2017-06-01 | Passerine Aircraft is building the next generation of dronesWe are… · passerineaircraft.com | gone |
| 2026-01-01 | Foundation models for 24/7 Earth Observation · axionorbital.space | still up |
| 2026-06-01 | We make silicon on the Moon, to power everything in space. · ethos-space.com | still up |
| 2024-06-01 | Building low-cost cruise missiles · aresindustries.com | still up |
| 2015-01-01 | Launch small satellites · bagaveev.com | gone |
| 2024-09-01 | AI that gets aircraft flying faster · tryforerunner.com | still up |
| 2021-01-01 | The highest-accuracy global weather data from low-cost flat satellites · careweather.com | still up |
| 2025-01-01 | AI for air traffic control · enhancedradar.com | still up |
| 2016-06-01 | Prime Lightworks Inc. manufactures electric propulsion systems for… · primelightworks.com | still up |
| 2023-06-01 | Building and Protecting an Exciting Future · singularityus.com | still up |
| 2024-09-01 | YCConsus The fastest and cheapest way to use AI with ITAR or CUI data. · consus.io | still up |
| 2026-06-01 | YCExosat Building a neutral, sovereign alternative to Starlink · exosat.com | still up |
How this compares
The register re-probes every domain it holds. Some that answered last month stop answering. We send that list — what went quiet, and what it was — once a month. Nothing else.
How this was made. Show HN entries are every post from 2021 to 2023 with at least five points that linked to its own domain; code hosts and free hosting are excluded, because a repository outlives the effort behind it. Product Hunt entries needed 100 votes — a far higher bar, so they are the promoted top slice rather than a like-for-like sample. Both are judged by asking the domain whether it still answers: gone means it no longer resolves, refuses the connection, serves a parking page, or says plainly that it shut down. An HTTP error is not counted as gone — a server answering 404 is one somebody still pays for, and an audit of 25 gone-calls found two such sites alive with only a moved homepage. Y Combinator entries use the status YC publishes itself, which is why only those can say acquired. Squatted domains — a lapsed name now serving somebody else's site — are not detected, so these figures run slightly low.