Faultory investigationshttps://faultory.cc/Interactive, sourced investigations into real engineering failures, scientific discoveries and complex systems.enThe bridge that fed its own motionhttps://faultory.cc/investigations/tacoma-narrows-flutter/https://faultory.cc/investigations/tacoma-narrows-flutter/Engineering & technologyTacoma Narrows, 1940: follow the energy, not just the wind. The first Tacoma Narrows Bridge opened in July 1940. Its unusually slender deck moved visibly in…The number with the missing meaninghttps://faultory.cc/investigations/mars-climate-orbiter-units/https://faultory.cc/investigations/mars-climate-orbiter-units/Engineering & technologyMars Climate Orbiter, 1999: an interface failure across Earth. Mars Climate Orbiter was intended to study Mars and relay communications. It launched in…Two computers, one assumptionhttps://faultory.cc/investigations/ariane-501-common-mode/https://faultory.cc/investigations/ariane-501-common-mode/Engineering & technologyAriane 501, 1996: when backup is not independence. Ariane 5’s first flight ended shortly after launch on June 4, 1996. The launcher carried two inertial…A perfect result from a wrong rulerhttps://faultory.cc/investigations/hubble-wrong-ruler/https://faultory.cc/investigations/hubble-wrong-ruler/Engineering & technologyHubble, 1990: precision without independent accuracy. After Hubble was deployed in April 1990, its images revealed an optical problem: light was not being…The detail that carried two walkwayshttps://faultory.cc/investigations/hyatt-regency-load-path/https://faultory.cc/investigations/hyatt-regency-load-path/Engineering & technologyKansas City, 1981: trace where the weight goes. On July 17, 1981, two suspended walkways collapsed inside the Hyatt Regency hotel in Kansas City. The…The failure that began before launchhttps://faultory.cc/investigations/apollo-13-ground-test/https://faultory.cc/investigations/apollo-13-ground-test/Engineering & technologyApollo 13, 1970: reconstruct a component’s hidden history. Apollo 13 launched on April 11, 1970, aiming for a lunar landing. An oxygen-tank failure during…The grid that lost its warning signshttps://faultory.cc/investigations/blackout-2003-blind-grid/https://faultory.cc/investigations/blackout-2003-blind-grid/Engineering & technologyNortheast blackout, 2003: local faults, regional consequences. On August 14, 2003, a sequence of failures developed into a major blackout across parts of…When previous survival becomes false reassurancehttps://faultory.cc/investigations/columbia-foam-evidence/https://faultory.cc/investigations/columbia-foam-evidence/Engineering & technologyColumbia, 2003: distinguish missing evidence from evidence of safety. During Columbia’s launch on January 16, 2003, insulating foam separated from the…The Missing Pullhttps://faultory.cc/investigations/neptune-the-missing-pull/https://faultory.cc/investigations/neptune-the-missing-pull/Science & DiscoveryAn orbit is wrong. Is the law wrong—or the inventory?. Astronomers can calculate where a planet should appear, then compare that prediction with the sky.…The Noise That Filled the Skyhttps://faultory.cc/investigations/the-noise-that-filled-the-sky/https://faultory.cc/investigations/the-noise-that-filled-the-sky/Science & DiscoveryAn antenna’s unwanted signal becomes a cosmological clue. A low-noise instrument is useful precisely because small unexplained signals become visible. At…The Clock in the Scruffhttps://faultory.cc/investigations/the-clock-in-the-scruff/https://faultory.cc/investigations/the-clock-in-the-scruff/Science & DiscoveryA recurring mark on a chart challenges the interference explanation. Jocelyn Bell Burnell was examining radio-telescope chart records at Cambridge in 1967…The Antarctic Spring Gaphttps://faultory.cc/investigations/the-antarctic-spring-gap/https://faultory.cc/investigations/the-antarctic-spring-gap/Science & DiscoveryA long-running measurement changes when nobody expects it to. A surprising measurement is easier to dismiss when it comes from a difficult place to observe.…The Ocean-Floor Tapehttps://faultory.cc/investigations/the-ocean-floor-tape/https://faultory.cc/investigations/the-ocean-floor-tape/Science & DiscoverySymmetric magnetic stripes test an idea about moving continents. Coastlines can suggest a puzzle, but a visual resemblance alone does not explain a planet.…The Boundary and the Craterhttps://faultory.cc/investigations/the-boundary-and-the-crater/https://faultory.cc/investigations/the-boundary-and-the-crater/Science & DiscoveryA chemical anomaly needs a source, a date, and a mechanism. A thin geological boundary can preserve a signal of an event far larger than the outcrop in…The Clear Zonehttps://faultory.cc/investigations/the-clear-zone/https://faultory.cc/investigations/the-clear-zone/Science & DiscoveryAn antibacterial observation is not yet a usable medicine. In 1928, Alexander Fleming observed that a mold could inhibit nearby bacteria. That observation…The Chirp in Two Placeshttps://faultory.cc/investigations/the-chirp-in-two-places/https://faultory.cc/investigations/the-chirp-in-two-places/Science & DiscoveryA fleeting signal must survive an extraordinary noise investigation. On 14 September 2015, the LIGO detectors at Livingston and Hanford registered a brief…Trading faster, buying lesshttps://faultory.cc/investigations/flash-crash-liquidity/https://faultory.cc/investigations/flash-crash-liquidity/Systems & financeMay 6, 2010: volume is not market depth. On May 6, 2010, US markets fell sharply and then recovered much of the sudden decline. Your task is to distinguish…The eighth serverhttps://faultory.cc/investigations/knight-capital-deployment/https://faultory.cc/investigations/knight-capital-deployment/Engineering & technologyKnight Capital, 2012: a release that was not everywhere. A production release is not a single object. It is a collection of machines, versions, flags and…The city under a lidhttps://faultory.cc/investigations/great-smog-trapped-air/https://faultory.cc/investigations/great-smog-trapped-air/Environment & historyLondon, 1952: emissions meet an atmospheric trap. London's December 1952 smog presents a problem of interacting causes. Smoke sources existed before the…The exception beside the pumphttps://faultory.cc/investigations/broad-street-exposure/https://faultory.cc/investigations/broad-street-exposure/History & discoverySoho, 1854: test the pattern against the people it misses. In the 1854 Soho cholera outbreak, John Snow investigated a possible shared water source. A…A guess that rules things outhttps://faultory.cc/investigations/enigma-constraint-network/https://faultory.cc/investigations/enigma-constraint-network/History & technologyBletchley Park: the machinery behind a testable crib. Enigma was not defeated by one universal password or one person working alone. Polish cryptanalysts…When the destination stops matteringhttps://faultory.cc/investigations/endurance-changing-objective/https://faultory.cc/investigations/endurance-changing-objective/History & explorationEndurance, 1915–1916: revise the mission as the evidence changes. The Endurance expedition set out to cross Antarctica, but a trapped ship turned a…The clock that is right in the wrong placehttps://faultory.cc/investigations/gps-relativistic-clocks/https://faultory.cc/investigations/gps-relativistic-clocks/Science & technologyGPS: a design investigation, not a historical outage. This investigation is a design thought experiment grounded in real GPS physics, not a claim that an…A photograph without filmhttps://faultory.cc/investigations/kodak-digital-prototype/https://faultory.cc/investigations/kodak-digital-prototype/History & technologyKodak, 1975: distinguish a working principle from a finished product. In 1975, Steven Sasson built a self-contained digital camera prototype at Kodak. It…