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Helios (spacecraft)
Helios was a pair of German-American solar probes, Helios 1 and Helios 2, launched in 1974 and 1976 into orbits carrying them closer to the Sun than any earlier spacecraft.
Helios Airways Flight 522
Helios Airways Flight 522, the Helios Airways Disaster, was a Cypriot passenger flight that crashed near Grammatiko, Greece, in 2005, killing all 121 on board.
Helios Solar Power Station
The Helios Solar Power Station is a 100 MW parabolic trough solar thermal complex in Ciudad Real, Spain, built by Abengoa and inaugurated in 2012.
Helios-B
Helios-B, also called Helios 2, was a West German–American solar probe launched in January 1976 that held the records for closest approach to the Sun and highest speed until 2018.
Heliosat method
The Heliosat method is a family of algorithms that estimate surface solar irradiance from images taken by geostationary satellites, principally Meteosat, introduced by Cano and colleagues in 1986.
Heliostat
A heliostat is a mirror that tracks the sun on two axes to reflect sunlight onto a fixed target, as in concentrating solar power towers.
Heliotron E
Heliotron E is a helical magnetic-confinement fusion experiment built by Kyoto University, which began operating in 1980 and achieved a record 2 percent plasma beta for helical systems.
Helium ion beam milling
Helium ion beam milling is a nanofabrication technique in which a finely focused helium ion beam sputters atoms from a surface, cutting features as small as 4 to 5 nm.
Helix (AI model)
Helix is a vision-language-action model developed by Figure AI and announced in February 2025 to control its humanoid robots end-to-end from camera pixels and natural-language commands.
Hell Gate Bridge
The Hell Gate Bridge, also called the New York Connecting Railroad Bridge, is a steel through arch railroad bridge over the East River in New York City, opened in 1917.
HellaSwag
HellaSwag is a multiple-choice commonsense sentence-completion benchmark for language models, created at the University of Washington and Allen Institute for AI and published in 2019.
Hellenistic-era warships
Hellenistic-era warships were the oared fighting galleys of the Mediterranean between 323 and 31 BC, when larger galleys replaced the classical trireme as the ship of the line.
Hellisheiði Power Station
Hellisheiði Power Station (Hellisheiðarvirkjun) is the largest geothermal power plant in Iceland, near Reykjavík, generating 303 MW and heating more than half the capital region, and hosts the Carbfix carbon capture project.
Hello, world
"Hello, world", also known as the hello world program, is a small computer program that prints the phrase "Hello, World!", traditionally the first program written when learning a language.
HelloJets
HelloJets is a Romanian ACMI and charter airline based in Bucharest, founded in 2021, that supplies wet-leased aircraft and crews to other airlines and operates charter flights for tour operators.
HelloTalk
HelloTalk is a language-exchange social and messaging app launched in 2012 in which members teach each other their native languages through text, audio, and video chat.
Hells Angels
The Hells Angels Motorcycle Club, also known as HAMC, is an outlaw motorcycle club founded in California around 1950 and one of the largest in the world.
Hells Canyon Dam
Hells Canyon Dam is a 330-foot concrete gravity dam on the Snake River on the Idaho–Oregon border, completed in 1967 and operated by Idaho Power.
HELM (Holistic Evaluation of Language Models)
HELM (Holistic Evaluation of Language Models) is a framework for evaluating large language models, built by Stanford's CRFM and first released in November 2022 to make models comparable head-to-head.
Helmet
A helmet is rigid headgear protecting the head from impact, penetration, or electrical hazards, long used in warfare and now standard safety equipment in industry, motorcycling, cycling, and sport.
Helmet-mounted display
A helmet-mounted display (HMD) is a display on a pilot's helmet showing flight, sensor, and weapon information in the pilot's line of sight, used since the 1960s.
Helmsman
A helmsman, also called a timonier, is the person who steers a boat or ship, operating a tiller, whipstaff, or ship's wheel on the orders of the officer of the watch.
Helmut E. Sobieczky
Helmut E. Sobieczky is an Austrian aerodynamicist who spent his career at DFVLR, later DLR, in Göttingen, known for shock-free transonic design and the PARSEC parametric airfoil method.
Helmuth Glaser
Helmuth Glaser (1906–1985) was a German refrigeration engineer and professor active in Göttingen and Stuttgart, known for the Glaser method, a graphical procedure for assessing interstitial condensation in buildings standardized in DIN 4108-3.
Help point
A help point is a fixed, clearly marked communication unit at a railway station that lets a passenger speak to a human operator, typically by pressing a button.
Helpful and harmless assistant
A helpful and harmless assistant is a language model trained to be useful while avoiding harmful outputs, the core of Anthropic's 2021 HHH alignment framework.
HelpSteer
HelpSteer is a family of open, human-annotated helpfulness datasets released by NVIDIA, spanning three releases from November 2023 to March 2025 under the CC-BY-4.0 license.
Helsing (company)
Helsing, also known as Helsing AI, is a Munich-based defense technology company founded in 2021, best funded in Europe, that builds military AI software and strike drones.
Helsing funding
Helsing funding refers to the venture financing of Helsing, a Munich defense-AI company whose $1.8 billion Series E in July 2026 valued it at $18 billion.
Helsinki Airport
Helsinki Airport, also known as Helsinki-Vantaa Airport, is Finland's largest airport and main international gateway, operated by Finavia and handling about 17 million passengers in 2025.