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S2

S2 may refer to topics in various fields, including science and technology, transportation, military and defense, organizations, products, and other uses. For detailed information, see the relevant sections below.

Science and technology

Mathematics

In mathematics, the notation S^2 commonly denotes the 2-sphere, defined as the set of points in three-dimensional Euclidean space \mathbb{R}^3 at a fixed distance of 1 from the origin, or equivalently, the surface of the unit ball. Formally, S^2 = \{ (x, y, z) \in \mathbb{R}^3 \mid x^2 + y^2 + z^2 = 1 \}. This geometric object serves as a foundational example in differential geometry and topology.^[1] Topologically, S^2 is a compact, connected 2-manifold without boundary, meaning every point has a neighborhood homeomorphic to an open disk in \mathbb{R}^2, and the space is finite and path-connected. It is orientable and simply connected, with fundamental group \pi_1(S^2) = 0, distinguishing it from higher-genus surfaces. The standard parametrization of S^2 uses spherical coordinates (\theta, \phi), where \theta \in [0, \pi] is the colatitude and \phi \in [0, 2\pi) is the longitude:

\begin{align*} x &= \sin \theta \cos \phi, \\ y &= \sin \theta \sin \phi, \\ z &= \cos \theta. \end{align*}

This parametrization covers S^2 except for coordinate singularities at the poles (\theta = 0, \pi), but charts can resolve these for manifold structure.^[2]^[3] The study of S^2 as a manifold emerged in the late 19th century through the foundational work of Henri Poincaré, who introduced concepts in algebraic topology to classify surfaces and higher-dimensional analogs. In his 1895 paper "Analysis Situs," Poincaré developed homology groups to analyze the connectivity and holes in manifolds like S^2, laying the groundwork for modern topology by treating the sphere as a prototype for compact orientable surfaces of genus zero.^[4]

Biology and medicine

In cardiology, the second heart sound, denoted as S2, is generated by the closure of the aortic (A2) and pulmonic (P2) valves at the end of systole, marking the onset of diastole.^[5] This sound is typically heard as a single or split component during auscultation, with A2 being louder and more prominent due to higher left ventricular pressures compared to the right side.^[6] Clinically, variations in S2 timing and intensity provide diagnostic insights into cardiovascular conditions; for instance, delayed A2 closure can indicate aortic stenosis or left bundle branch block, while accentuated P2 suggests pulmonary hypertension.^[7]^[8] A key abnormality is the splitting of S2, where the interval between A2 and P2 components varies with respiration. Physiologic splitting widens during inspiration due to delayed P2 from increased venous return to the right heart, narrowing during expiration.^[5] Pathologic patterns include fixed splitting, often seen in atrial septal defects where respiratory variation is absent, and paradoxical splitting, which reverses the normal pattern—widening on expiration and fusing on inspiration—typically due to delayed left ventricular ejection in conditions like severe aortic stenosis or left bundle branch block.^[9]^[8] Auscultation of these S2 variants aids in assessing valve function, ventricular synchrony, and hemodynamics, guiding diagnoses of hypertension, congenital defects, and conduction abnormalities.^[10] The S2 subunit of the SARS-CoV-2 spike protein plays a critical role in viral entry by mediating membrane fusion between the viral envelope and host cell membrane following receptor binding by the S1 subunit.^[11] Cleavage at the S1/S2 boundary by host proteases exposes the fusion peptide in S2, enabling conformational changes that drive fusion.^[12] Structurally, S2 features two heptad repeat regions, HR1 and HR2, which form a six-helix bundle essential for stabilizing the post-fusion conformation and facilitating efficient viral infection.^[13] These regions are highly conserved across betacoronaviruses, making S2 a stable target less prone to variant escape compared to S1.^[14] In vaccine development, the conserved nature of S2 has driven efforts to elicit broad immunity against multiple coronaviruses. Targeting HR1 and HR2 with subunit vaccines or peptides induces neutralizing antibodies that inhibit fusion and cross-protect against SARS-CoV-1, seasonal coronaviruses, and emerging SARS-CoV-2 variants.^[15] As of 2025, studies demonstrate that S2-based immunogens, such as glycan-free HR2 peptides conjugated to virus-like particles, generate robust T-cell and antibody responses for pan-coronavirus protection in preclinical models.^[16]^[17] These approaches complement S1-focused vaccines by addressing limitations in variant evasion and long-term immunity.^[18] In developmental biology, Drosophila S2 cells, derived from Schneider 2 embryonic cell lines, are widely used to study cell proliferation and division dynamics during metamorphosis and tissue growth. These cells undergo synchronized divisions regulated by cyclin-dependent kinases and checkpoints, mimicking proliferative stages in embryogenesis.^[19] Disruptions in these processes can lead to developmental arrests, highlighting their role in coordinating cell cycle with hormonal cues like ecdysone during pupal transitions.^[20]

Computing

The Google S2 Geometry Library is an open-source C++ library developed by Google for performing computational geometry operations on the sphere, particularly suited for geospatial indexing and analysis at global scales.^[21] It represents the Earth's surface using a hierarchical tiling system composed of S2 cells, which are spherical quadrilaterals organized in a quadtree-like structure across 30 levels of subdivision, enabling precise and efficient handling of spherical data without distortions from planar projections.^[22] Unlike conventional geographic information systems that rely on 2D flat maps, the library operates natively in 3D spherical coordinates, supporting applications in large-scale databases for tasks such as region covering and intersection computations.^[23] A core component is the S2CellId, a unique 64-bit integer that encodes the position and level of any S2 cell, facilitating fast lookups and indexing in databases.^[22] The library includes algorithms for proximity searches, such as finding all cells within a specified radius of a point, and covering algorithms that approximate regions with minimal overlapping cells, which are essential for optimizing spatial queries in systems handling billions of geospatial points.^[21] It has been integrated into Google's internal geographic infrastructure and is available for use in external projects, including R bindings via the s2 package for spatial operations akin to those in BigQuery's geography functions.^[24] Bindings exist for languages like Java and Python, broadening its adoption in geospatial data processing for efficient proximity-based routing and analysis.^[25] In the context of scholarly data processing, the S2 platform from the Allen Institute for AI employs S2AND, a machine learning-based system for author name disambiguation (AND) in bibliographic records.^[26] S2AND introduces a unified benchmark dataset that harmonizes eight diverse AND datasets into a standardized format, incorporating rich features extracted from the Semantic Scholar corpus, such as co-authorship patterns, publication venues, and citation networks, to address ambiguities in author identities across millions of papers.^[27] The system's open-source reference model, implemented using supervised learning techniques like gradient-boosted trees, evaluates performance on key metrics including precision (up to 98.5% on held-out test sets), recall (around 95%), and F1-score (averaging 96.7%), outperforming prior methods on tasks like clustering ambiguous name clusters.^[28] As of its 2021 release, S2AND has become a standard for benchmarking AND algorithms, enabling improved accuracy in linking authors to their works within large-scale academic search engines.^[29] In historical military computing, the S2 Automated Agent (S2A2) serves as a simulation-based training tool designed to emulate the intelligence functions of an S2 officer in U.S. Army operations.^[30] Developed in the late 1990s, S2A2 integrates with existing Army battle simulation systems to process war plans, generate automated intelligence reports, and support rapid situational analysis, using rule-based and probabilistic models to simulate enemy courses of action and terrain assessments.^[31] Its technical specifications include compatibility with modular simulation architectures, low-latency processing for real-time decision support (under 5 minutes for estimate generation), and interfaces for staff-assisted planning, making it a foundational example of AI-assisted computing in military intelligence workflows.^[30]

Astronomy and physics

In astronomy, S2, also denoted as S0-2, is an early-type B star (spectral type B0–2.5 V) in the Galactic Center, orbiting the supermassive black hole Sagittarius A* at a distance of approximately 120 astronomical units at its closest approach.^[32] Observations of S2 began in 1995 using adaptive optics on ground-based telescopes like the Keck Observatory, revealing its highly elliptical orbit with an eccentricity of about 0.88 and a semi-major axis of roughly 970 AU.^[33] The orbital period is precisely measured at 16.0518 ± 0.014 years, completing full orbits observed in 2002 and 2018 pericenter passages, providing key evidence for the 4.3 million solar mass black hole at the Milky Way's core.^[34] Relativistic effects in S2's orbit have been confirmed through high-precision astrometry and spectroscopy. During the 2018 pericenter, the GRAVITY instrument on the Very Large Telescope detected the gravitational redshift, with the star's velocity blueshifted by up to 200 km/s and redshifted post-pericenter, matching general relativity predictions to within 4% after accounting for special relativistic Doppler effects.^[33] Additionally, the Schwarzschild precession of the orbit— approximately 12 arcminutes advance per revolution due to the black hole's spacetime curvature— was directly measured using GRAVITY data spanning 2016–2019, confirming the prograde precession at the level expected from general relativity without needing alternative gravity theories.^[34] These observations, combined with Event Horizon Telescope imaging of Sagittarius A* in 2022, underscore S2's role as a probe of strong-field gravity near the event horizon. A 2025 analysis of S2's orbit suggests indications of collisional processes shaping the inner Galactic Center, including potential tidally disrupted binaries.^[35] In quantum mechanics, the S2 state denotes the n=2, l=0 (s-wave) energy level in atomic spectra, particularly the 2S_{1/2} hyperfine state in hydrogen, where the electron's principal quantum number is 2 and total angular momentum j=1/2. This metastable state, with a lifetime of about 0.12 seconds due to two-photon decay to the 1S ground state, is crucial for precision spectroscopy.^[36] Measurements of the 1S-2S transition frequency, around 2.466 × 10^{15} Hz, have achieved uncertainties below 10^{-15}, testing quantum electrodynamics through the Lamb shift (about 1057 MHz splitting from 2P_{1/2}) and hyperfine structure, with antihydrogen spectroscopy confirming CPT symmetry to high precision.^[37]

Transportation

Automobiles

The AS S1 and AS S2 were passenger cars, including taxi landaulets and limousines, produced in Poland by Towarzystwo Budowy Samochodów AS, a Warsaw-based manufacturer established in 1924 and designed by Aleksander Liberman. The S2 model featured a 1,203 cc CIME inline-four engine producing 24 kW (approximately 32 horsepower), four-wheel brakes, full electrical equipment, and a top speed of 85 km/h. Production totaled approximately 150 units before the company ceased operations in 1930 due to the Great Depression; no known surviving examples exist. The Audi S2, manufactured from 1990 to 1995, was a high-performance variant of the Audi 80 (B3/B4 platform), available as a coupe, cabriolet, and avant wagon.^[38] It was powered by a turbocharged 2.2-liter inline-five engine (codes 3B or ABY) delivering 220 horsepower in early models and up to 230 horsepower in later versions, paired with Audi's quattro all-wheel-drive system and a five-speed manual transmission.^[39] Key features included a 0-100 km/h acceleration time of approximately 6.1 seconds, a top speed of 248 km/h, and advanced suspension for sporty handling, making it a precursor to later Audi S models.^[40] A total of around 9,488 units were produced, emphasizing its role as a compact executive performance car.^[38] The Lotus Elise Series 2 (S2), produced from 2001 to 2011, was a lightweight roadster succeeding the original Series 1, renowned for its extruded aluminum chassis and minimalist design weighing under 800 kg.^[41] It utilized a Toyota-sourced 1.8-liter VVTL-i inline-four engine, with base models offering 122 horsepower and higher variants like the 111R reaching 189 horsepower, while supercharged SC editions peaked at 220 horsepower for enhanced track performance.^[42] Notable features included a mid-engine layout for balanced handling, a five- or six-speed manual gearbox, and open-top configuration, achieving 0-100 km/h in as little as 4.0 seconds in sportier trims.^[41] Over 25,000 Elises were built across series, with the S2 emphasizing purist driving dynamics and affordability in the sports car segment.^[43] The Porsche 944 S2, built from 1989 to 1991, served as the final naturally aspirated evolution of the 944 grand tourer lineup, featuring a 3.0-liter DOHC inline-four engine (derived from the 2.5-liter base) producing 208 horsepower and 300 Nm of torque.^[44] Equipped with a five-speed manual transmission, independent suspension, and iconic pop-up headlights, it prioritized precise handling and long-distance comfort, with a 0-100 km/h time of 6.9 seconds and a top speed of 240 km/h.^[45] Offered primarily as a coupe with optional cabriolet, the S2 bridged the gap to the 968 successor, with production totaling about 9,000 units and strong resale value due to its balanced performance.^[46]

Roads and bus routes

The S2 expressway in Poland serves as the southern bypass of Warsaw, forming a key segment of the city's ring road and connecting the A2 motorway from the west to the east. Spanning approximately 33 kilometers, it includes Poland's longest road tunnel at 2.3 kilometers under the Ursynów district, which opened in late 2021 to alleviate urban congestion and improve east-west connectivity. This route is managed by the General Directorate for National Roads and Motorways (GDDKiA) and handles significant daily traffic, with ongoing expansions to enhance capacity.^[47] In the United States, County Route S2 in California stretches over 75 miles through the Imperial and San Diego counties, linking the desert town of Ocotillo to Warner Springs via the Anza-Borrego Desert State Park. Established in 1970, this two-lane highway follows portions of the historic Great Overland Stage Route from 1849 and was once designated a "survival route" during the Cold War era for potential evacuation from San Diego in the 1950s and 1960s. Maintained by county authorities, it features rugged terrain with elevations up to 4,235 feet at Sweeney Pass and supports tourism to desert landscapes.^[48] Georgia's S2 highway, also known as the Senaki-Poti-Sarpi route, runs about 119 kilometers along the Black Sea coast from Senaki through Poti and Batumi to the Turkish border at Sarpi.) Classified as a road of international importance, it forms part of the European E60, E70, and E97 corridors and the Asian Highway Network AH5, primarily as a two-lane road passing through coastal villages and cities. Upgrades under the East-West Highway project have improved sections for better freight and tourist access since the early 2010s.^[49] In Sweden, Riksväg 2 (National Road 2), often referred to as Rikstvåan, extends 570 kilometers parallel to the E6 motorway from Trelleborg in the south to the Norwegian border at Svinesund. This route connects major southern cities like Malmö, Helsingborg, and Gothenburg, serving as an alternative to the primary E6 with a mix of two- and four-lane sections managed by Trafikverket. It supports regional traffic and has seen safety enhancements, including barrier installations, in recent years. Public bus routes designated S2 operate in several urban areas, providing efficient local and suburban connectivity. In London, United Kingdom, Transport for London (TfL) route S2 runs 14 kilometers from Epsom Clock Tower to St Helier Station, serving Sutton and surrounding residential areas with services every 15-30 minutes daily. Introduced in the early 2000s and fully converted to electric vehicles by 2024, it uses zero-emission double-decker buses to reduce environmental impact along its path through suburban neighborhoods.^[50]^[51] In Berlin, Germany, the S-Bahn S2 line functions as a high-frequency public transit route on the suburban rail network, circling through central districts including Potsdamer Platz with trains departing every 10 minutes during peak hours. Operated by S-Bahn Berlin GmbH over 46 kilometers with 28 stations, it connects Blankenfelde in the south to Bernau in the north via the North-South tunnel, integrating seamlessly with broader rail systems for commuter travel.^[52]^[53] Historically, several S2-designated routes have been discontinued or reclassified due to shifting priorities in infrastructure planning. In California, an early proposal for an S2 alignment as part of interstate evacuation networks was abandoned in the 1960s after initial Cold War-era considerations, with the current county route evolving from older state paths like the Imperial Highway. These changes reflect broader U.S. trends in prioritizing interstate systems over secondary desert routes.^[54]

Aviation

The Grumman S-2 Tracker was the first purpose-built carrier-based anti-submarine warfare (ASW) aircraft for the United States Navy, entering service in the mid-1950s and remaining operational through the 1980s.^[55] Originally designated the S2F-1 under the pre-1962 Tri-Service aircraft reporting system, it featured a twin-engine radial piston configuration powered by two Wright R-1820 Cyclone engines, each producing 1,525 horsepower, enabling a maximum speed of approximately 265 mph and an endurance of up to 9 hours for extended patrols.^[56] The aircraft was equipped with advanced ASW systems, including an AN/APS-20 search radar housed in a prominent nose radome, sonobuoy dispensers, and provisions for depth charges, torpedoes, or nuclear weapons, allowing it to detect and engage submerged submarines effectively during the Cold War era. Over 1,200 units were produced between 1954 and 1968, serving primarily on escort carriers and later adapted for utility roles such as cargo transport (COD) and electronic warfare (ES-2F variant).^[57] Many Trackers were exported to allied navies, including Canada and Australia, where they continued ASW duties into the 1990s before retirement due to the rise of turbine-powered successors like the S-3 Viking.^[58] In British aviation nomenclature, the Short S.2, also known as the Short Biplane No. 2 or Improved Type No. 2, represented an early experimental milestone in powered flight. Built by Short Brothers in 1909, this pusher biplane was a refined version of the Wright Flyer design, incorporating ailerons for lateral control instead of wing-warping, a 50-horsepower J.A.P. engine, and a wheeled undercarriage for improved takeoff.^[59] On October 20, 1909, pilot J.T.C. Moore-Brabazon used the Short S.2 to complete the first circular mile flight by a British-built powered aircraft at Wormwood Scrubs, London, earning the £1,000 Daily Mail prize and marking a pivotal moment in the UK's aviation development.^[60] Only a single example was constructed, as Short Brothers shifted focus to licensed Wright and Farman types, but the S.2's success helped establish the firm as a leader in British aeronautics, influencing subsequent designs during World War I.^[59] Space-related designations incorporating S2 have appeared in NASA's sounding rocket and launch vehicle programs, particularly for suborbital and orbital missions from the 1960s onward. The S-2 stage, derived from the Minuteman II intercontinental ballistic missile's second stage, formed a key component of the Aries sounding rocket family, a four-stage solid-propellant vehicle used for high-altitude atmospheric and astrophysics research.^[61] Introduced in the 1980s as part of the NASA Sounding Rockets Program (SRP), which traces its origins to 1959, the Aries with S-2 enabled payloads up to 739 kg to reach altitudes exceeding 1,000 km, supporting experiments on plasma physics, solar-terrestrial interactions, and middle atmosphere dynamics from sites like Wallops Flight Facility and White Sands Missile Range.^[61] Its propellant mass was less than 25% of the original Minuteman stage, ensuring reliable performance with a vehicle success rate over 95% across more than 2,700 SRP launches by the 1990s. In orbital contexts, the S-II stage of the Saturn V rocket, operational from 1967 to 1973, propelled early satellite missions such as Nimbus weather satellites and Orbiting Solar Observatories, burning liquid hydrogen and oxygen via five J-2 engines to achieve velocities over 15,000 mph for precise insertions.^[62] These S2 designations underscored the evolution of aviation into space access, bridging military missile technology with civilian scientific exploration.^[63]

Rail transport

The Pennsylvania Railroad's S2 class was an experimental steam turbine-electric locomotive introduced in 1944 as a one-off prototype to explore high-speed passenger haulage capabilities.^[64] Powered by a 6,900 horsepower Westinghouse direct-drive steam turbine engine with a 6-8-6 wheel arrangement, it featured a fixed 18.5:1 gear ratio optimized for sustained high speeds, achieving up to 110 mph during tests with passenger consists.^[65] The locomotive was employed primarily for experimental runs on the PRR's main lines, including dynamometer car trials pulling 17-car trains over 30 miles, but its design limitations—such as poor low-speed efficiency and high coal consumption below 45 mph—prevented broader adoption before diesel-electric units dominated post-World War II.^[64] In the realm of diesel switchers, the ALCO S-2 represented a staple of yard operations from the 1940s through the 1960s, with over 1,500 units produced by the American Locomotive Company and its Canadian licensee, Montreal Locomotive Works. Equipped with a 1,000 horsepower McIntosh & Seymour 539 six-cylinder engine in a B-B configuration, the S-2 was designed for heavy switching duties in rail yards, offering reliable low-speed torque for shunting freight cars and light transfer service across North American railroads. Its end-cab layout and compact frame made it versatile for industrial and short-haul applications, though many were phased out by the 1970s in favor of more modern designs; surviving examples continue in tourist and preservation service.^[66] Among passenger services, the Berlin S-Bahn's S2 line operates as a key circumferential route on the 37.5 km Ringbahn loop, connecting southern suburbs like Blankenfelde to northern areas such as Bernau via the city's outer ring.^[52] Introduced as part of the electrified suburban network that began operations in 1924 with the first electric multiple units on initial sections, the S2 utilizes ET 485-class trains for frequent urban and commuter travel, with the full Ringbahn electrification completed by 1929 to support rapid transit demands. In 2025, Deutsche Bahn initiated major upgrades on the Anhalter Bahn segment of the S2 route, including 130 km of track renewal, 33 new switches, and full replacement of 100 km of rails to enhance reliability and capacity amid growing ridership, as of September 2025 with works scheduled for completion by December 2025.^[67] The Swiss S-Bahn S2 provides regional connectivity in the Zürich area, running from Zürich Flughafen through Zürich Hauptbahnhof to Pfäffikon SZ and Ziegelbrücke, with extensions serving the densely populated corridor toward Winterthur via interconnecting lines.^[68] Operated by SBB with modern RABe 511 low-floor electric multiple units, the service maintains a frequency of every 30 minutes during peak hours, facilitating efficient airport-to-city and interurban links for over 100,000 daily passengers in the Zürich transport association (ZVV) network. This hourly off-peak rhythm supports broader integration with the Zurich–Winterthur railway, one of Switzerland's busiest lines opened in 1855, emphasizing punctual and accessible commuter rail.^[69]

Military and defense

Staff and operations

In military organizations, the S2 designation refers to the intelligence staff section, responsible for providing critical intelligence support to commanders through collection, analysis, and dissemination processes. This role originated in the U.S. Army's adoption of the general staff system during World War I, influenced by French and Prussian models, where the G2 (and battalion-level S2) was established to handle intelligence functions amid the demands of modern warfare.^[70] Pioneered by figures like Ralph Van Deman and Dennis Nolan, who founded the Military Intelligence Section in 1917, the S2 focused on enemy assessments and counterintelligence to support operational decisions.^[70] Post-World War II, the role was formalized in U.S. Army doctrine, such as Field Manual 101-5 (Staff Organization and Operations, 1940s editions onward), integrating S2 into permanent battalion structures for peacetime training and mobilization, emphasizing standardized procedures for intelligence preparation and security. In the U.S. Army, the S-2 Intelligence Officer at the battalion level serves as the principal advisor to the commander on all intelligence matters, leading a section that synchronizes multi-discipline collection using organic assets like human intelligence (HUMINT) and signals intelligence (SIGINT), as well as external support from units such as U.S. Army Cyber Command. This includes developing information collection plans based on priority intelligence requirements (PIRs), tasking reconnaissance assets, and monitoring results to address specific information requirements (SIRs) across operational phases. The S-2 conducts all-source analysis to produce threat assessments, evaluating enemy capabilities, intentions, and vulnerabilities, often through the Intelligence Preparation of the Operational Environment (IPOE) process, which involves defining the operational environment, describing its effects (e.g., terrain and weather), assessing threats, and determining adversary courses of action (COAs). Key products include situation templates, event matrices, and running estimates that support the Military Decision-Making Process (MDMP) and targeting, with dissemination occurring via timely reports like the common intelligence picture (CIP) to ensure shared situational awareness. The S-2 also oversees security and counterintelligence operations, managing personnel security clearances in compliance with Department of Defense Manual 5240.01, supervising command security programs, and countering threats such as espionage, sabotage, and cyberattacks through collaboration with operations security (OPSEC) officers. This includes identifying foreign intelligence threats, providing early warnings, and integrating counterintelligence into force protection, as outlined in FM 2-0 (updated 2023), which emphasizes the S-2's role in multidomain operations to mitigate risks from peer adversaries. In battalion settings, the S-2 coordinates with the S-3 (operations) to align intelligence with maneuver plans, ensuring products like high-value target (HVT) lists and battle damage assessments inform fires and risk management.^[71] In joint and multinational operations, particularly under NATO, the S2 (or equivalent G2 at higher echelons) provides security and intelligence support, leading collaborative efforts like Intelligence Preparation of the Battlefield (IPB) to analyze operational environments and threat COAs in alliance contexts. NATO staff structures, as described in allied joint publications, position the S2/G2 within planning teams (e.g., alongside J2 and S3) to synchronize intelligence for combined joint task forces, focusing on shared assessments of adversary intentions and multinational force protection during operations. This role ensures interoperability in NATO missions, with the S2 handling tactical intelligence processing and dissemination to support commanders in diverse environments, such as stability operations or crisis response.^[72]

Equipment and vehicles

The Pantsir-S2 is a Russian self-propelled short-range air defense system designed to protect ground forces, military installations, and infrastructure from aircraft, helicopters, precision-guided munitions, and unmanned aerial vehicles. Developed by KBP Instrument Design Bureau as an upgrade to the Pantsir-S1, it features a wheeled 8x8 chassis based on the KamAZ-6560 truck, providing enhanced mobility with a top speed of 90 km/h and an operational range of up to 500 km. The system integrates two 30mm 2A38M autocannons with a rate of fire of 5,000 rounds per minute each and up to 12 surface-to-air missiles (primarily 57E6 or improved variants) housed in twin launchers, capable of engaging targets at altitudes from 5 meters to 15 km and ranges up to 30 km. Its multi-band radar suite, including the upgraded SOTS thermal imaging system, allows simultaneous tracking of up to 40 targets and engagement of 4, with improved electronic countermeasures for low-altitude and small RCS threats. Exported to countries like the United Arab Emirates, Algeria, and Serbia, the Pantsir-S2 has seen combat use in conflicts such as the Syrian Civil War and the Russia-Ukraine war, where it has demonstrated effectiveness against drones but also vulnerabilities to saturation attacks.^[73] The Grumman S-2 Tracker, redesignated from S2F in 1962, was a carrier-based anti-submarine warfare aircraft developed for the U.S. Navy, entering service in 1954 as the first purpose-built ASW platform with integrated detection, classification, and attack capabilities. Powered by two Wright R-1820 Cyclone radial engines producing 1,525 horsepower each, it had a maximum speed of 435 km/h, a range of 1,960 km, and could carry up to 4,000 pounds of ordnance including sonobuoys, depth charges, torpedoes, and nuclear ASW weapons. Its surveillance adaptations included a distinctive "stoof" radome housing an APS-20 search radar for surface and subsurface detection up to 50 km, magnetic anomaly detectors (MAD) for submarine localization, and sonobuoy processing systems for acoustic surveillance, enabling real-time threat assessment in maritime patrol roles. Over 1,200 units were produced, with variants like the S-2E incorporating improved electronics for electronic intelligence (ELINT) gathering. Post-U.S. retirement in 1976, upgraded Trackers served in surveillance capacities with navies such as Argentina's, where S-2T Turbo Tracker variants returned to service in July 2025 after a period of grounding since 2023 due to spare parts issues (with aircraft 2-AS-23 reactivated on July 11), but as of late 2025, the Argentine Navy is evaluating their retirement for coastal defense and search-and-rescue monitoring, equipped with modern avionics for enhanced radar and infrared surveillance.^[74]^[75]

Organizations

Entertainment and media

In the music industry, S2 Records operated as a subsidiary of Sony Music Entertainment during the late 1990s and early 2000s, focusing on alternative rock, pop, and funk acts based in the United Kingdom. Originally named Sony Soho Square after its London location, the label released notable albums including Jamiroquai's Synkronized in 1999, which featured the hit single "Canned Heat" and debuted at number one on the UK Albums Chart. Other artists on the roster included Des'ree, whose soulful tracks like "Life" gained international acclaim; Reef, known for their Britpop sound on albums such as Glow (1997); and Jimmy Ray, who achieved moderate success with his 1997 debut See What You Want to See blending pop and funk elements. The label was shut down on September 30, 2002, as part of Sony Music Entertainment UK's consolidation of its divisions, with its catalog later integrated into Sony's broader holdings following the 2004 merger of Sony Music and BMG.^[76] Additionally, WWF SmackDown! 2: Know Your Role (2000) is a professional wrestling video game for the PlayStation console, often abbreviated as SmackDown 2. Developed by Yuke's and published by THQ, it was released on November 20, 2000, in North America, expanding on the original WWF SmackDown! with an expanded roster of over 35 wrestlers, including stars like The Rock, Triple H, and Chyna. The game introduced a deeper story mode called "Season Mode," enhanced grappling mechanics, and new match types like Ladder Matches, earning critical acclaim for its fast-paced gameplay and authentic WWF atmosphere, with a Metacritic score of 90/100. It sold over one million copies in its first year, solidifying the series' popularity during the WWF's Attitude Era.

Business and industry

S2 Yachts, Inc., was an American sailboat and powerboat manufacturer founded in 1974 by Leon Slikkers in Holland, Michigan, initially focusing on high-quality fiberglass sailboats to capitalize on the growing demand in the recreational boating market.^[77] The company expanded rapidly, introducing popular models such as the S2 7.9 Grand Slam, a one-design racer known for its competitive performance in regattas, and built a reputation for durable construction using hand-laid fiberglass hulls.^[78] By the early 1980s, S2 Yachts had grown to employ over 500 workers across facilities totaling more than 300,000 square feet, producing a range of sailboats from 22 to 41 feet alongside powerboats under brands like Pursuit.^[79] However, the company ceased sailboat production in 1989 amid industry shifts toward powerboats and economic challenges, eventually evolving into separate entities like Tiara Yachts, though the original S2 sailboat operations became defunct.^[77] S2 Analytical Solutions, LLC, is a veteran-owned government contracting firm established in March 2011 in Herndon, Virginia, specializing in digital engineering, model-based systems engineering, and data analytics to support Department of Defense (DoD) missions.^[80] The company delivers tailored solutions in cybersecurity, systems integration, and field testing, often operating in low-bandwidth and cross-domain environments to enhance operational effectiveness for federal clients.^[81] As a small business prime contractor on vehicles like GSA Multiple Award Schedule (MAS) and OASIS+, S2 Analytical has grown from one employee to 300 as of November 2025, emphasizing talent acquisition in engineering and IT to meet mission-critical requirements.^[82] Its work focuses on innovative processes that improve government operations without direct product development, maintaining a strong emphasis on security clearances and agile methodologies.^[83] The Services Society (S2) is a non-profit professional organization founded in the early 2010s to foster global collaboration in services computing, IT, and engineering among academia, industry, and government sectors.^[84] It promotes research and innovation through annual conferences such as the Services Conference Federation (SCF), International Conference on Web Services (ICWS), and specialized events on topics like cloud computing and big data, facilitating knowledge exchange via publications, certifications like Certified BigData Professional (CBDP), and standards development.^[85] With a membership model that includes researchers and practitioners, S2 emphasizes open technical collaboration to advance service-oriented architectures and emerging technologies, without commercial product ties.^[86]

Products

Cameras and optics

The Nikon S2 is a 35mm rangefinder camera produced by Nikon from December 1954 to June 1958, marking the first model in the S series to adopt the standard 24 × 36 mm film format for full-frame exposure.^[87] It featured a lightweight aluminum die-cast body, a coupled rangefinder with 1.0× magnification, and a cloth focal-plane shutter offering speeds from 1 to 1/1000 second plus B, compatible with Nikkor lenses such as the 50 mm f/1.4 and 105 mm f/2.5.^[88] As a professional-grade instrument, the S2 served as a direct predecessor to Nikon's shift toward SLR designs, culminating in the Nikon F in 1959, and emphasized precision engineering for photojournalism and studio work.^[89] The Fujifilm FinePix S2 Pro, released in 2002, was a digital SLR camera utilizing a 6.17-megapixel Super CCD SR sensor that effectively produced 12-megapixel images through dual-pixel architecture for enhanced dynamic range.^[90] Compatible with Nikon F-mount lenses, it offered 2 frames per second continuous shooting, ISO sensitivity up to 1600, and dual storage slots for CompactFlash and SmartMedia cards, positioning it as a bridge between film-era aesthetics and digital workflow for portrait and landscape photographers.^[90] The camera's innovative sensor technology prioritized natural color reproduction and low noise, distinguishing it from contemporary CMOS-based competitors.^[90] Canon introduced the PowerShot S2 IS in 2005 as a 5-megapixel digital compact camera with a 12× optical zoom lens equivalent to 36–432 mm in 35 mm terms, incorporating optical image stabilization to reduce blur in handheld shots.^[91] Featuring a 2.0-inch LCD, 30 fps VGA video recording, and a robust plastic body weighing 505 g, it targeted enthusiast users seeking versatile superzoom capabilities without interchangeable lenses.^[91] The S2 IS improved upon its predecessor, the S1 IS, with refined autofocus and exposure algorithms for better low-light performance and color accuracy.^[92] The Leica S2, launched in 2009, represented Leica's entry into medium-format digital photography with a 37.5-megapixel Kodak CCD sensor measuring 30 × 45 mm—56% larger than full-frame—for exceptional resolution and tonal gradation in professional applications.^[93] As part of a modular system, it included an autofocus mechanism, 1.5 fps burst rate up to 8 frames, ISO range from 80 to 1250, and compatibility with Leica S-mount lenses like the Summarit-S series, emphasizing weather-sealed construction for studio and field use.^[93] The camera's design integrated a dual-shutter system with in-body focal-plane options, underscoring Leica's commitment to high-fidelity imaging in advertising and fashion photography.^[94]

Electronics and devices

The Samsung Galaxy S II, released in 2011, was a landmark Android smartphone featuring a 1.2 GHz dual-core Exynos 4210 processor, which enabled smooth multitasking and early mobile gaming experiences.^[95] It included 1 GB of RAM and ran Android 2.3 Gingerbread with Samsung's TouchWiz interface, supporting expandable storage via microSD. The device achieved global sales exceeding 10 million units within its first five months, underscoring its commercial success and influence on the smartphone market. Its Super AMOLED Plus display, measuring 4.3 inches with 480 x 800 resolution, delivered vibrant colors and high contrast, while an 8 MP rear camera with autofocus and LED flash supported 1080p video recording, complemented by a 2 MP front camera for video calls.^[95] Connectivity options included HSPA+, Bluetooth 3.0, and NFC in select variants, with a 1650 mAh battery providing up to 18 hours of talk time.^[96] The Nikon 1 S2, introduced in 2014 as part of Nikon's compact mirrorless system, emphasized electronic performance through its 14.2-megapixel 1-inch CMOS sensor paired with the EXPEED 4A image processor, enabling ISO sensitivity up to 12,800 for low-light shooting.^[97] It supported continuous shooting at up to 20 frames per second with autofocus tracking, powered by a hybrid phase- and contrast-detection AF system with 135 focus points, which allowed for rapid capture of fast-moving subjects.^[98] The camera featured a 3-inch 460,000-dot LCD touchscreen for intuitive control and slow-motion video at 1080/60p, with built-in Wi-Fi via an optional adapter for wireless image transfer and remote operation.^[97] Its electronic shutter reached speeds of 1/16,000 second, minimizing distortion in high-speed sequences, while a magnesium alloy body weighed just 190 grams for portability.^[98] S2 access control systems, developed by S2 Security and now part of LenelS2 under Honeywell following Carrier's 2018 acquisition of S2 and Honeywell's 2024 acquisition of LenelS2 from Carrier, provide IP-based networked panels for enterprise-level building security management.^[99] These systems use modular controllers like the NetBox series, which support up to thousands of doors via Ethernet connectivity, integrating access control with video surveillance, intrusion detection, and environmental monitoring through open protocols such as BACnet and ONVIF.^[99] Key features include edge processing for real-time event handling and cloud-compatible software for remote administration, with 2025 updates to NetBox v6.2 enhancing AI-driven analytics for threat detection and seamless integration with IoT building automation systems.^[100] The platforms employ RFID and biometric readers, ensuring scalable deployment from small facilities to large campuses while maintaining compliance with standards like UL 294 for access control hardware.^[99]

Other uses

Fictional elements

In the anime series Neon Genesis Evangelion, the S² Engine, or Super Solenoid Engine, functions as a fictional perpetual motion device embedded within the core of each Angel, supplying them with boundless energy and rendering them effectively immortal until their core is destroyed. This organ enables the Angels to regenerate from severe damage and operate without external power sources, posing an existential threat to humanity's defenses in the post-apocalyptic world of the series. The concept draws on pseudoscientific ideas of infinite energy generation, emphasizing the Angels' otherworldly superiority and driving key conflicts, such as the battle against the ninth Angel, Zeruel, whose S² Engine is absorbed by Evangelion Unit-01, granting it autonomous power and berserk capabilities that alter the narrative trajectory.^[101] The S² Engine's role extends beyond mere power supply, symbolizing forbidden knowledge tied to the origins of life on Earth through the Seeds of Life, where it represents the "Fruit of Life" counterpart to humanity's limited "Fruit of Knowledge." In the original 1995 television series produced by Gainax, the Engine's extraction and integration into Evangelion units underscore themes of human hubris and the pursuit of godlike power, culminating in apocalyptic events like Third Impact. This element recurs in the Rebuild of Evangelion film tetralogy (2007–2021), directed by Hideaki Anno under Studio Khara, where revised Angel designs and Engine mechanics heighten the stakes in redesigned battles, such as those involving Sahaquiel and Armisael, while maintaining its core function as an unending energy source that blurs the line between biology and machinery.

Miscellaneous designations

In medicine, S2 designates the second heart sound, a normal component of the cardiac cycle produced by the closure of the aortic and pulmonic valves at the end of systole.^[5] This sound is typically heard as a single or split component during auscultation and can vary with respiration, providing diagnostic clues for conditions like pulmonary hypertension when altered.^[102] In anatomy, S2 refers to the second sacral vertebra, one of the five fused vertebrae forming the sacrum at the base of the spine.^[103] This vertebra contributes to the structural support of the pelvis and serves as an attachment point for ligaments and muscles involved in lower body stability and movement.^[104] In chemistry, S²⁻ denotes the sulfide ion, an anion formed by the addition of two electrons to a neutral sulfur atom, commonly found in salts like sodium sulfide and exhibiting strong basic properties in aqueous solutions.^[105] In computing, S2 represents a power management sleep state in the Advanced Configuration and Power Interface (ACPI) specification, where the system appears off, the CPU loses context, and RAM remains powered for quick resume, consuming less energy than the shallower S1 state but more than deeper modes like S3.^[106] In education systems such as Singapore's, S2 signifies Secondary 2, the second year of secondary schooling typically for students aged 13-14, focusing on foundational subjects like mathematics, sciences, and humanities to prepare for higher-level streaming.^[107]

References

[1]
Detection of the Schwarzschild precession in the orbit of the star S2 ...
The star S2 orbiting the compact radio source Sgr A* is a precision probe of the gravitational field around the closest massive black hole (candidate). Over the ...
[2]
The S-star cluster at the center of the Milky Way
Later, Martins et al. (2008) confined the spectral type of S2 to be a B0 − 2.5 V main-sequence star with a zero-age main-sequence (ZAMS) mass of 19.5 M⊙.
[3]
Nature of Fast-Moving Star S2 - IOP Science
Since we detect several of them, we can safely argue that S2 has a spectral type between B0 and B2.5. Figure 12 of Hanson et al. (2005) shows that in ...
[4]
Motion of "S2" and other stars around the central Black Hole - ESO
It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the ...
[5]
Dance around the heart of our Milky Way - Max-Planck-Gesellschaft
Apr 16, 2020 · The star S2 orbits the supermassive black hole on a rosette-shaped orbit and confirms Einstein's theory.
[6]
Sphere -- from Wolfram MathWorld
As a result, geometers call the surface of the usual sphere the 3-sphere, while topologists refer to it as the 2-sphere and denote it S^2 . Regardless of ...
[7]
2-sphere in nLab
May 10, 2025 · The 2-sphere S 2 S^2 is the ordinary sphere of dimension 2 2 , hence the n n -sphere for n = 2 n = 2 . Equipped with its canonical complex ...
[8]
Spherical Coordinates -- from Wolfram MathWorld
Spherical coordinates are a system for describing positions on a sphere, using r (distance), theta (azimuthal angle), and phi (polar angle).
[9]
Henri Poincaré - Stanford Encyclopedia of Philosophy
Sep 3, 2013 · Poincaré is also famous for his 1904 conjecture concerning the topology of three-dimensional spheres which remained one of the major unsolved ...
[10]
[PDF] 1. Representations of SL(2, R) These notes describe the irreducible ...
These notes describe the irreducible representations of the group G = SL(2, R) of two by two real matrices of determinant one. The ideas go back mostly to ...
[11]
The Second Heart Sound - Clinical Methods - NCBI Bookshelf - NIH
The high prevalence of expiratory splitting of S2 in cardiomyopathy may be explained by a combination of low cardiac output, mitral regurgitation, pulmonary ...Definition · Technique · Basic Science
[12]
Heart Sounds Topic Review - Healio
Second Heart Sound (S2) The A2 sound is normally much louder than the P2 due to higher pressures in the left side of the heart; thus, A2 radiates to all ...S1 Heart Sound · S2 Heart Sound · S3 Heart Sound
[13]
Heart Sounds - Medscape Reference
Oct 22, 2024 · The second heart sound (S2) is produced by the closure of the aortic (A2) and the pulmonary valves (P2) at the end of systole. ... Refer to the ...
[14]
Cardiology - Heart Sounds and Murmurs
Jul 7, 2017 · The second heart sound (S2) represents closure of the semilunar (aortic and pulmonary) valves (point d). S2 is normally split because the ...
[15]
Paradoxically split S2 heart sound - Healio
A paradoxical split S2 heart sound occurs when the splitting is heard during expiration and disappears during inspiration, the opposite of the physiologic ...
[16]
Second Heart Sound
Apr 7, 2020 · The auscultation of second heart sound reveals presence of the disease and its pathophysiology, conduction defects, ventricular function, and hemodynamics.
[17]
Structural and functional properties of SARS-CoV-2 spike protein
Aug 3, 2020 · The spike (S) protein of SARS-CoV-2, which plays a key role in the receptor recognition and cell membrane fusion process, is composed of two ...
[18]
Structure, Function, and Antigenicity of the SARS-CoV-2 Spike ...
Apr 16, 2020 · S comprises two functional subunits responsible for binding to the host cell receptor (S1 subunit) and fusion of the viral and cellular ...
[19]
Severe acute respiratory syndrome coronavirus (SARS-CoV ... - PNAS
S2 contains two heptad repeat regions (shaded bars), HR1 and HR2, as indicated. (B) clustalw multiple sequence alignment of coronavirus spike proteins. Shown is ...
[20]
A variant-proof SARS-CoV-2 vaccine targeting HR1 domain in S2 ...
Nov 10, 2022 · The S2 subunit contains two important domains, heptad repeat 1 (HR1) and heptad repeat 2 (HR2), which are highly conserved among coronaviruses.
[21]
Evolving SARS-CoV-2 Vaccines: From Current Solutions to Broad ...
The more conserved S2 subunit represents a promising target for broad-spectrum antibody development against a broader range of coronaviruses, including both ...
[22]
S2 Peptide-Conjugated SARS-CoV-2 Virus-like Particles Provide ...
Jun 18, 2024 · This study aimed to design a next-generation vaccine that provides broader protection against diverse coronaviruses, focusing on glycan-free S2 peptides as ...
[23]
Common cold embecovirus imprinting primes broadly neutralizing ...
Oct 9, 2025 · The S2 subunit of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike is highly conserved across coronavirus strains and ...
[24]
Broad-spectrum coronavirus vaccines: integrated strategies to ...
Ng et al. demonstrated through murine immunization studies that S2 subunit immunization elicited broader neutralizing antibody responses against SARS-CoV-2 ...
[25]
Phases of the cell cycle (article) - Khan Academy
In S phase, the cell synthesizes a complete copy of the DNA in its nucleus. It also duplicates a microtubule-organizing structure called the centrosome.
[26]
An Overview of the Cell Cycle - Molecular Biology of the Cell - NCBI
DNA duplication occurs during S phase (S for synthesis), which requires 10–12 hours and occupies about half of the cell-cycle time in a typical mammalian cell.Missing: developmental | Show results with:developmental
[27]
Use of Drosophila S2 Cells for Live Imaging of Cell Division - JoVE
Aug 23, 2019 · Drosophila S2 cells are an important tool in studying mitosis in tissue culture, providing molecular insights into this fundamental cellular ...
[28]
Ecdysone signaling induces two phases of cell cycle exit in ...
Nov 15, 2016 · Summary: Pulsed ecdysone signaling remodels cell cycle dynamics, causing distinct primary and secondary cell cycle arrests in Drosophila ...
[29]
google/s2geometry: Computational geometry and spatial ... - GitHub
This is a package for manipulating geometric shapes. Unlike many geometry libraries, S2 is primarily designed to work with spherical geometry.
[30]
S2 Geometry | S2Geometry
A unique feature of the S2 library is that unlike traditional geographic information systems, which represent data as flat two-dimensional projections (similar ...OverviewS2 CellsDeveloper GuideQuick StartAbout S2
[31]
Announcing the S2 Library: Geometry on the Sphere
Dec 5, 2017 · The S2 library is Google's core geometric library for its geographic database, representing data on a 3D sphere, unlike traditional 2D systems.
[32]
Spherical Geometry Operators Using the S2 Geometry Library
The s2 R package provides bindings to Google's S2Geometry library. The package exposes an API similar to Google's BigQuery Geography API, whose functions ...
[33]
google/s2-geometry-library-java: Automatically exported ... - GitHub
This is a package for manipulating geometric shapes. Unlike many geometry libraries, S2 is primarily designed to work with spherical geometry.<|separator|>
[34]
A Benchmark and Evaluation System for Author Name Disambiguation
Mar 12, 2021 · We present S2AND, a unified benchmark dataset for AND on scholarly papers, as well as an open-source reference model implementation.
[35]
A Benchmark and Evaluation System for Author Name Disambiguation
This work presents S2AND, a unified benchmark dataset for AND on scholarly papers, as well as an open-source reference model implementation, and releases ...
[36]
allenai/S2AND: Semantic Scholar's Author Disambiguation ... - GitHub
This repository provides access to the S2AND dataset and S2AND reference model described in the paper S2AND: A Benchmark and Evaluation System for Author Name ...
[37]
A Benchmark and Evaluation System for Author Name Disambiguation
Sep 13, 2024 · Our dataset harmonizes eight disparate AND datasets into a uniform format, with a single rich feature set drawn from the Semantic Scholar (S2) ...
[38]
The S2 Automated Agent (S2A2): A Training Aid for ... - DTIC
S2A2 is an automated agent that models an S2 officer's functions, allowing commanders to implement war plans and receive intelligence reports in a simulation.
[39]
[PDF] the s2 automated agent (s2a2): a training aid for commanders - DTIC
The functions of an S2 automated agent could also be used with currently fielded Army systems to help an intelligence officer rapidly analyze information and ...
[40]
Detection of the gravitational redshift in the orbit of the star S2 near ...
S2 reached pericentre of its orbit at the end of April 2002, and then again on May 19th, 2018 (MJD 58257.67). The data before 2017 are taken from Ghez et al. ( ...
[41]
Relativistic redshift of the star S0-2 orbiting the Galactic Center ...
Do et al. monitored the position and spectrum of the star S0-2 as it passed Sagittarius A*, the supermassive black hole at the center of the Milky Way.
[42]
Hydrogen 1S-2S Transition - MPQ
The lifetime of the metastable 2S state is 0.12 seconds, which is about 8 orders of magnitude longer than the lifetime of the 2P level. The resulting linewidth ...
[43]
Precision spectroscopy of the hyperfine components of the 1S–2S ...
Jan 17, 2025 · Here we report on the simultaneous observation of both accessible hyperfine components of the 1S–2S transition in trapped antihydrogen.
[44]
Early Polish Cars - Team.Net
In 1927 Jan Laski established the firm named Towarzystwo Budowy Samochod ów AS (The AS Automobile Company). The factory located in Warsaw at 64 Zlota Street ...
[45]
AUDI Coupe S2 quattro (1990-1996) Photos, engines & full specs
The Audi Coupe S2 quattro, produced 1990-1996, is a two-door, all-wheel drive coupe with a 2.2L turbocharged inline-five engine, 220 HP, and a 6.1s 0-62 mph ...
[46]
1990 Audi Coupe S2 B3 8B full range specs - Automobile Catalog
3-door coupe body type, 4x4 full-time (quattro 2gen, all-wheel drive permanent; torsen center differential 50/50 (75/25-25/75 automatically distributed), ...
[47]
Audi 80 (B3/B4) S2 Quattro Specs, Performance, Comparisons
Audi 80 (B3/B4) S2 Quattro Specs ; Compression Ratio : 9.3 ; Horsepower : 227 HP / 230 PS / 169 kW @ 5900 rpm ; Maximum torque : 258 lb-ft / 350 Nm @ 1950 rpm.
[48]
2001 Lotus Elise Series 2 full range specs - Automobile Catalog
2-door roadster body type, RWD (rear- wheel drive), manual 5-speed gearbox, gasoline (petrol) engine with displacement: 1795 cm3 / 109.7 cui.
[49]
Lotus Elise S2 111 S Specs, Performance, Comparisons
The Lotus Elise S2 111 S has a Inline 4, Petrol engine with 1796 cm3 / 109.6 cu-in capacity. How many horsepower (hp) does a 2002 Lotus Elise S2 111 S have? The ...
[50]
LOTUS Elise Models/Series Timeline, Specifications & Photos
Jan 10, 2024 · The engine was the same 1.8-liter supercharged four-mill tuned to provide 240 hp. Yes, the Final Edition Sport 240 was heavier than the original ...
[51]
Model Overview 944 | Porsche Classic
The 944 S2's 3.0-litre four-valve engine delivered 211 PS and also brought the S successor close to the Turbo model in terms of performance. The 944 S2 was also ...
[52]
Porsche 944 S2 Coupe (1989 - 1991) - Stuttcars
Peak power was 208 bhp @ 5800 rpm and torque was 207 lb-ft @ 4100 rpm. Performance wise, the 944 S2 was good for 6.90 second 0-60 mph time and a 14.9 second ...
[53]
Collectible Classic: 1989-1991 Porsche 944 S2 - MotorTrend
Jan 31, 2017 · Engine. 3.0L DOHC I-4/208 hp @ 5,800 rpm, 207 lb-ft @ 4,100 rpm ; Transmission. 5-speed manual ; Drive. Rear-wheel ; Front Suspension. Struts, coil ...
[54]
Poland's longest road tunnel opens in Warsaw
Dec 20, 2021 · The S2 southern ring road runs 33 kilometres, with its final stretch of 4.6 kilometres between Puławska street and the Wilanów district added ...<|control11|><|separator|>
[55]
California's Desert Highway S-2 | FHWA
Jun 30, 2023 · Highway S-2 is a desert road in south-central California with a fascinating history. Beginning at California Highway 79 near Warner Springs.
[56]
Driving in Georgia - Tbilisi - Georgian Travel Guide
Mar 30, 2022 · Here is the list of 13 roads of international importance that cross the territory of Georgia: S1 - Tbilisi - Senaki - Leselidze (552 km); S2 ...
[57]
S2 bus route - Transport for London
Towards St Helier Station · Epsom High Street · Rainbow Leisure Centre · Kiln Lane · Windmill Lane · Hessle Grove · Mongers Lane · Reigate Road / Green Man · Hazel Mead.Towards Epsom · Epsom Clock Tower · Sutton / Marshall's Road · York Road
[58]
Taking a ride on Epsom's new S2 bus ›
Apr 6, 2024 · The bright LED numbering and hum that come with all-electric vehicles suggested TfL was taking bus travel seriously in South London. Once ...
[59]
S2 | S-Bahn Berlin GmbH
Line properties ; Distance of the line:46,4 km ; Duration74 Minutes ; Number of train stations on the line:28 train stations.Missing: Bundesstraße | Show results with:Bundesstraße
[60]
The S-Bahn Berlin S2 - Transit
+ Potsdamer Platz Bhf3:24 PM; + Brandenburger Tor3:26 PM; + ... S-Bahn Berlin S2 s-bahn Service Frequency. Trips every 10 min. The next S2 s-bahn ...
[61]
Imperial/San Diego County Sign Route S2 - California Highways
Cty Rte S2 · Imperial Highway from County Road 2A02 to the San Diego county line (FAS, 7.40 mi) [Imperial County] · Sweeney Pass Road from the Imperial county ...
[62]
[PDF] Grumman S-2 Tracker - MAPS Air Museum
The Grumman S-2 Tracker (previously S2F prior to 1962) was the first purpose-built, single airframe anti-submarine warfare. (ASW) aircraft to enter service with ...
[63]
Grumman S-2E/G Tracker - Sea Power Centre
Specifications ; Wing span: 72 feet 7 inches · 265 mph · 9 hours · 4 · Two Wright Cyclone engines each developing 1520 hp.
[64]
Grumman S-2 Tracker (S2F) Anti-Submarine Warfare (ASW) Aircraft
Page details technical specifications, development, and operational history of the Grumman S-2 Tracker (S2F) Anti-Submarine Warfare (ASW) Aircraft including ...
[65]
S-2 Tracker Tanker 84 | Pacific Coast Air Museum | CDF Fire Fighter
Originally designated the S2F Tracker, several versions were eventually built that included the original anti-submarine, an electronics measures version and a ...
[66]
Tag Archives: Short Biplane No. 2 - This Day in Aviation
It was the first company to build production airplanes. The Short Biplane No. 2 was designed by Horace Leonard Short. It was similar to the Wright Brothers ...
[67]
Short Biplane No.2 / No.3 - Their Flying Machines
Short S.2 on which Moore-Brabazon won the Daily Mail prize for a circular flight of one mile in October 1909. plane photo ...
[68]
None
Below is a merged summary of the S-2 Sounding Rocket information based on the provided segments. Since the document does not consistently or explicitly define an "S-2" as a standalone sounding rocket, the information is synthesized from general NASA Sounding Rocket Program (SRP) context and any specific references to an "S-2" (e.g., as a stage of the Aries rocket or a component). The response includes all details from the summaries, organized for clarity and density, with a table in CSV format to capture specifications and other detailed data efficiently.
[69]
Rocket, Second Stage, S-II-F/D Dynamic Test Vehicle, Saturn V
The S-II-F/D is the second stage of the Saturn V, used for ground tests, not for flight, and was important in the Apollo program. It is not on display.
[70]
75 Years Ago: First Launch of a Two-Stage Rocket - NASA
May 12, 2023 · The first two-stage liquid-fueled rocket launch predated the Space Age by nearly a decade, taking place on May 13, 1948, at the White Sands Proving Ground ( ...
[71]
Pennsylvania 6200 turbine locomotive - Trains Magazine
Jun 30, 2023 · The sole member of PRR class S2 was completed in September 1944 with a 6-8-6 wheel arrangement, rather than 4-8-4 as first planned. It burned ...
[72]
Pennsylvania O Gauge RailKing 6-8-6 Imperial S-2 Turbine Steam ...
The 6900 hp S2 was more powerful, had a higher top speed (110 mph) and cost half as much. And it was handsome: massive boiler; 6-wheel leading and trailing ...Missing: maximum | Show results with:maximum
[73]
Alco S-2 roster - The Diesel Shop
Jan 9, 2021 · Road Numbers, Qty. Bldr Numbers, Bldr Dates. Akron Canton & Youngstown, 101, 1, 69674, 5/1942. Alton RR, 10 - 13, 4, 72004-72007, 2/1944. 14 - ...Missing: production | Show results with:production
[74]
DB to upgrade 130 km of track on Anhalter Bahn
Sep 5, 2025 · They include the installation of 33 new switches and the refurbishment of a further 59. Around 100 km of track will be completely renewed, with ...
[75]
Low-floor S-Bahn lines in the ZVV
Line, Route*, Low floor wagons, Type of low floor wagons. S2, Zürich Flughafen–Zürich HB–Pfäffikon SZ–Ziegelbrücke, on all connections, low-floor entrances ...
[76]
The SBB online portal for timetable, trains and public transport
One simple pass for train, bus and boat travel in Switzerland. Buy Swiss Half Fare Card Get half off train, bus and boat fares in Switzerland.PDF timetables · Tickets for Switzerland · Supersaver tickets · Excursion ideasMissing: S2 | Show results with:S2
[77]
#Reviewing World War I and the Origins of U.S. Military Intelligence
Jun 12, 2017 · The origins of U.S. Military Intelligence is the story of the efforts of two men, Dennis E. Nolan and Ralph Van Deman.Missing: formalization | Show results with:formalization
[78]
[PDF] TC 2-50.5 Intelligence Officer's Handbook January 2010
Jan 6, 2010 · RESPONSIBILITIES. F-1. The intelligence officer is responsible for weather intelligence. The G-2/S-2 is supported by a U.S.. Air Force staff ...
[79]
Guide for Participants in Peace, Stability, and Relief Operations
Section 1 (S1) handles personnel administration; S2 handles the processing of intelligence and tactical information for the commander; S3 handles plans, ...
[80]
Pantsir-S2 - Army Recognition
Aug 30, 2025 · The Pantsir-S2 can launch new surface-to-air missiles which increases the range from 20 to 30 km. The Pantsir-S2 is also fitted with a new SOTS ...Description · Technical Data · Specifications
[81]
This S-2 Tracker Is The Last Of Its Kind In Military Use - The War Zone
Jul 17, 2025 · It was developed for the U.S. Navy as a carrier-based anti-submarine warfare aircraft and entered service in 1954. Compared to its predecessors, ...Missing: adaptations | Show results with:adaptations
[82]
Argentine Trackers: The world's last Grumman S-2s - Key Aero
Aug 10, 2021 · The Argentine Navy is the world's last military operator of the turbine equipped Grumman S-2 Tracker, with a single example still being used for ASW and SAR ...Missing: adaptations | Show results with:adaptations
[83]
S2 Yachts (USA) - SailboatData.com
S2 Yachts, founded by Leon Slikkers in Holland, Michigan, built sailboats from 1974-1989, and later powerboats. Sailboat production ended in 1989.Missing: history | Show results with:history
[84]
Shifting Sands: The story of S2 Yachts - Power & Motoryacht
Jul 13, 2020 · S2 Yachts started from Chris-Craft scraps, now a high-performance yacht maker, founded by Leon Slikkers, and is now a family business.Missing: manufacturer | Show results with:manufacturer
[85]
S2 History - Angelfire
S2 Yachts, Inc. History 1974. Beginning of S2 Yachts, Inc., manufacturer of sailboats, 72,000 sq.ft., 53 employees 1977. Introduction of Pursuit series
[86]
About Us - S2 Analytical Solutions
S2 Analytical Solutions was founded in March 2011 with one employee, one contract, and one customer. By attracting and delivering the top talent in the market.
[87]
S2 Analytical Solutions: Home
We use digital engineering, model-based system engineering and field testing to deliver solutions that work cross domains, in low bandwidth environments and ...Careers · Company · Contact · Leadership
[88]
Contract Vehicles - S2 Analytical Solutions
S2 is a prime contractor on multiple Government-Wide Acquisition Contracts, including GSA MAS and GSA OASIS+. S2 is also a JV Prime (as mentor) on GSA OASIS+.
[89]
S2 Analytical Solutions, LLC - LinkedIn
S2 Analytical Solutions is a veteran-owned business focused on providing skilled engineers and integrators to meet mission critical requirements across the DOD ...
[90]
Home — Services Society (S2)
Services Society (S2) · About · Guides · Instructions · Submission · Registration · Presentation · Sponsorship · Conferences · SCF Overview · ICWS 2025 · SCC ...
[91]
Membership — Services Society (S2)
The Services Society (S2) is a non-profit professional organization that has been created to promote worldwide research and technical collaboration in ...
[92]
Services Society | LinkedIn
The Services Society (S2) is a non-profit professional organization that has been created to promote worldwide research and technical collaboration in ...Missing: engineering | Show results with:engineering
[93]
Vol. 8. Nikon S2 | Camera Chronicle
The Nikon S's film image size was 24 x 34mm. The width was increased to approximately 36mm, bringing it close to the world standard. This increase meant that ...A Lens Mounting Dispute · A Total Makeover Of The... · Progress With Viewfinder...<|control11|><|separator|>
[94]
Nikon S2 Rangefinder - NikonWeb.com
The S2 was the first Nikon camera to use a standard 24x36mm film format. Earlier models used a slightly smaller 24x32mm (Nikon I) and 24x34mm (Nikon M and S) ...Missing: 1954-1958 | Show results with:1954-1958
[95]
Nikon S2 | LENS-DB.COM
35mm MF film rangefinder camera • Discontinued · Announced: · December 1954 · Production status: · Discontinued · Country of design: · Japan · System: · Nikon S (1947) ...
[96]
Fujifilm FinePix S2 Pro Review - DPReview
Rating 4.3 (118) Aug 3, 2002 · The S2 Pro has a 6.17MP SuperCCD sensor producing 12MP images, a new body, high ISO, 2fps shooting, and dual media slots.
[97]
Canon PowerShot S2 IS Review - DPReview
Rating 4.3 (166) Jun 21, 2005 · The S2 IS is not only better specified than its predecessor; it's larger (much deeper) and heavier too. Most of this is down to the slightly larger sensor.
[98]
Canon PowerShot S2 IS: Digital Photography Review - DPReview
Apr 22, 2005 · This worthy successor to the PowerShot S1 IS features optical Image Stabilizer technology, outstanding optics and 30 fps digital video camera quality.
[99]
Leica S system specifications: Digital Photography Review
Aug 16, 2009 · The S2 as a 37.5 megapixel Kodak CCD sensor which measures 45 x 30 mm, sensitivity is pegged from ISO 80 to 1250 and the camera can shoot 1.5 fps for up to 8 ...
[100]
Leica reveal S-system pricing and launch date - DPReview
Jul 30, 2009 · The camera is built around a 37.5 megapixel 30x45mm sensor (56% larger than 'full frame'), that puts it squarely into the apparently troubled ...
[101]
Samsung I9100 Galaxy S II - Full phone specifications
Samsung I9100 Galaxy S II ; Type, Super AMOLED Plus ; Size, 4.3 inches, 52.6 cm2 (~63.5% screen-to-body ratio) ; Resolution, 480 x 800 pixels, 5:3 ratio (~217 ppi ...
[102]
GALAXY S II - Samsung Mobile Press
The Galaxy S II has GSM network, Android 2.3, 4.27" display, 1 GHz dual core processor, 8MP rear and 2MP front cameras, 16/32GB microSD, and 1650mAh battery.
[103]
Nikon 1 S2 full specifications: Digital Photography Review
Body type. Body type, Rangefinder-style mirrorless. Sensor. Image ratio w:h, 3:2. Sensor size, 1″ (13.1 x 8.8 mm). Sensor type, CMOS. Processor, Expeed 4A.
[104]
Advanced Camera with Interchangeable Lenses Nikon 1 S2 | News
May 14, 2014 · At approximately 20 fps, the S2 achieves the world's fastest* continuous shooting rate with AF tracking. An even shorter shooting time lag, ...Missing: burst | Show results with:burst
[105]
UTC Climate, Controls & Security Completes Acquisition of S2 ...
Oct 2, 2018 · UTC Climate, Controls & Security has completed its acquisition of S2 Security, which will be combined with Lenel, to create LenelS2, a global leader in ...
[106]
LenelS2 | The Leading Physical Security Company
LenelS2 offers advanced physical security products for access control, video surveillance, & mobile credentialing for organizations of all sizes.Access Control · Access Control Training · Security Solutions · Security Consultants
[107]
LenelS2, No. 1 Global Access Solutions Provider, Releases Next ...
Jan 30, 2023 · LenelS2, No. 1 Global Access Solutions Provider, Releases Next Generation of NetBox Access Control Software. January 30, 2023.
[108]
Perpetual-Motion Monster - TV Tropes
The Angels in Neon Genesis Evangelion are explicitly stated to have an infinite power source in their bodies: the S2 Organ. Therefore, while alive, they ...
[109]
Cardiac Second Heart Sounds - Stanford Medicine
There are believed to be multiple causes for the physiologic splitting of S2. Both A2 and P2 close when the pressure above the respective valves are greater ...
[110]
Vertebra S2 - e-Anatomy - IMAIOS
The second sacral vertebra (S2) is part of the sacrum, which is formed by the fusion of five sacral vertebrae. The S2 vertebra has several key anatomical ...
[111]
Anatomy, Back, Sacral Vertebrae - StatPearls - NCBI Bookshelf
The vertebral column, or spine, is composed of 33 vertebrae. These vertebrae play an essential role in protecting the spinal cord and the spinal nerves.
[112]
Sulfide Ion (S²⁻) - Chemistry LibreTexts
Aug 29, 2023 · Sulfide is a strong base, so solutions of sulfide in water are basic, due to hydrolysis. Sulfide solutions develop the characteristic rotten-egg ...
[113]
System Sleeping States - Windows drivers | Microsoft Learn
May 1, 2025 · States S1, S2, S3, and S4 are the sleeping states. A system in one of these states is not performing any computational tasks and appears to be off.
[114]
Secondary school experience under Full SBB - MOE
Jun 12, 2025 · From Secondary 2 (S2), students will also be able to offer Humanities subjects (Geography, History, and Literature in English) at a more ...