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Space Library The Satellite & Orbital Encyclopedia

Your comprehensive database of everything in orbit — 177+ pages of live trackers, upcoming launch schedule, visibility guides, real-time statistics, debris event archives, satellite profiles, country fleet data, space agency profiles, satellite internet comparisons, spaceports, space weather guides, launch vehicle profiles, spacecraft, space missions, space policy and the orbital glossary.

Last updated: · Sources: Space-Track, CelesTrak, UCS, ESA DISCOS

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44,870
Catalogued Objects
14,200
Active Satellites
Starlink Active
15,800+ t
Mass in Orbit

Powered by Orbital Radar · Live Data  —  Sources: Space-Track, CelesTrak

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Humans in Orbit
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Satellite of the Day
Orbital Radar in Numbers
44,870
Objects Tracked
14,200
Active Satellites
Starlink Active
175+
Library Pages
Humans in Space
15,800+ t
Mass in Orbit

Live Trackers

9 pages

Real-time satellite tracking powered by TLE data from Space-Track and CelesTrak. Follow the ISS, Starlink trains, space telescopes, navigation constellations, and debris objects as they orbit Earth. Each tracker shows live position, altitude, speed and orbital path — updated every second using SGP4 propagation.

This Week in Space

Auto-updated

Latest space industry headlines aggregated from leading sources — launches, missions, policy, debris events and commercial space. Updated automatically throughout the day. See also: upcoming launch schedule.

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Launch Schedule

Live · 1 page

Upcoming orbital launches from SpaceX, Rocket Lab, ULA, Arianespace, ISRO and others — auto-updated from Launch Library 2. Countdown timers, mission details, launch providers and pad locations for every mission in the next 30 days.

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Visibility Guides

8 pages

Everything you need to see satellites with your own eyes. Timing tips, camera settings, brightness rankings and the answer to "what is that moving light in the sky?" Most satellites are visible within 1–2 hours after sunset or before sunrise, when the sky is dark but objects in orbit are still lit by the Sun.

Live Statistics & Data

8 pages

Up-to-date numbers on the orbital environment: satellite counts by country and operator, launch rates, debris statistics and object classification breakdowns — sourced from Space-Track, UCS and ESA DISCOS. As of 2026, there are approximately 14,200 active satellites and 44,870 total tracked objects in Earth orbit.

Active Satellites (2016 → 2026)
2016: ~1,4002020: ~3,3002023: ~8,0002026: ~14,200

Space Reference

16 pages

In-depth explainers on the orbital environment — from orbital mechanics and debris physics to ASAT weapons, mega-constellations, and active debris removal technologies. Written for both newcomers and professionals, each guide covers the science, the data and the real-world implications for satellites and spaceflight.

🎓Orbital Academy — Learn orbits, TLEs, debris & conjunctions in focused slide-deck lessons

Satellite Internet & Broadband

6 pages

Mega-constellations are rewriting the rules of global internet access. Detailed comparisons of Starlink, Amazon Kuiper, OneWeb, and China's Guowang/Qianfan — covering speed, latency, coverage, pricing and satellite counts as of 2026. Starlink leads with roughly 9,850 active satellites delivering 25–220 Mbps to users in 70+ countries.

Quick Comparisons

Auto-generated

Side-by-side data tables comparing major constellations, navigation systems, and launch vehicles — auto-generated from Orbital Radar's live database.

LEO Broadband Constellations
Comparison of major LEO broadband satellite constellations as of 2026
ConstellationOperatorActive SatsAltitudeSpeedLatency
StarlinkSpaceX~9,850550 km25–220 Mbps25–60 ms
OneWebEutelsat6481,200 km50–195 Mbps32–45 ms
KuiperAmazonDeploying590–630 kmTBDTBD
GuowangChina SatNetDeploying500–1,145 kmTBDTBD
Global Navigation Systems (GNSS)
Comparison of global navigation satellite systems (GNSS)
SystemOperatorSatellitesAltitudeAccuracyCoverage
GPSUS Space Force3120,180 km~0.3 mGlobal
GalileoEU/ESA3023,222 km~0.2 mGlobal
GLONASSRoscosmos2419,130 km~2.8 mGlobal
BeiDouCNSA4521,528 km~3.6 mGlobal (Asia-Pacific optimised)
Super Heavy-Lift Rockets
Comparison of current and next-generation heavy-lift launch vehicles
VehicleOperatorLEO CapacityStatusReusable
StarshipSpaceX150,000 kgFlight testingFully
SLS Block 1NASA95,000 kgOperationalNo
Falcon HeavySpaceX63,800 kgOperationalPartial
New GlennBlue Origin45,000 kgOperationalPartial
Long March 5CASC25,000 kgOperationalNo
Ariane 6ArianeGroup21,650 kgOperationalNo

Space Weather

4 pages

How solar activity shapes the orbital environment — from geomagnetic storms that drag satellites out of orbit to solar radio bursts that disrupt GPS. Guides for operators, aurora watchers and anyone who depends on space-based infrastructure.

🎓Academy: Space Weather — KP index, solar wind, CMEs & auroras in 6 slide-deck lessons

Launch Vehicles & Spacecraft

17 profiles

Profiles of the rockets and spacecraft that define modern spaceflight — payload capacity, flight history, reusability, crew capability and key specifications as of 2026. From record-setting workhorses to next-generation super heavy-lift vehicles and crewed capsules. SpaceX's Falcon 9 alone has completed over 400 missions, while Starship is the largest and most powerful rocket ever built.

🎓Academy: Launch → Orbit — How rockets reach orbit, parking orbits & early-orbit chaos
Falcon 9
The world's most-flown orbital rocket — 400+ missions, 95%+ of global commercial launches
🔥 Popular
Falcon Heavy
SpaceX's triple-core heavy-lift rocket — most powerful operational launch vehicle, 63,800 kg to LEO
Starship
SpaceX's fully reusable super heavy-lift system — the largest and most powerful rocket ever flown
SLS — Space Launch System
NASA's super heavy-lift rocket for Artemis — 95,000 kg to LEO, launched Artemis I around the Moon
New Glenn
Blue Origin's heavy-lift orbital rocket — reusable first stage, 45,000 kg to LEO, Kuiper deployment vehicle
New Shepard
Blue Origin's reusable suborbital vehicle — crewed tourism flights to 100 km altitude and research payloads
Long March 5B
China's heavy-lift launcher — built Tiangong, notorious for uncontrolled core stage re-entries
Ariane 6
Europe's next-generation launcher — restoring independent European access to space
Soyuz
The most-launched rocket family in history — 2,000+ flights since 1966
PSLV
India's workhorse — ISRO's reliable medium-lift launcher with 60+ missions
Electron
Rocket Lab's small-sat launcher — dedicated rides to orbit for the small satellite market
Vulcan Centaur
ULA's next-gen rocket — BE-4 engines, Centaur V upper stage, replacing Atlas V and Delta IV
🆕 New
H3
Japan's flagship launcher — JAXA/MHI, LE-9 engines, designed to halve launch costs
🆕 New
Vega-C
Europe's lightweight launcher — complements Ariane 6, shares P120C booster
🆕 New

Crewed Spacecraft & Capsules

The crewed vehicles that carry astronauts to the ISS, the Moon and beyond — including commercial crew capsules like SpaceX Dragon and NASA's deep-space Orion.

Spaceports & Launch Sites

12 profiles

Every major launch facility on Earth — from the historic pads at Cape Canaveral and Baikonur to the newest vertical launch complexes in Shetland and Arctic Sweden. Location, coordinates, orbital access, active pads, operators and launch history.

Kennedy Space Center
Cape Canaveral, Florida — Apollo, Shuttle, Falcon 9/Heavy, SLS and Starship's east coast home
Vandenberg Space Force Base
California — primary US site for polar and sun-synchronous orbits, SpaceX and ULA pads
Starbase (Boca Chica)
South Texas — SpaceX's Starship development and launch facility, home of the world's largest rocket
Baikonur Cosmodrome
Kazakhstan — the world's first spaceport, launched Sputnik, Gagarin and still operates Soyuz today
Guiana Space Centre (Kourou)
French Guiana — Europe's spaceport at 5°N, ideal for GEO, home of Ariane 6 and Vega-C
Jiuquan Satellite Launch Center
Gobi Desert — China's oldest and most active spaceport, Shenzhou crewed missions and LEO launches
Wenchang Space Launch Site
Hainan Island — China's newest and most southerly site, Long March 5/7, Tiangong and lunar missions
Satish Dhawan Space Centre
Sriharikota, India — ISRO's primary launch site for PSLV, GSLV, Chandrayaan and Gaganyaan
Vostochny Cosmodrome
Russian Far East — Russia's new sovereign spaceport, reducing dependence on Baikonur
Rocket Lab LC-1 (Māhia)
Māhia Peninsula, New Zealand — world's first private orbital launch site, Electron's primary pad
SaxaVord Spaceport
Unst, Shetland — Europe's first licensed vertical launch site, polar orbit access from the UK
Esrange Space Center
Kiruna, Sweden — Arctic launch site, sounding rockets since 1966, developing orbital capability

Debris Event Archive

7 events

Detailed case studies of the most significant fragmentation and debris events in spaceflight history — from the 2007 Fengyun-1C ASAT test to the 2024 Resurs-P1 break-up. Each page includes key facts, fragment counts, orbital persistence data and FAQs. Together, these events produced over 10,000 trackable debris fragments still orbiting Earth.

🎓Academy: Debris & Re-entry — What debris is, why it's dangerous & how re-entries are predicted

Satellite Profiles

11 profiles

In-depth profiles of the most significant individual satellites and programmes — including the ISS, Hubble, James Webb Space Telescope and more. Orbital parameters, key facts, operational status as of 2026, and links to live tracking data.

Countries & Operators

19 profiles

Profiles of the major spacefaring nations and commercial satellite operators — fleet sizes, key constellations, launch capabilities, and strategic programmes as of 2026. From the United States and China to commercial giants like SpaceX and Planet Labs.

United States
10,000+ satellites — the world's largest fleet, dominated by Starlink
China
900+ satellites — fastest-growing programme, Guowang/Qianfan deploying
Russia
GLONASS, military assets, and the Soviet legacy in orbit
United Kingdom
760+ satellites — third largest fleet via OneWeb and SSTL
India
ISRO's fleet — NavIC, INSAT, Cartosat and Chandrayaan lunar success
Japan
JAXA — QZSS navigation, ALOS imaging, ADRAS-J debris removal
European Union / ESA
Galileo, Copernicus/Sentinel, Eutelsat OneWeb and IRIS²
Canada
CSA — Canadarm legacy, RADARSAT constellation, Arctic monitoring and Artemis contributions
🆕 New
United Arab Emirates
Hope Mars orbiter, KhalifaSat, MBRSC — the Gulf's fastest-growing space programme
🆕 New
Australia
Launch sites, SSA partnerships, Earth observation and a growing commercial sector
🆕 New
SpaceX / Starlink
~9,850 active Starlink satellites — 65% of all active spacecraft in orbit
Amazon Kuiper
3,236-satellite LEO broadband constellation — deployment underway
Planet Labs
200+ small sats imaging the entire planet daily at 3 m resolution
OneWeb (Eutelsat)
648-satellite LEO broadband constellation at 1,200 km altitude
Rocket Lab
Electron launcher, Neutron in development, and a growing spacecraft manufacturing division
Iridium Communications
66-satellite LEO constellation providing global voice, data and IoT connectivity
SES
Major GEO and MEO operator — O3b mPOWER constellation for global broadband and enterprise
Intelsat
Pioneer of commercial satellite communications — 50+ GEO satellites serving media and connectivity worldwide
Viasat
ViaSat-3 ultra-high-capacity GEO satellites for broadband and in-flight connectivity worldwide

Space Agencies

10 profiles

Profiles of the world's major space agencies — budgets, fleet sizes, key programmes, crewed capabilities, launch infrastructure and strategic priorities as of 2026. From NASA's Artemis programme to ISRO's cost-effective interplanetary missions.

Human Spaceflight

2 pages

The people and missions of crewed spaceflight — from the complete astronaut directory to every ISS expedition crew since permanent habitation began in 2000. Records, milestones and the growth of commercial crew programmes.

Space Missions & History

18 pages

The defining missions of the space age — from the Mercury programme and Apollo Moon landings to the Space Shuttle era, Artemis, Mars rovers and deep-space probes. Mission profiles, timelines, crew rosters and key milestones.

Space Missions Hub
Complete index of crewed programmes, robotic exploration, space stations and commercial missions
Apollo Programme
17 missions, 12 humans on the Moon — the defining achievement of the space age
Space Shuttle Programme
135 missions, 5 orbiters, 30 years — built the ISS, launched Hubble, carried 355 people to orbit
Artemis Programme
NASA's return to the Moon — SLS, Orion, Starship HLS and the Lunar Gateway
Space Stations — Past, Present & Future
ISS, Tiangong, Mir, Skylab, and what comes next: Axiom, Orbital Reef, Starlab, ROSS
Mercury Programme
America's first human spaceflight programme — 6 crewed missions, 1961–1963
Gemini Programme
The bridge to the Moon — 10 crewed missions that perfected spacewalking, rendezvous and docking
Vostok & Voskhod
The Soviet firsts — Gagarin's orbit, Tereshkova's flight, and Leonov's first spacewalk
Shenzhou Programme
China's crewed spacecraft — from Yang Liwei's first flight to Tiangong station rotations
Skylab
America's first space station — 3 crews, 171 days of habitation, 1973–1974
Mir Space Station
The Soviet/Russian station that pioneered long-duration spaceflight — 15 years in orbit
ISS Assembly
How the International Space Station was built — 40+ assembly flights from 1998 to 2021
Mars Rovers & Landers
Sojourner, Spirit, Opportunity, Curiosity, Perseverance and Zhurong — exploring the Red Planet
Voyager Missions
The farthest human-made objects — still transmitting from interstellar space after 48+ years
Lunar Exploration
Every Moon mission — from Luna 2 to Artemis, Chang'e, Chandrayaan, SLIM and commercial landers
Deep-Space Probes
Cassini, Juno, New Horizons, Parker Solar Probe and the missions exploring our solar system
🆕 New
Commercial Crew
How SpaceX Dragon and Boeing Starliner ended US dependence on Soyuz for ISS crew transport
🆕 New
Space Tourism
Blue Origin, SpaceX Inspiration4, Axiom missions and the rise of commercial human spaceflight
🆕 New

More Reference & Industry

4 pages

Deeper dives into navigation constellations, Earth observation applications, the commercial space industry, and military satellite systems.

Space Economy & Industry Data

6 pages

How big is the space industry? Market sizes, growth projections, investment flows, government budgets and revenue data for the global space economy — from satellite manufacturing and launch services to debris removal and commercial broadband. The global space economy reached an estimated $626 billion in 2025 and is projected to exceed $1 trillion by 2034.

Space Policy & Regulation

3 pages

The treaties, guidelines and agencies that govern what happens in orbit — from the foundational 1967 Outer Space Treaty to the FCC's new 5-year deorbit rule and the UN bodies that shape space sustainability.

Orbital Glossary

17 terms

Clear definitions of the key terms used in satellite tracking and orbital mechanics — from TLE and NORAD ID to conjunction assessment and COLA manoeuvres. Each term is explained in plain language with context for how it applies to real-world tracking and space operations.

🎓Orbital Academy — Learn these terms in context with 11 training tracks & 66 slide-deck lessons

Frequently Asked Questions

As of early 2026, approximately 14,200 active satellites orbit Earth, out of roughly 44,870 total catalogued objects tracked by space surveillance networks. The vast majority of active satellites are in low Earth orbit (LEO), with SpaceX's Starlink constellation alone accounting for about 9,850 — roughly 65% of all active spacecraft. See our full satellite count page for live data.
Space surveillance networks catalogue about 44,870 objects larger than 10 cm. ESA statistical models estimate approximately 1.2 million objects between 1–10 cm and 140 million objects between 1–10 mm. The total mass of all human-made objects in orbit exceeds 15,800 tonnes. More than 650 fragmentation events have occurred since the start of the space age. See Space Debris Statistics for the full picture.
SpaceX's Starlink is the largest by a wide margin, with approximately 9,850 active satellites as of early 2026 (out of over 11,300 launched). The next largest constellations are Eutelsat OneWeb (648 satellites at 1,200 km) and Planet Labs (~200 Earth-imaging satellites). Amazon's Project Kuiper and China's Guowang/Qianfan are deploying but are still in early stages. See our SpaceX profile and mega-constellations explainer.
The 2007 Chinese ASAT test that destroyed the Fengyun-1C weather satellite created over 3,500 trackable fragments — the most from any single event in spaceflight history. About 2,800 fragments remain in orbit as of 2026, at altitudes where they will persist for decades to centuries. The second-worst event was the 2009 accidental collision between Cosmos-2251 and Iridium 33, which produced over 2,300 fragments. See our Fengyun-1C event page.
Yes — many satellites are visible to the naked eye shortly after sunset or before sunrise, when the sky is dark but satellites are still illuminated by the Sun. The ISS is the brightest and easiest to spot. Starlink "trains" are visible for a few days after launch. See our guides: How to See the ISS, How to See Starlink, and Brightest Satellites.
The United States leads overwhelmingly with over 10,000 active satellites (dominated by Starlink). China is second with 900+, followed by the United Kingdom (~760, mostly OneWeb), Russia (~200), Japan (~200), and India (~130). See our full satellites by country ranking and individual country profiles.
Solar activity — including coronal mass ejections, solar flares and high-speed solar wind — heats and expands Earth's upper atmosphere, increasing drag on LEO satellites and lowering their orbits. Geomagnetic storms can also cause satellite surface charging, radiation damage to electronics, and GPS signal degradation. In February 2022, a geomagnetic storm destroyed 40 newly launched Starlink satellites by increasing atmospheric drag beyond recovery. See our solar storms and satellites guide for the full picture.
By total flights, Russia's Soyuz rocket family holds the all-time record with over 2,000 launches since 1966. For active rockets as of 2026, SpaceX's Falcon 9 leads by a wide margin with over 400 missions, performing the vast majority of global orbital launches. The Falcon 9 first stage has been recovered and reused over 300 times. See our Falcon 9 and Soyuz profiles for more.
Our launch schedule page shows upcoming launches from SpaceX, Rocket Lab, ULA, Arianespace, ISRO and other providers, auto-updated from Launch Library 2. With SpaceX alone launching roughly every 2–3 days, there is almost always a mission within the next 72 hours. The schedule includes live countdown timers, mission details, pad locations and webcast links.
Starlink typically delivers download speeds of 25–220 Mbps and upload speeds of 5–25 Mbps, with latency around 25–60 ms in most areas. Performance varies by region, congestion and plan tier. Competitors like Amazon's Project Kuiper (deploying 2025–2026) and OneWeb aim to offer comparable broadband. See our Starlink review and Starlink vs Kuiper comparison.
The largest space agencies by budget and capability are NASA (United States), ESA (22 European member states), CNSA (China), Roscosmos (Russia), ISRO (India) and JAXA (Japan). Other significant agencies include CNES (France), DLR (Germany), UKSA (United Kingdom) and KARI (South Korea). Together they operate thousands of satellites, multiple crewed programmes, and deep-space missions. See our space agency profiles for individual pages on each.
Rockets launch from specialised spaceports around the world. The busiest include Kennedy Space Center / Cape Canaveral (Florida), Vandenberg SFB (California), Baikonur Cosmodrome (Kazakhstan), Guiana Space Centre (French Guiana), Jiuquan and Wenchang (China), and Satish Dhawan Space Centre (India). SpaceX launches Starship from Starbase in Boca Chica, Texas. Newer sites include SaxaVord (Shetland, UK) and Esrange (Sweden). A site's latitude determines which orbits it can reach efficiently. See our 12 spaceport profiles for maps, specs and launch histories.
There is no single world space authority. The 1967 Outer Space Treaty establishes foundational principles, and the UN Committee on the Peaceful Uses of Outer Space (COPUOS) coordinates international norms. In practice, each nation regulates its own operators — the FCC and FAA in the United States, CNES in France, Ofcom and the UK Space Agency in Britain, and so on. The ITU coordinates radio frequencies and orbital slots globally. See our guides on who regulates space and the Outer Space Treaty.
A satellite is any object that orbits another body in space. In everyday usage it refers to human-made spacecraft placed in orbit around Earth for communications, navigation, weather monitoring, Earth observation, scientific research or military surveillance. Satellites range from CubeSats smaller than a shoebox to the International Space Station, which spans 109 metres. As of 2026, over 14,200 active satellites orbit Earth. See our What Is a Satellite? guide for the full picture.
The International Space Station travels at approximately 28,000 km/h (17,500 mph), completing one full orbit of Earth every 90 minutes. At that speed, the crew sees 16 sunrises and sunsets every day. The ISS orbits at roughly 400–420 km (250–260 miles) above the surface. See our live ISS tracker to follow it in real time.
Starlink is a satellite internet constellation built and operated by SpaceX. It consists of approximately 9,850 active satellites in low Earth orbit as of early 2026 — by far the largest constellation ever deployed, accounting for roughly 65% of all active spacecraft. Starlink provides broadband internet to users in 70+ countries with typical speeds of 25–220 Mbps and latency of 25–60 ms. See our Starlink review and live Starlink tracker.
The number of people in space varies as crews rotate between the International Space Station and China's Tiangong space station. Typically 6–10 crew members are aboard the ISS and 3–6 aboard Tiangong at any given time, plus occasional commercial or tourism missions. Over 680 people from 45+ countries have been to space since Yuri Gagarin's first flight in 1961. See our astronaut directory for the complete list.
When satellites reach end of life, operators are expected to either deorbit them (lowering the orbit so they burn up in the atmosphere) or move them to a graveyard orbit above the operational belt. Satellites below about 600 km will naturally re-enter within 25 years due to atmospheric drag. The FCC now requires US-licensed satellites to deorbit within 5 years of end of mission. Satellites that fail before disposal become space debris. See our guides on orbital decay, graveyard orbits and re-entry.
Kessler Syndrome is a theoretical scenario in which the density of objects in low Earth orbit becomes high enough that collisions generate debris faster than it can deorbit, triggering a cascade that could render certain altitudes unusable. The concept was proposed by NASA scientist Donald Kessler in 1978. With over 44,000 tracked objects and millions of smaller fragments already in orbit, collision risk management is a growing priority. See our Kessler Syndrome explainer for the full analysis.
The ISS orbits at approximately 400–420 km (250–260 miles) above Earth's surface, in the upper region of low Earth orbit. Its altitude gradually decreases over time due to atmospheric drag, and the station is periodically reboosted using thrusters on visiting spacecraft. At this altitude, it completes one orbit every 90 minutes at roughly 28,000 km/h. See our ISS profile and live tracker.
The global space economy reached an estimated $626 billion in 2025 and is projected to exceed $1 trillion by 2034. Satellite services (communications, navigation, Earth observation) account for the largest segment. Launch services, ground equipment, government budgets and emerging sectors like debris removal all contribute. See our full space economy breakdown for market data, investment flows and growth projections.
Launch costs vary enormously depending on the rocket and orbit. SpaceX's Falcon 9 charges roughly $2,700 per kilogram to low Earth orbit — down from over $54,000/kg on the Space Shuttle. Rideshare missions on small launchers like Electron cost around $7,000–10,000/kg. Starship aims to reduce costs below $100/kg at full reusability. See our launch cost trends page for the full history.
The Kp index is a 0–9 scale measuring global geomagnetic activity caused by solar wind and coronal mass ejections. A Kp of 0–1 is quiet, 4 is moderate, and 7+ is a severe geomagnetic storm that can affect satellites, GPS accuracy and power grids while producing visible auroras at lower latitudes. See our Kp Index Explained guide for what each level means.
Active debris removal (ADR) refers to missions designed to physically capture and deorbit defunct satellites or large debris objects. JAXA's ADRAS-J and ESA's ClearSpace-1 are the first funded missions to demonstrate in-orbit capture. The emerging ADR market could be worth hundreds of millions of dollars annually as space agencies mandate cleanup of legacy debris. See our ADR guide and debris removal market analysis.
There are roughly 30 active orbital launch sites worldwide, with more under development. The busiest include Cape Canaveral/KSC (Florida), Vandenberg (California), Baikonur (Kazakhstan), Kourou (French Guiana), and Jiuquan/Wenchang (China). New sites in the UK (SaxaVord), Sweden (Esrange) and several US states are expanding global launch access. See our 12 spaceport profiles for maps, coordinates and launch histories.
Over 680 people from 45+ countries have travelled to space since Yuri Gagarin's first flight on 12 April 1961. The number is growing rapidly with commercial crew missions from SpaceX and Blue Origin. Typically 10–15 people are in orbit at any given time across the ISS and China's Tiangong station. See our astronaut directory for the complete list.
The James Webb Space Telescope (JWST) is the most powerful space telescope ever built, launched in December 2021. It orbits the Sun at the L2 Lagrange point, 1.5 million km from Earth, with a 6.5-metre gold-coated mirror that observes in infrared. JWST has already transformed our understanding of exoplanets, early galaxies and star formation. See our JWST profile for key specs and discoveries.
Yes — dozens of nations operate military and intelligence satellites for imaging, signals intelligence (SIGINT), missile warning, secure communications and navigation. The United States, Russia, China, India, France and the UK all have significant military space programmes. Military satellites are typically classified and tracked by space surveillance networks but not catalogued publicly. See our military satellites guide.
The 1967 Outer Space Treaty is the foundational international agreement governing activities in space. It prohibits placing nuclear weapons in orbit, bans national sovereignty claims over celestial bodies, and makes states liable for damage caused by their space objects. Over 110 countries are parties to the treaty. See our Outer Space Treaty explainer for the full breakdown.
LEO (Low Earth Orbit) is roughly 160–2,000 km altitude — home to the ISS, Starlink and most Earth observation satellites. MEO (Medium Earth Orbit) spans 2,000–35,786 km and hosts navigation constellations like GPS and Galileo. GEO (Geostationary Orbit) is a circular orbit at exactly 35,786 km where satellites match Earth's rotation and appear stationary — ideal for weather and communications. See our Types of Orbits guide and glossary.
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