👨‍🚀 Space Glossary

Human Spaceflight

The systems, operations, and milestones of crewed space missions — from life support and EVAs to docking, crew vehicles, space stations, and the boundary of space itself. 8 terms, each explained in plain language with key data and links to live trackers.

EVA EVA Any activity performed by an astronaut outside a spacecraft — a spacewalk 270+ (as of 2026)6–7 hours KL Kármán Line The internationally recognised boundary of space at 100 km altitude 100 km (62 miles)80 km (50 miles) M Microgravity The near-weightless condition experienced in orbit — not zero gravity 10⁻⁶ g RE Re-entry The passage of a spacecraft through Earth's atmosphere upon return from space 7.8 km/s (28,000 km/h)1,600–2,700°C SS Space Station A habitable spacecraft in orbit designed for long-duration crew stays ~420 tonnes~400–420 km, 51.6° ST Space Tourism Civilian spaceflight for recreation, adventure, or personal experience ~$250,000–$450,000$50–$100+ million S Splashdown Landing a returning spacecraft in the ocean ~25 km/h at impactLand landing T Tiangong China's permanently crewed orbital outpost 3 modules, T-shaped~390 km · 41.5°

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All terms 🌐 Orbit Types 📐 Orbital Elements 📡 Tracking & Space Surveillance 🚀 Manoeuvres & Propulsion 🛡️ Debris & Space Safety 🛰️ Spacecraft Systems 🏗️ Launch & Ascent ☀️ Space Environment ⚖️ Policy & Regulation 📍 Navigation & Timing 🔭 Earth Observation 📡 Amateur Radio & Satellites 🔭 Deep Space & Astrophysics 🌐 Satellite Internet & Mega-Constellations 🪐 Planetary Science & Exploration