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Speeds come out in metres and kilometres per second and km/h, distances in metres and kilometres, and periods in seconds, minutes, hours and days. Everything is computed in SI and is instant and private. Ideal for aerospace and satellite tools, space-mission and education apps, astronomy and KSP-style games, and physics calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. 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