AstronautiCalc

AstronautiCalc is a scientific calculator built for people who work with orbits. Enter an altitude or radius and it computes the orbital parameters that follow: period, semi-major axis, circular and escape velocity, revolutions per day, maximum eclipse duration, apparent Earth angular radius and range to horizon. ORBITAL DYNAMICS J2 nodal precession rate, and the inclination that makes an orbit sun-synchronous. GROUND STATION VISIBILITY Maximum time in view and slant range, tabulated at 0, 5, 10, 15 and 20 degrees elevation, so you can size a pass without reaching for a spreadsheet. DELTA-V Plane change per degree, and the burn required to lower perigee for de-orbit. IT SHOWS ITS WORKING Key quantities carry a help entry giving the formula behind them and stating the assumptions made, including the circular-orbit simplification. SCIENTIFIC CALCULATOR A full scientific keypad with trigonometric, hyperbolic and logarithmic functions, factorials, powers and roots, memory registers, degrees or radians, and base conversion between decimal, binary, octal and hexadecimal. PHYSICAL CONSTANTS ON THE KEYPAD The astronomical unit, speed of light, Earth radius and gravitational parameter, solar constant, Planck and Boltzmann constants, elementary charge, Avogadro's number, Stefan-Boltzmann constant, standard gravity, the solar year, the gas constant and J2 — each one keystroke away. UNIT AND TIME CONVERSIONS Convert angle, solid angle, area, volume, length, mass, force, energy, power, pressure, temperature, time and moment of inertia. Convert between UTC, local time, TAI, GPS, POSIX, Julian Date, Modified Julian Date, Excel serial dates and day-of-year, with leap seconds accounted for, and jump straight to the J2000, GPS, POSIX and Excel epochs. Every value can be copied out and pasted between the calculator, the conversions and the astrodynamics sheets. No accounts, no adverts, no tracking, no network access of any kind. IMPORTANT This application provides engineering calculations intended for preliminary analysis and educational use. Results have not been independently verified or validated for mission-critical or flight use. Users are solely responsible for verifying all outputs against authoritative sources and for determining suitability for any specific application. The full disclaimer is available in the app under Help & Disclaimer.