Since angular momentum is conserved, then \(L_{p}=L_{a}\); if the orbit parameters \(a\) and \(e\) are known and the velocity at either the apogee or perigee point is known, then the velocity at the o...Since angular momentum is conserved, then \(L_{p}=L_{a}\); if the orbit parameters \(a\) and \(e\) are known and the velocity at either the apogee or perigee point is known, then the velocity at the other point is known: One can change the spacecraft velocity at perigee to create a circular orbit whose radius is equal to the perigee distance, or one can change the spacecraft velocity at apogee to create a circular orbit whose radius is equal to the apogee distance.
This page discusses Tycho Brahe's precise astronomical measurements and his assistant Johannes Kepler's subsequent development of his own laws of planetary motion, as Brahe's data did not support the ...This page discusses Tycho Brahe's precise astronomical measurements and his assistant Johannes Kepler's subsequent development of his own laws of planetary motion, as Brahe's data did not support the Heliocentric model. Kepler's First Law describes elliptical orbits of planets around the Sun. His Second Law states that planets cover equal areas in equal times, moving faster when nearer to the Sun.
