Differences between revisions 23 and 25 (spanning 2 versions)
 ⇤ ← Revision 23 as of 2021-07-16 19:05:55 → Size: 1909 Editor: KeithLofstrom Comment: ← Revision 25 as of 2021-07-17 06:22:25 → ⇥ Size: 2575 Editor: KeithLofstrom Comment: Deletions are marked like this. Additions are marked like this. Line 5: Line 5: Not just the initial 0.11 MJ/kg from the Earth's rotation, but also because the vehicle "pushes against" the 80 km rotor/stator Not just the initial 0.11 MJ/kg from the Earth's rotation, but also because the vehicle "pushes against" the 80 km rotor/stator track. Line 18: Line 18: The launch loop track curves from slightly inclined (below orbital velocity) to mostly horizontal at higher speeds, to escape velocity and higher. Momentum is transmitted to the track and rotor, slightly displacing the track backwards and slowing the rotor; positions and velocities are soon restored by cable tension and surface motors, so the long term net energy change to the system is negligable.Hence, we can approximate total launch energy: $Launch_Energy ~=~ Vehicle_Drive_Energy ~+~ Motor.Losses ~+~ Atmospheric.Drag.Energy$ $Motor_Losses$ include resistive losses in conductors, and hysteresis losses in the magnetics. $MoreLater Line 19: Line 27: # E < μ/r Climbing out of the Earth's gravity well requires energy, but a launch loop on the rotating Earth can launch to infinity with less than the classical μ/r gravitational escape energy. The rest of the escape energy is taken from the rotational energy of the Earth itself. Not just the initial 0.11 MJ/kg from the Earth's rotation, but also because the vehicle "pushes against" the 80 km rotor/stator track.  \large G 6.67408e-11 m³/kg/s² Gravitational constant \large M 5.972e+24 kg Mass of Earth \large \mu = G M 398600 km³/s² Standard gravitational parameter of Earth \large R 6378 km Equatorial radius of Earth \large T 6458 km Equatorial radius of launch track day 86400 s solar day (relative to sun) sday 86141.1 s sidereal day (relative to fixed stars) \large\omega = 2\pi/sday 7.29216e-05 radians/s Earth sidereal rotation rate \large v_e 465.09 m/s Equatorial surface rotation velocity \large v_t 470.09 m/s 80 km track rotation velocity The launch loop track curves from slightly inclined (below orbital velocity) to mostly horizontal at higher speeds, to escape velocity and higher. Momentum is transmitted to the track and rotor, slightly displacing the track backwards and slowing the rotor; positions and velocities are soon restored by cable tension and surface motors, so the long term net energy change to the system is negligable. Hence, we can approximate total launch energy: • Launch_Energy ~=~ Vehicle_Drive_Energy ~+~ Motor.Losses ~+~ Atmospheric.Drag.Energy Motor_Losses include resistive losses in conductors, and hysteresis losses in the magnetics.$ MoreLater

and surface radius \large R . The standard gravitational parameter \large \mu for the planet is the product of the gravitational constant \large G and \large M : \large \mu ~=~ G M . The gravity at the surface of the planet is \large g(R) ~=~ \mu / R^2 , and the gravity at radius \large r above the surface is \large g(r) ~=~ \mu / r^2 .

For an

E<μ÷r (last edited 2021-07-17 07:19:46 by KeithLofstrom)