Space launch

Liftoff is of two main types: rocket launch (the current conventional method), and non-rocket spacelaunch (where other forms of propulsion are employed, including airbreathing jet engines).

The boundary represents the midpoint of a gradual transition over tens of kilometers from the relatively gentle winds of the Earth's atmosphere to the more violent flows of charged particles in space, which can reach speeds well over 268 m/s (880 ft/s).

In the past fifty years, spaceflight has usually meant remaining in space for a period of time, rather than going up and immediately falling back to earth.

At lower altitudes, due to the high speed required to remain in orbit, air friction is an important consideration affecting satellites, much more than in the popular image of space.

Apart from catastrophic failure of the launch vehicle itself, other safety hazards include depressurisation, and the Van Allen radiation belts which preclude orbits which spend long periods within them.

If a trajectory optimization problem can be solved at a rate given by the inverse of the Lipschitz constant, then it can be used iteratively to generate a closed-loop solution in the sense of Caratheodory.

Beside ecological environments, lands and their communities, particularly indigenous peoples, have been colonized to build the necessary infrastructure, disregarding them without reaching out for consultation or consent.

A SpaceX Falcon Heavy rocket for instance burns through 400 metric tons of kerosene and emits more carbon dioxide in a few minutes than an average car would in more than two centuries.

Airdrag is a significant issue with essentially all proposed and current launch systems, although usually less so than the difficulty of obtaining enough kinetic energy to simply reach orbit.

Non-rocket spacelaunch refers to theoretical concepts for launch into space where much of the speed and altitude needed to achieve orbit is provided by a propulsion technique that is not subject to the limits of the rocket equation.

Due to the exponential nature of the rocket equation, providing even a small amount of the velocity to LEO by other means has the potential of greatly reducing the cost of getting to orbit.