Sub-orbital spaceflight

Part of a series on
Spaceflight
History History of spaceflight Space Race Timeline of spaceflight Space probes Lunar missions Mars missions
Applications Communications Earth observation Exploration Espionage Military Navigation Settlement Telescopes Tourism
Spacecraft Robotic spacecraft Satellite Space probe Cargo spacecraft Crewed spacecraft Apollo Lunar Module Space capsules Space Shuttle Space stations Spaceplanes Vostok
Space launch Spaceport Launch pad Expendable and reusable launch vehicles Escape velocity Non-rocket spacelaunch
Spaceflight types Sub-orbital Orbital Interplanetary Interstellar Intergalactic
List of space organizations Space agencies Space forces Companies
Spaceflight portal
v t e

A sub-orbital spaceflight is a spaceflight in which the spacecraft reaches outer space, but its trajectory intersects the surface of the gravitating body from which it was launched. Hence, it will not complete one orbital revolution, will not become an artificial satellite nor will it reach escape velocity.

For example, the path of an object launched from Earth that reaches the Kármán line (about 83 km [52 mi] – 100 km [62 mi]^[2] above sea level), and then falls back to Earth, is considered a sub-orbital spaceflight. Some sub-orbital flights have been undertaken to test spacecraft and launch vehicles later intended for orbital spaceflight. Other vehicles are specifically designed only for sub-orbital flight; examples include crewed vehicles, such as the X-15 and SpaceShipTwo, and uncrewed ones, such as ICBMs and sounding rockets.

Flights which attain sufficient velocity to go into low Earth orbit, and then de-orbit before completing their first full orbit, are not considered sub-orbital. Examples of this include flights of the Fractional Orbital Bombardment System.

A flight that does not reach space is still sometimes called sub-orbital, but cannot officially be classified as a "sub-orbital spaceflight". Usually a rocket is used, but some experimental sub-orbital spaceflights have also been achieved via the use of space guns.^[3]