Editing Aerospike engine (section)

===Variations===
Several versions of the design exist, differentiated by their shapes. In the '''toroidal aerospike''' the spike is bowl-shaped with the exhaust exiting in a ring around the outer rim. In theory this requires an infinitely long spike for best efficiency, but a similar effect can be achieved by blowing a small amount of gas out of the center of a shorter truncated spike (like [[base bleed]] in an artillery shell).

In the '''linear aerospike''' the spike consists of a tapered wedge-shaped plate, with exhaust exiting on either side at the "thick" end. This design has the advantage of being stackable, allowing several smaller engines to be placed in a row to make one larger engine while augmenting steering performance with the use of individual engine throttle control.