U.K.-based Reaction Engines’ Skylon plane is designed to take a 12-ton payload  of cargo and passengers into space from a conventional airport and return them back down to the same runway.

The concept for the Skylon is based on a synergistic air-breathing rocket engine (SABRE) that uses jet propulsion to reach the edge of the Earth’s atmosphere before switching to rocket power to get into orbit.

Skylon is thought to cost about $10m per flight once development costs have been paid. A trip to orbit in an upright seat, for stays of up to 14 days, would cost around $500,000.