Bristol Spaceplanes Limited (BSP), based in Bristol, was formed in 1991 to realise low-cost access to space by exploiting the then thirty years of spaceplane design experience of its founder, David Ashford. Ashford worked on the European Aerospace Transporter (spaceplane) studies in the early 1960s with the Hawker Siddeley Aviation Advanced Projects Group. BSP has developed plans for Spacecab, an update of the European Aerospace Transporter project of the 1960s. Spacecab is designed to carry six astronauts to a space station or launch a 750 kg satellite.

As a lead-in to Spacecab, the company has plans for the Ascender sub-orbital spaceplane. Ascender would carry one paying participant and one crew member. It would take off from an ordinary airfield and climb to 26,000 feet (8 kilometres) at subsonic speed, before starting the rocket engine. It would then accelerate to a speed of around Mach 3 on a near-vertical climb and then follow an unpowered trajectory to reach a height of 330,000 feet (100 kilometres).

In 1993, BSP received a contract from ESA for a feasibility study of the Spacecab orbital spaceplane. This showed that new technology was not required and that the development cost of an operational prototype was about two billion dollars. In 2003, BSP received a grant from the UK Department of Trade and Industry to help fund a feasibility study of the then latest version of the Ascender sub-orbital Spaceplane.