As the name implies, lifting bodies are shaped to generated a lift force that allows for a more gradual deceleration, lower peak heating and can even allow for manoeuvring during re-entry. Several capsules have generated a lift force by having an unequally distributed mass, such as the Apollo crew capsule for example. Their lift force is however small in comparison to the drag. This page will only cover the vehicles that could generate a lift force proportional to that of the drag.
One possible advantage of using a lifting body is that it can be used to land horizontally on a runway, making retrieval operations significantly easier. This on its turn makes space planes good candidates for a reusable vehicle.
There have been many proposals and concepts of lifting bodies, or space planes, of which only few were built and even fewer were flown to space. This page provides an overview of what types of lifting bodies have been flown. Note that this classification of lifting bodies is not universal and that there are different ways to group the designs of lifting bodies.
In the late ‘50s the US performed tests with the X-15 rocket plane to reach altitudes close to the edge of space at hypersonic velocities. The X-15’s shape is based on that of conventional aircraft, where the wings are horizontal and easily distinguished from the body. The first attempt of the USSR to develop a spaceplane was the MiG-105 as part of the Spiral program.
The Space Shuttle and Buran are two famous examples of space planes that used a winged lifting body to adjust their trajectory and land on a runway.
Some lifting bodies have no wings and only use their body shape to generate lift during re-entry. However, this eliminates the highweight associated with the wings but generally doesn’t allow for a horizontal runway landing. Instead, a conventional parachute recovery system is usually installed to recover the vehicle. The European IXV (Intermediate eXperimental Vehicle) is a clear example of a lifting body re-entry vehicle without wings. It made use of two adjustable flow deflectors to control its attitude and trajectory. Another example of a wingless lifting body is the Japanese HYFLEX spacecraft.
Some re-entry vehicles have adopted a blended wing body shape, where the wings and body form a smooth integrated shape. Missions such as the Dream Chaser, X-24, X-38 and others have used a V-shaped wing profile that benefits the vehicle’s stability and manoeuvrability in the atmosphere.
There are countless different shapes that a lifting body vehicle can have. The shape usually compromises many factors such as re-entry heating, payload capacity, aerodynamic loads, desired trajectory, crew visibility, launch vehicle interface, and many others.
For example, the ASSET vehicle had a conical shape with two small wings on the sides. It represented the nose cone of the Dyna-Soar spaceplane and was flown to investigate the aerodynamic heating effects during re-entry.