The parachute sail with hydrostatic beam: a new concept for solar sailing

Solar sail spacecrafts are very large, lightly loaded structures which must be deployed in space. The limiting structural factor is usually the elastic stability of a number of elements subject to compressive loads. An alternative structural layout is here suggested: an inflatable beam, which is kept pressurized also after deployment, relieves all compressive stresses, allowing a very simple configuration and a straightforward deployment procedure. The layout here proposed can be used for many types of sail, from tiny demonstration vehicles to large planetary sailers, provided that their trajectory does not get too close to the Sun, and for other large space structures. Its simplicity and low cost could allow to experiment with this type of spacecraft in a near future.