Abstract: A balloon with an internal corner reflector for radio waves is built with the reflecting plane of the reflector freely suspended from a cord frame system which is only secured in the points of suspension. The reflector is suspended inside a balloon which is composed of single flat pieces of a resilient material. Manufacture of the reflector balloon may substantially be done in one plane and the balloon primarily envelopes the reflector very tightly. The suspension utilizes the resiliency of the balloon corners. Balloons which are observed from below may have four internal corners with downwards facing openings and may also be designed to provide rotation.