A large balloon reflector, capable of launching and support itself at high altitudes, with a feed system capable of steering the beam quickly enough to perform target tracking of fast-moving terrestrial, stratospheric, or orbiting objects. The large balloon reflector antenna forms a suborbital antenna system that is suitable for operation from radio to infrared wavelengths and can be used, for example, for remote sensing of objects on the ground, in the atmosphere, or in space.

A balloon reflector antenna for a satellite, including a spherical balloon with a surface transparent to electromagnetic waves and a reflective surface opposite the transparent surface. The balloon reflector antenna may further include a feed system extending from the center of the balloon that receives electromagnetic waves reflected off the reflective surface and/or outputs electromagnetic waves that are reflected off the reflective surface.

Methods and apparatus are disclosed for passively steering an antenna disposed on a balloon in a balloon network. An example balloon involves: (a) an antenna and (b) a pressure-sensitive mechanism in mechanical communication with the antenna such that a change in the balloon's altitude causes at least an element of the antenna to rotate upward or downward, a separation distance between two or more radiating elements to increase or decrease, or a separation distance between the two or more radiating elements and a reflector to increase or decrease.

A support apparatus for an inflatable communications antenna system includes a case the size of airline carry-on luggage that is dimensioned to store a deflated antenna and its accompanying power, control and inflation systems.