Scientists are planning to build a space camera the size of a football field to spot distant planets.
The New Worlds Imager would work in the same way as a simple camera made from a box with a pinhole in one end - except the "pinhole" would be 30ft wide.
Light entering the hole would form an image on photo film at the end of the box. The hole blocks out scattered light, making the image sharper.
The idea was one of 12 selected for funding by US space agency Nasa.