A tunable radiator for space application has been developed to meet stringent requirements in terms of electrical and environmental specifications but also low mass, simple manufacturing and low cost. The element is based on the folded PIFA antenna, with size of one quarter of wavelength. It is mechanically tunable to adjust input impedance for any various positions on the satellite body and possible obstacles and protrusions. Results in terms of radiation pattern, S parameters, shock and vibration tests are presented. The antenna operates in UHF band (400 MHz) and it has been designed to act as the basic element for miniaturised multi-function antenna systems on board of small satellites that can operate in three different radiating modes.