We are presenting preliminary results of the development of the Technology Demonstrator of the photon counting laser altimeter for planetary studies. This device is expected to be a universal instrument applicable in various space missions. The device should provide altimetry and surface radiometry in the range of 400 to 1400 km with one meter range resolution under rough conditions - Sun illumination, space radiation, etc. The Technology Demonstrator is the modular test equipment dedicated to test individual critical components, concepts and technologies: the laser source, the photon counting detector and its electronics. The concept and techniques to be investigated are: the energy budget of the altimeter, range resolution, the signal to noise ratio under various background light conditions, photon counting data acquisition, signal mining and processing techniques.