The cosmic radiation field in space is rather complex in terms of composition and with respect to energy of the constituent particles. The intensity and energy spectrum of the cosmic radiation may considerably change with time as well. A three dimensional silicon detector dosimetry telescope (TRITEL), with sensitivity in 4 , has been recently developed in the Centre for Energy Research, Hungarian Academy of Sciences. The instrument comprises three mutually orthogonal, fully depleted, passivated implanted planar silicon detector pairs and it is designed to measure the energy deposit of charged particles. From the time spectra and the deposited energy spectra measured, the flux of charged particles, the absorbed dose, the linear energy transfer (LET) spectra and the average quality factor of the cosmic radiation, as well as the dose equivalent can be determined. This way the stochastic biological effects of the cosmic radiation in orbit can be characterized. Measurements have been already performed in the stratosphere on research balloons and on board the International Space Station (ISS). The orbit of RISESAT (Rapid International Scientific Experiment Satellite) gives an excellent opportunity to measure the dosimetric quantities listed above at higher altitudes and higher latitudes than at which the ISS is orbiting around the Earth. Q : quality factor Subscripts Q : defined with the quality factor T : a given organ or tissue T