Space can be a hostile and at times unpredictable environment. Although years of testing go into developing technology that can tackle the challenges it presents, a laboratory can replicate only so much. Building instruments able to cope with the realities of space requires extensive research both on Earth and above it.
Radiation is a particular wild card. Testing the full effects of radiation on new electronic components is difficult in a laboratory which offers, by definition, a controlled environment. Space is not controlled. Space requires instruments to deal with a mix of complicated and fluctuating environmental factors – complex circumstances to simulate in an experiment.