Ionising radiation is emitted all the time by sources. what one word completes the sentence?

Radioactive substances give out radiation all of the time. There are three types of nuclear radiation: alpha, beta and gamma. Alpha is the least penetrating, while gamma is the most penetrating. Nonetheless, all three are ionising radiation: they can knock electrons out of atoms and form charged particles.

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )