Not only does the ion now appear from a distance as a charged particle, the missing electron causes profound changes in the way the molecule bonds or interacts with other molecules. A typical high energy particle of radiation found in the space environment is ionized itself and as it passes through material such as human tissue it disrupts the electronic clouds of the constituent molecules and leaves a path of ionization in its wake. Particles encountered in space commonly have enough energy to disrupt the nucleus of target atoms and these collisions can cause nuclear reactions which generate new and potentially more damaging particles.
Nuclear reactions make the analysis of ionizing radiation collisions much more difficult.
At energies just above the visible, ultraviolet photons are able to remove electrons from some of the most easily ionized types of molecules such as those found in and around human cells. This is true because they can either be stopped with thin shields or, as in the case of x-rays and gamma rays, their intensity is fairly low in most volumes of space where humans desire to go. Some have claimed that low frequency electromagnetic fields from power lines are responsible for increased cancer risk but this has been discredited . This leaves the highly energetic particles which can pass through shielding materials as the most obvious threat to humans in space. Typically, these particles are highly charged and very energetic.