This right here is the real problem I had with the space pen. I used to use them religiously until I was losing one every couple months.

The ones without the clips are the worst, because they'll roll off of anything. They also had a nasty habit of falling out of my pockets when I sat down/got up. They are excellent pens though.

It seems to have lead a charmed life. I lost several of the ones that had no clips, they just rolled away unseen over the years.