Also, some astronauts have died from accidents over the years.
There have been several astronauts who have died in accidents over the decades.
この場合、次のような言い方ができます。
ーAlso, some astronauts have died from accidents over the years.
「また、長年に渡り何名かの宇宙飛行士が事故で亡くなった」
some astronauts で「何名かの宇宙飛行士」
ーThere have been several astronauts who have died in accidents over the decades.
「この何十年かで、事故で亡くなった宇宙飛行士が何名かいる」
several astronauts を使っても表現できます。
ご参考まで！
カナダ 
