Kazue Tagami voiced Astro in episodes 97-106 while Mari Shimizu was on maternity leave.
Uran was first voiced by Yoko Mizugaki, then by Reiko Mutou, then by Kazuko Yoshikawa.
Higeoyaji was first voiced by Masaaki Yajima, then by Ayao Wada.
Tawashi was first voiced by Shingo Kanemoto, then by Kouichi Chiba.
[adult swim] aired the show as late-night filler, though only 52 episodes were aired. Curiously, it was showcased on the April Fools Day 2012 Toonami broadcast along with Trigun, despite both shows not having aired on Toonami before.
1980 TV series
Hey, It's That Voice!: Mari Shimizu reprised her role as Astro. Hisashi Katsuta also reprised his role of Ochanomizu.