Uran

Astro's robot sister with a shown adoration towards Astro; she is a superhuman robot with a naive, tomboyish personality. Constructed by Dr. Ochanomizu as a "gift" for Astro, Uran is an extremely mischievous little girl who constantly lands her older brother in trouble. While lacking Astro's weaponry and propulsion systems, she is extremely powerful (50,000 horsepower) and regularly accompanies him on various missions (or attempts to). Like Astro, she is fully capable of experiencing human emotions - though being somewhat less 'mature'. In the 2003 anime, Uran has the ability to communicate with animals. Her name is based on uranium, a metal used to power nuclear reactors.