Located just a stones throw from the main station in Miyazaki City is the Miyazaki Science Center, easily visible by the rocket standing in front. I stopped in befoe heading down the coast on the 22nd day of my walk around Kyushu.
It is very much aimed at kids and is very colorful and noisy and somewhat resembled a games cnter.
The first floor is primarily about space and Japoan's space program which is based a little further south in Kagoshima.
There is also a planetarium and lots of interactive exhibits. There is virtually no information in English but kids would be sure to enjoy it.