Astro is a canine character on the Hanna-Barbera cartoon, The Jetsons. He was designed by Iwao Takamoto, and originally voiced by Don Messick.
Astro, despite being clumsy and dim-witted, was very loyal (to a fault) to the Jetsons. He was more advanced than present-day dogs, in that he had a rudimentary grasp of the English language, albeit with r's in many places they shouldn't be, or replacing other letters.
For example, "I love you, George" would be "I ruv roo, Reorge". Astro was found by Elroy in the fourth Jetsons episode, "The Coming of Astro". When Jane, Judy, and Elroy proposed keeping him to George, he was against it claiming that an Apartment is no place for a dog.
However, when trying to escape, The Cat Burglar put the mask on George. Electronimo then proceeded to chase after George. It was Astro who was trying to run from The Cat Burglar that inevitably caught the criminal by accident by crashing into him. This prompted George to decide that Electronimo was not the way to go. They gave Electronimo to the police and kept Astro as part of their family.
In the fifteenth episode, "Millionaire Astro", Astro is discovered to be Tralfaz, the long lost dog of zillionaire J.P. Gottrockets and The Jetsons have to do the right thing and return Astro to his rightful owner. In the end Mr. Gottrockets realizes how unhappy Astro is and allows him to go back home with The Jetsons. Astro hated the name and always repeated it as "Tralfaz...Yuck," or in Astro-speak: "Ralfaz....Ruck!"
Astro also appeared as the main star in Astro and the Space Mutts, a segment of Space Stars.
Astro's signature expression was "Ruh-roh!" (or "Ruh-roh, Reorge!"), supposedly the canine variant of "Uh-oh!" (expression of dismay). Scooby Doo, who was also designed by Iwao Takamoto and voiced by Don Messick, had a similar signature expression: "Ruh-Roh, Raggy!" (Uh, Oh, Shaggy!)
A running joke (literally) at the end of each episode in the 1960s run shows George Jetson walking Astro on an automatic dogwalker outside his apartment. Astro chases a cat causing the dogwalker to go fast; George loses hold of the dog leash; Astro and the cat jump to one side and both watch George forced to run for his life on the out of control dogwalker screaming for Jane to "stop this CRAZY THING!".
George eventually falls and is carried by the treadmill's belt around its path, under the machine and back up again, while Astro and the cat look on in amusement.