1st appearance on Black Jack: Son of Hariti
Astro is Iwao, son of a very beautiful, sweet and healthy woman. He goes to infant school.

As you can see, robot or human, Alvin is always after Astro. This time he's scaring him because there's a band of child kidnappers hangin' 'round the city.

Iwao's mom (Zephirus?) is a sweet and gentle lady. Every night she reads Astroboy's adventures to her beloved child. Iwao thinks that if he was Astroboy he would defeat those pesky criminals (NOTE: I'm following the spanish translation of BJ, Ed. Glénat)
Iwao is kidnapped for XXXXXX reasons (well, read the story an you'll see for yourselves. I'm not spoiling nothing now that i know BJ is been published in the USA this year). Skunk takes their leader to him, but they don't know that Shibugaki (Alvin) has given a penknife to Iwao in order to defend himself if the real kidnappers take him. And...

Alley-hoop! The leader is stabbed in the arm by the agile Iwao. He keeps on fighting until he's rescued by the police. Darn, Astro looks even more brave as Iwao than as his usual self!
2nd appearance on Black Jack: You're guilty!
If you have the vol.22 on the Dark Horse edition of Astroboy, then you've have read this one. For others, here hare some details. Astro (his name's here is unknown) plays the part of the brother of a young businessman. He's now an older version of himself. For the uniform, I guess he's about 13 or 14 here, starting secondary school.
Astro's bro is stabbed by a violent thief (very à la GTA now than I think of it). Astro seeks revenge and prepares a bait for Atlas, in order to kill him with penknife (again), but after some fast thinking, he decides is better to frame him in order to convict him in a quite memorable scene:

3rd Appearance on B.J.: Astro in an Abbey Road fashion

Uran in BJ: Money! Money! Money!
Uran had her moment of glory on BJ in this chapter. Tenma is a doctor who wants to be the medical chief of the Kanto region. Uran, called Kasumi in this story is her lovoely daughter. She wants her papa to stay with her. She loves him madly, and doesn't mind her dad being a big boss: she just wants him to be her father! Tenma, blinded by his own ambition, gets really mad at her. so mad that in the last panel makes a blooper: "GO HOME, URAN! OOPS! I MEANT KASUMI!" (in the following page, he turns into a rooster)

So, Kasumi is now alone again (naturally)
"I promised myself to treat myself
And visit a nearby tower,
And climbing to the top,
Will throw myself off"
But somebody must tell her that it's only a song, and that its author is well alive and planning an important tour for the summer (this is real info: it's the 40th-anniversary-of-his-debut tour, so if you like Gilbert O'Sullivan, buy your tickets now), because she "throws herself off" from his dad's penthouse.

And so, it's up to Black Jack to save her
SPOILER:


Cobalt on BJ: poor lil' guy... And poor Melmo!!! (thanks, Jeffbert!) BTW, why is Uran looking so pissed off there?

Atlas as a child
A cute lil' version of Atlas appears as the son of two star system characters (I don't remember the names). His father is a deceased alcoholic doctor (accident: falls downstairs) who owned BJ some money. His mother (Riiko) is a young, gorgeous and now widowed nurse who will fall deeply in love with BJ. As you can see for his posters, he's an Astro fan like all of us. The other photooo... Well, let's leave this character alone: Gaki Deka. A great manga, but not to be discussed now.

Atlas appeared as an adult in a couple of stories more.
That's it at the moment. Tomorrow I'll post Astro's cameo on Midnight.