>Is it safe to be launch stuff like that?

As safe as any other launch. Does of course bring to mind all the yelling 
and shouting from environmental groups when the last Mars Orbiter did a 
swing by earth to get a slingshot. I believe there were demonstrations at 
Cape Canaveral at the time of the swing by.

>I mean then those space crafts include radioactive reactors
>in some possible risky way. How do they start the reactor?
>And when?

Well, I presume the reactor is "producing power" like a battery from the 
moment it is connected up.

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist