astro-good guys. Here are six of the best Jace, their pet monkey Blip, and his Phantom Cruiser. His power bands and inviso-belt probably didn't hurt, either. When he retired from interstellar crime-fighting, he got a sweet gig as a talk show host. Let's see Skywalker carry a show for ten years.
Green Lantern. Another member of the "outer-space superhero" subset, Green Lantern's adventures were recently turned into a big screen movie starring Ryan Reynolds, but he's been dealing with threats both foreign and domestic in comic books and on TV for decades. He has a pretty cool power ring that can make anything he imagines real, but even with power like that he manages to bump into bad guys that can challenge him.
James Bond (in "sci-fi heroes. Sure, it's generally considered the worst Bond movie (which is nonsense, there have been several worse ones), but how can that be when there are all those laser beams getting fired around? Sometimes you just have to accept the gift that you're given.
Samus Aran. The heroine of the "Metroid" series of games pretty much defines "sci-fi hero". She has an awesome power suit, a cool arm cannon, and a wicked spaceship-what more do you want? Although her occupation is technically listed as "bounty hunter", she actually spends a lot of time clearing areas of evil Space Pirates and other alien scum.
Iron Man. Not all sci-fi heroes have to travel to space. Take the metallic star of the "Iron Man" comics, TV shows, and movies. He's undoubtedly sci-fi; just look at him. But he tends to stay a little closer to the ground, unless he has to leave the atmosphere with The Avengers or something. The point is that he's always saving the day-isn't that what matters?