Imagine, for a moment, that you’re stranded on Mars.
You do have shelter, but are faced with rapidly dwindling supplies of air, water, and food. You’re just barely able to contact Earth, but he spacefaring nations of the world can’t help you—they’ll never get supplies to you in time. So you appeal to less conventional means of survival.
But at this point you’re faced with a difficult choice, because all but two of the world’s superheroes are busy. (Also, most of them have a grudge against you, which is why they don’t care when they hear about your situation.)
So: to whom do you appeal for help? Aquaman, or The Atom?
I’m pretty confident that the correct answer here must be The Atom.
The way I figure it, all you’d need to do is convince him to become really, really large. Then, assuming you could find a way to kill him, his flesh and blood would provide plenty of sustenance (conveniently preserved by the Martian environment). And, done right, you could siphon off the oxygen in his enormous lungs.
That’s Stage 1 (survival). Stage 2 (rescue) happens as a consequence, when the other supers eventually notice The Atom never came back from Mars. Once they realize what you did, they send a rescue mission. Not because they like you (they still don’t), but they hated The Atom even more. Why? His hobby was keying peoples’ cars. The jerk.
Aquaman is the wrong choice. There are no oceans on Mars.