This was on Saturday mornings around 11, I think, circa 1995-97.
This show is NOT Hypernauts, but looks similar. There were more kids in the show, five I think, but they did have gray and different colored uniforms like Hypernauts did. No mechs. They traveled on a space ship together. I don’t why or what their mission was.
There’s only one episode I remember. At the beginning of this episode they are on some sort of port planet where they are looking at the street vendors. I think the city floating they are is either in the sky or floats ala Cloud City. One of the girl crew members is looking at a necklace for sale, but decides that she can’t afford it. The guy crew member she was with secretly trades (his harmonica?) for the necklace and gives it to her as a gift.
The rest of the episode is about these creatures that fly through the atmosphere of the planet and kind of resemble whales. They are being hunted down and harvested for this gas/chemical inside them that powers their ships (they used a similar idea for an episode of Star Wars Rebels a few years ago). The kids compare them to whales and talk about how Earth used to treat whales the way these creatures are being treated, i.e. as dumb animals. They talk about how Earth eventually realized that whales were intelligent and started treating them as equals. One kid even says something about “yeah, my dad (or uncle) had a whale lawyer once.”
The kids spend the rest of the episode trying to find a way to get these people of this planet/region to stop poaching the creatures. Eventually they find out the gas/chemical inside them is actually produced by surface vents in the planet and that the people there can harvest it from the planet surface directly. This saves the creatures from extinction and it ends on a happy note.