I think (based on you saying 'space colony or spaceship' and 'one kid remembering Earth' and also the UV sunlamp) that you actually watched "All Summer in a Day" by Ray Bradbury.
"All Summer in a Day" is a science fiction short story by Ray Bradbury, first published in the March 1954 issue of The Magazine of Fantasy & Science Fiction.
And the plot synopsis from there:
The story is about a class of students on Venus, which, in this story, is a world of constant rainstorms, where the Sun is visible for only one hour every seven years.
One of the children, Margot, moved to Venus from Earth five years earlier, and she is the only one in her class to remember sunshine, since the Sun shone regularly on Earth. She describes the Sun as "a penny", or "like a fire in the stove", and relays in a poem to the class that "I think the sun is a flower/That blooms for just one hour". The other children, being too young ever to have seen it themselves, do not believe her. The other students, in particular a boy named William, bully and ostracize her, and just before the sun comes out, William rallies the other children and they lock her in a closet down a tunnel.
As the Sun is about to appear, their teacher arrives to take the class outside to enjoy their two hours of sunshine and, in their astonishment and joy, they all forget about Margot. They run, play, skip, jump, and prance about, savoring every second of their newly found freedoms. "Oh, it's better than the sunlamps, isn't it?" one of them cries.
Suddenly, a girl catches a raindrop in her hands. Thunder sounds, then the lightning comes, and the children run back inside as the sun disappears and it starts to pour again. At this point, one of them remembers Margot, who is still locked in the closet. Ashamed, they let her out of the closet, standing frozen, embarrassed over what they have done and unable to "meet each other's glances."
The precious Sun has come and gone, and because of their despicable act, Margot, who loved the Sun the most, has missed it.
Wikipedia also mentions it was adapted into a 30 minute show for TV:
A 30-minute television adaptation, originally broadcast on the PBS' children's series WonderWorks in 1982. The ending is expanded to show the children atoning for their horrible act by giving Margot flowers that they picked while the Sun was out.