LIKE SO MANY Hallmark Hall of Fame presentations, there are moments in "A Smile as Big as the Moon" that seem too sweet, too pat, too orchestrated. But also in typical fashion, Sunday's offering is a compelling tale that generates enough real moments and emotion to sweep past a few missteps.

It's the story of a special- education teacher in Michigan who decides one day that he's had enough of the limits the world puts on his students. Why can't they have a shot at going to Space Camp, like every other student in the country?

With John Corbett ("Sex and the City") playing teacher Mike Kersjes and an interesting group of young actors playing the students, it's a story that negotiates a predictable path. But it's based on a true story, and the efforts of the students are very inspiring. So you will need that box of tissues Hallmark presentations typically require by the time the credits roll.

The real challenge here is portraying the students, who are coping with everything from Down syndrome to autism to dyslexia, in a way that's both honest and moves the story along.

It helps the show's credibility that several of the young actors have the same challenges as the students they're portraying.

As the story slowly unfolds, Kersjes is struck with the thought of how inspiring the weeklong Space Camp at the U.S. Space & Rocket Center in Huntsville, Ala., would be for his students.

One-Ben (Peter ten Brink), a boy with Down syndrome with dreams of becoming an astronaut--would especially benefit.

The first reactions to the teacher's space camp dream are telling. The students could never handle the discipline, preparation, physical and academic demands, say both his own principal and the officials at Space Camp.

Kersjes, who is fed up with the limitations people place on his students before they even get the chance to try, keeps pushing.

He uses friends, emotional blackmail and political connections to slowly but surely give his students a shot.

There's another big hurdle, too. Kersjes has to figure out how he would come up with the camp fees if the students did get accepted.