Fast forward to the future. A domed colony has been formed on Mars, where human beings live, work and go to school. But something (other than a hospitable climate) is missing. No, not oxygen. Not sunlight. Not mountains or oceans or trees.

It’s grapefruit juice.

And it’s the simple premise behind a profound message in “Maine Girl on Mars,” an original musical written by a Brewer doctor, Stephen Typaldos, that debuts at 7 p.m. Friday at the Grand Auditorium in Ellsworth.

“It’s about making a difference in the world,” Typaldos explained. “Everybody can contribute. It doesn’t have to be a big thing. If everybody does little things then we can live in a better world.”

Or, a better planet, as the case may be. In the play, the young heroine, Trudy Kooper, leaves her parents and cats on Earth to go to college on Mars. The budding scientist has a mission: to grow grapefruit trees on Mars that produce fruit big enough to yield juice. Because while humans have made Mars their home in the play, there’s nothing they miss more from their days on Earth than their morning glass of grapefruit juice. Her mom and cats are sad that Trudy’s so far away, but her father is excited that his daughter is living her dream.

“It’s about following your calling – to follow your dreams, to go where fate takes you,” Typaldos said. There are only so many opportunities in life to do what you need to do. Don’t let them slip through your fingers.”

The idea for the play came more than 10 years ago, when Typaldos invented a story to tell his young daughters, now 12, 14 and 17. His oldest daughter, Brooke, has a lead role in “Maine Girl on Mars” as Aries, the Mars Kitten-Cat.

“I wanted to have a story that I could tell them that would be appropriate – about people making a difference in the world,” Typaldos said. “Some of the songs go back even further than that, though. ‘Here I Am’ was a song I sang to my daughter Brooke when she was a baby and now she sings it back to me.”

Trudy Kooper’s character was based on Brooke, but because Brooke has limited acting experience, Typaldos and the coordinating director Marge Kasten held auditions for the role. When the fresh-faced Marty Kelley walked in, they knew they had found their Trudy.

“She was just what we thought Trudy should look like,” Kasten said.

Kelley returned to Maine five years ago after living in Boston, where she gained acting experience on stage and in the feature film “Fallen Angels.” She also has appeared in several Penobscot Theatre Company productions. When she saw Typaldos’ script, and heard the play’s pre-production soundtrack, with Brooke on vocals, it was a great fit.

“I was committed to doing it,” she said. “When I heard his music, I was totally amazed. It was just so beautiful.”

Typaldos wanted Trudy, who inherited her father’s tendency to dream and her mother’s pragmatism, to be a role model for adolescent girls. And he wanted the play to be a wholesome production that would appeal to the whole family. He worked in subtle humor and emotion for the adults, while the cute characters and singing appeal to the kids.

“One of the major points of the play is to offer children in Maine the opportunity to see something that’s worth seeing, something that’s not bogged down with negatives,” Typaldos said. “There’s nothing negative about ‘Maine Girl on Mars.’ ”

There are no bad guys, no sticky situations, no conflict. Just a girl, a grapefruit tree, and a dream. And like his heroine, Typaldos gets to live his dream, too.

“It’s a dream come true,” Kasten said. “It was Dr. T’s dream. He wrote it, but to actually bring it to the stage, to bring it to the Grand, that’s a really big deal. This is an original musical. There aren’t too many of those.”

“Maine Girl on Mars” will be staged at 7 p.m. Friday, Aug. 23, and Saturday, Aug. 24, and at 2 p.m. Sunday, Aug. 25, at the Grand Auditorium in Ellsworth. Tickets cost $12 for adults, $6 for children 16 and under, and are available at the box office or by calling 667-9500.