Melba Moore is happy about the part she plays on television this week. Hers is the starring role in "Charlotte Forten's Mission: Experiment in Freedom," an American Playhouse production on PBS.

"It's airing during Black History Month," said Moore, "and Charlotte Forten's an unsung hero . . . The role was right up my alley -- she was a school teacher from Philadelphia who goes to South Carolina as a missionary. My first profession was as an educator. All I had to do was be myself."

Melba Moore was happy too about the previous role she played on television. She was featured on the "Ellis Island" miniseries.

"Just as 'Hair' and 'Purlie' came along and were beautiful accidents, 'Ellis Island' came along and I thought, 'Fabulous -- I get to play the part I live, an actor trying to expand her career.' It also put me with Richard Burton and Faye Dunaway and on mainstream, prime-time television. That was high- quality exposure and a stepping stone to credibility as an actress . . . I think I was more valuable to (the producers of 'Forten') as a result of 'Ellis Island.'>"

Forten was a member of a prominent, free black family and an active abolitionist. Her place in history began to take shape in 1861 when Union forces secured the Sea Islands off the Georgia coast near the South Carolina border. Plantation owners fled, leaving their slaves -- about 80 percent of the island's population -- to enjoy -- and cope with -- early emancipation. The islands became an experiment in black transition from slavery to freedom. Forten, then 21, ventured south to help with the undertaking, and kept a diary on which this Playhouse production is based.

The film was shot on location Beaufort, S.C. The area, with its heat and humidity, aggravated what Forten thought of as "lung fever." "Charlotte Forten had pleurisy and TB," said Moore, "and that was a swampy area. Anyone with a (respiratory) difficulty cannot take that environment."

The climate got to Moore, too. "At first I thought I was really getting into the part," she said. Later, she realized that asthma, which she'd outgrown as a teen-ager, was coming back to haunt her. "When I played Charlotte during her period of illness," she said, "I wasn't faking."

Moore, who was born 39 years ago in New York City, started out somewhat the same way Forten did. "I taught music in the Newark public schools," she said. "I seemed to have special gifts for it. But I had this gnawing to get into show business . . . I felt I was swallowing my dream."

"Hair" and "Purlie," which won her a Tony for best supporting actress in a musical, were early successes for her. "When I did 'Purlie,' which put me on the map, I had no idea where I was going," she said. "Being a musical it allowed me to go to music." Eventually she was exposed to all parts of show business, "and I never said no to any of them."

The next door that may open for her is a TV series. She says she's been working on one for CBS for two years. While it's been brewing, "The Cosby Show" has shot to the top of the Nielsen ratings for NBC, creating a bullish market for funny series featuring blacks.

Originally, said Moore, the concept of her show had her playing a lawyer. But Cosby's wife is a lawyer. "So the role's been changed to have me working in a mayor's office for tourism," she said, "giving me a chance to meet all kinds of people." The show would be filmed in New York, keeping her close to her home, husband and 7-year-old daughter.

And, said Moore, "my character will have a white female friend."

A white female friend? Psst. Have you seen "Sara"?