Since the first satellite was launched from earth in 1957, Don Fritz has wanted to go into space. The 41-year-old Oxon Hill High School science teacher used to search the night skies with binoculars, when he was a child, for man-made orbiting objects. Like thousands of other Americans, and several of his current students, he dreamed of reaching the stars.

Yesterday, as it was announced that two of his students' experiments will ride in the belly of a space shuttle flight set for 1985, Fritz was beaming in a front-row seat at the Goddard Space Flight Center in Greenbelt. At last, he had found himself in space--almost.

"I'd walk to Florida tomorrow if I could get on the shuttle," said Fritz, one of two advisers working on space shuttle experiments with students at Oxon Hill. "I feel this is as close as I'll ever get--it's a terrific experience."

Fritz's thrill was mirrored in about 100 school administrators, students, teachers and parents at yesterday's press conference. Eight experiments from six county high schools were selected by a team of judges that included local scientists and NASA engineers as well as county school officials.

A local aerospace company, Orbital Systems Inc., donated space aboard the shuttle for student experiments last year.

"It's like a dream come true," Robert Shockley, special assistant to school Superintendent Edward J. Feeney, told students yesterday.

From the beginning of the space shuttle program, NASA has made a limited amount of space available to any public takers for between $3,000 and $10,000 for about five cubic feet of space. Of the 78 spaces reserved on past and future shuttles, 15 have gone to high school groups. Only one high school, from Camden, N.J., has been represented on a shuttle to date, according to NASA's Len Arnowitz.

That school sent a colony of carpenter ants into space, but none of the ants survived, prompting a major scientific inquiry.

Marcia Williams, a junior from Oxon Hill High, was not concerned that her experiment, on the behavior of a liquid in space, might also flop.

"There is still the recognition that you have achieved something positive," said Williams.

Half the Prince George's experiments will test the reactions of tiny living things to the zero gravity and cosmic radiation of space. One experiment, designed by students from Friendly High School, may provide a clue to digestive problems sometimes reported by astronauts in space.

The Friendly experiment will send a colony of Escherichia coli, bacteria normally present in human intestines that aid digestion, into the weight-free space environment. In addition to other changes the experimenters will be looking to see if zero gravity produces any mutations in E-coli.

Vilecia Summers, 17, said it was possible that such mutations could make E-Coli unable to survive in the intestines.

"It's interesting being on the threshold of something new, especially if it will lead to other experiments NASA can do," said Summers. "It's sort of like being a pioneer."