AUGUSTA — The Maine Charter Commission unanimously voted to give conditional approval to the proposal to open the Baxter Academy School of Science in Portland for September 2013, a year later that proponents had originally proposed.

The board said it wants to see a revised application containing recently submitted information by Sept. 30 and to conclude detailed negotiations for the charter contract no later Jan. 30.

Proponents of Baxter Academy had planned to open the school this September, but the commission two weeks ago delayed approving the plan because it had questions about its budget.

Meeting with the commission this morning, John Jaques, who heads the nonprofit group behind Baxter Academy, said the group wouldn’t have enough time to open the school this September.

“We didn’t feel it was in the students’ best interests to try to open the school with approval not in place in mid-July,” he said.

In a separate vote, the commission voted 5-1 to approve the plan for a charter school in Cornville for 2012.

Proponents say they expect the school will open prior to Oct. 1. The commission two weeks ago had voted not approve the plan, but the proponents convinced the board to reconsider after it submitted a revised budget that showed a $25,000 surplus after the close of the first school year. The school will have at least 45 students.

The commission is charged with authorizing as many as 10 charter schools over the next 10 years. The commission began reviewing applications in May with the hope of approving some for the upcoming school year.

A charter school is a public school that receives public funding but is created and operated by parents, teachers and community leaders, and is largely exempt from the rules and regulations of the area’s school district.

Supporters say charters fit niche students and can offer a tailored curriculum that public schools can’t. Opponents say that many charter schools fail because of faulty business plans, and that they can hurt public schools by siphoning students and public funding.

Commission members two weeks ago expressed several concerns about Baxter Academies, including whether renovations to a building it would use, at 54 York St. in Portland, would carry into the school year.

A bigger concern, members said, is whether Baxter Academies is financially stable.

Jaques said the school has a $500,000 line of credit to help with startup costs.

“We are on rock solid financial footing starting off because of this line of credit.”