WASHINGTON — The Base Closure and Realignment Commission will decide the fate of the Portsmouth Naval Shipyard at a public meeting on Friday.

In a letter to the seven other members of the BRAC panel released Monday, Chairman Alan Dixon urged that all commissioners not consider “last-minute appeals” involving any of the 174 affected bases beyond midnight Tuesday.

“As we go into the final days of our deliberations, I think all of us should bear in mind that, in all likelihood, our votes will decide which military installations will be closed and which will remain open,” said Dixon, a former Republican senator from Illinois.

“In a real sense, we will be acting in a judicial capacity, and our actions should be taken in an environment free of the pressures from those affected by our decisions,” he said. “As a result, I have decided that after midnight on Tuesday … I will not take any more telephone calls or have any more meetings with individuals or groups who have an interest in the outcome of our final deliberations — whether it is members of Congress, senior Defense Department officials, or community groups.”

Dixon said the cases made “over the last four months” by congressional delegations and affected community groups should have more bearing on the base closing process than “last-minute appeals based on information we may or may not have time to analyze or verify.”

Maine congressional delegation aides expressed optimism that Portsmouth will survive the pending BRAC vote.

Last week, the eight members of Congress from Maine and New Hampshire argued against closing Portsmouth during a 15-minute presentation before commission members. The same arguments were conveyed during a visit by the commissioners to the New England nuclear submarine yard earlier in the month.

Portsmouth, which is the nation’s oldest Navy shipyard and the builder of America’s first nuclear submarine, employs about 4,100 Maine and New Hampshire workers. The Navy did not put Portsmouth on its original inventory of possible base closings, but decided to add the facility to an expanded list last month.