FALLS CHURCH, Va. (AP) — In an effort to save dwindling space, the Army is proposing new rules to limit who can be buried at Arlington National Cemetery. Under the current rules, the cemetery would run out of space by the mid-2050s, the Army says. The proposed restrictions would preserve the cemetery's lifespan for another 150 years. "Arlington National Cemetery is a national shrine for all Americans, but especially those who have served our great nation," Acting Secretary of the Army Ryan McCarthy said in a statement. "We must ensure it can honor those we have lost for many years to come." Under the proposals, veterans who retired from active duty and were eligible for retirement pay would no longer be automatically eligible for in-ground burial. They would be eligible, though, for above-ground "inurnment" of cremated remains. Those who were killed in action or received awards such as the Purple Heart or Silver Star could still receive an in-ground burial. U.S. presidents and vice presidents also would retain eligibility. The proposed rules will now be subjected to the federal rulemaking process and published in the Federal Register, which allows the public to submit comments. If the public comments prompt no revisions, the new rules could take effect in about nine months. The cemetery, which is managed by the Army, has already conducted extensive public outreach to collect feedback on how it should shepherd its existing space. More than 250,000 people responded to a survey by the cemetery, and officials say roughly three-quarters of respondents favored restricting eligibility for burial in some way to preserve the cemetery's lifespan. The cemetery's founding dates to the Civil War, when Union soldiers commandeered the estate of Confederate Gen. Robert E. Lee overlooking the Potomac River and the nation's capital to bury the war dead. More than 400,000 people are buried in the cemetery, and only 95,000 burial spaces remain, though a planned expansion will add 37 acres (15 hectares) of burial space and more than 10 years of life to the cemetery under the existing rules. Even with the expansion, though, the cemetery faces a severe capacity problem in coming decades. Under the current rules, nearly all of the 22 million living armed forces members and veterans are eligible for burial at Arlington, the Army said. The proposed new rules restrict in-ground burial to those killed in action, award recipients of the Silver Star and higher who also served in combat, Purple Heart recipients, former prisoners of war, presidents and vice presidents of the U.S., and those who died in combat-related service deaths while conducting uniquely military activities. Exceptions can also be made for veterans with combat service who "also served out of uniform as a government official and made significant contributions to the nation's security at the highest levels of public service." Eligibility for those opting to be cremated is broader.