The SS United States, an ocean liner bigger than the Titanic that once carried celebrities across the Atlantic at record speeds, may one day sail again.

Crystal Cruises luxury travel company announced plans Thursday to overhaul the ship at a cost of at least $700 million. The massive steamship has been docked in Philadelphia for two decades, gutted and rusting at an unused wharf on the Delaware River.

But before it can be turned into a state-of-the-art commercial vessel, the SS United States must undergo a nine-month feasibility study.

In its glory days in the 1950s, the ship carried everyone from royalty to immigrants across the Atlantic Ocean, accompanied by three on-board orchestras. At the time, it was the biggest and fastest ocean liner that had ever been built in the United States — at 990 feet, 108 feet longer than the Titanic.

On its maiden voyage in 1952, the liner's 268,000-horsepower engines propelled it across the Atlantic in three days, 10 hours, 42 minutes. That record stood until 1990. The ship was decommissioned in 1969.

The SS United States is now owned by a conservation group, with a purchase option signed by Crystal Cruises.

This is not the first time plans have been in the works for refurbishment. In 2003, the Norwegian Cruise Lines said it planned an overhaul that did not materialize.

In 2014, the conservancy said it was chasing redevelopment options that could bring the ship back to its home port of New York as a stationary, mixed-use attraction likely featuring retail, restaurants, offices and/or hotel space.

But as negotiations continued for competing sites in Brooklyn and Manhattan, the ship was racking up unsustainable costs Philadelphia, where the conservancy spends $60,000 monthly to maintain the vessel on the Delaware River, where it sits amid working piers and looms over a strip of big box stores.

Preservationists feared running out of money before a ship-saving deal was reached and had retained a scrap-metal broker. Last fall, they received a lifeline — $600,000 in donations — to keep it afloat while discussions continued.