Puerto Rico to get aid from the Navy's 900-foot long floating hospital, the USNS Comfort The ship called the Comfort has operated around the world.

 -- An 894 foot-long U.S. Navy floating hospital, said to have one of the largest trauma centers anywhere in the United States, is heading to Puerto Rico.

The USNS Comfort, which can hold as many as 65 civil service mariners and 1,215 Navy medical personnel, left Norfolk, Virginia, today to help bring relief to the U.S. territory devastated by Hurricane Maria.

U.S. officials estimate it will take the Comfort, which has a maximum speed of about 20 miles per hour, up to a week to sail to the island. The ship's personnel received orders Tuesday to help with disaster relief in the territory.

What is the USNS Comfort?

"USNS Comfort’s primary mission is to provide an afloat, mobile, acute surgical medical facility to the U.S. military that is flexible, capable and uniquely adaptable to support expeditionary warfare," according to a Navy fact sheet on the ship.

But its second mission is to serve as a full hospital service to support U.S. disaster relief and humanitarian operations around the world.

What is on board the Comfort?

According to the Navy, the ship has one of the largest trauma facilities anywhere in the United States.

"The hospital has a full spectrum of surgical and medical services including four X-rays, one CAT scan unit, a dental suite, an optometry and lens laboratory, a physical therapy center, a pharmacy, an invasive angiography suite and two oxygen-producing plants," the Navy said.

The ship maintains up to 5,000 units of blood at any given time for its medical services.

Where has the Comfort served?

The ship has been in service since 1987 and has gone around the world.

Its deployments have included Haiti in 2010 following a catastrophic earthquake and the Gulf of Mexico in the aftermath of hurricanes Katrina and Rita in 2005. The ship spent 12 days in Pascagoula, Mississippi, alone after the 2005 storms, providing care to nearly 1,500 people before moving off the coast of New Orleans.

The ship has also supported U.S. troops in Iraq. In the Persian Gulf in 2003, the Comfort's personnel cared for nearly 700 wounded American military service members and Iraqi civilians at the start of the U.S. operation there.

After the terrorist attacks on the U.S. on Sept. 11, 2001, the Comfort docked in Manhattan so that the crew could provide meals, housing, medical and psychological services to volunteers and relief workers at Ground Zero.