Lines of fighter jets, with slender missiles under their wings, sit ready for action on a rocky desert landscape.
In the late afternoon, teams of technicians arrive to prepare the planes for night patrols over southern Iraq's no-fly-zone. As the sun disappears , F-15 and F-16 fighter jets power their engines. The earth shakes and the dusk light fills with shimmering fumes as aircraft taxi to the runway, lifting off sharply - a security technique to avoid potential terrorist attacks by surface-to-air missiles. Waiting in the skies around southern Iraq, a one-hour flight away, are hulking refuelers, guided by AWACS planes with their clumsy-looking radar discs on top.
More than a decade after the end of the Gulf War, when this base was the staging ground for US forces, it may again play a key role in a US assault on Iraq. Since the Gulf War, the US has spent millions of dollars to create one of the most highly developed military command centers in the world. The base was also used to direct the air campaign in Afghanistan.
Although Saudi Arabian officials have publicly refused permission for the base to be used to strike Saddam Hussein's regime, recent reports have quoted anonymous Pentagon officials saying they have private assurances from the Saudis that US aircraft refuelers and cargo and surveillance planes could operate from the kingdom in the event of war with Iraq. Authorization to coordinate an air campaign from Prince Sultan may also be given.
"I don't think the final answers are all in," says Brig. Gen. Dale Waters, commander of the US Air Force's 363rd Air Expeditionary Wing stationed at the base.
Such uncertainty reflects Saudi government fears that using the base to support an attack on Iraq would create internal instability and further offend the conservative religious establishment, which objects to the US military on Muslim holy land.
The Pentagon has prepared an alternative air command center at Al Udeid Air Base in Qatar. Yet this facility pales next to the capabilities of the Saudi base. Prince Sultan's key attraction is the Combined Air Operations Center that tracks aircraft in the region and processes satellite imagery and reconnaissance data from surveillance planes.
"This is a hugely capable air wing," says General Waters. "We have some of the best aircraft in the world and certainly some of the best trained crews in the world. So it's put here as a combat wing with all that capability for a reason."
The base is also valued for its security infrastructure.
Most of the base, built on 230 square miles of desert, is empty, barring patches of dry scrub and palm trees. The location makes it easy to spot potential threats.
The operations center, known as Ops Town, lies well inside the main gate - manned by Saudi security personnel - and behind a second tier of US security. A sign at the entrance to Ops Town reads: One Team. One Fight.
Many US forces were transferred to Prince Sultan following a terrorist attack on a military housing complex at Dhahran in 1996 that killed 19 service men. "We are near the top installation for security anywhere in the world," Waters says.
The young pilots who fly the $30 million fighter aircraft stationed here have recently faced more frequent attempts by Iraqi forces to shoot them down during their daily no-fly-zone patrols. "People think the mission in Iraq is combat free, but it's not," says Waters, who flies patrol missions at least once a week using his call sign "Muddy." "Our aircraft are engaged by Iraqi ground fire almost every day."
No warplanes have been shot down by Iraq - Waters says Iraq's air defenses are "beat down" - but unmanned Predator spy planes have been lost.
Some 4,500 US airmen live and work on the base, nicknamed Al's Garage - a wordplay on the nearby town of Al Kharj. In summer, temperatures soar to 130 degrees F., and winter nights can plunge close to freezing. Airmen sleep in simple dorms and dine in mess halls named Camel Lot and Mirage.
Security concerns mean that few ever leave the base during their 90-day tours. Time off is spent watching movies on a big screen inside a canvas clam shell, exercising in a state-of-the-art gym, or by the pool. A library and Internet access are also available.
Jeffrey Hunt, ranked airman 1st class, is a crew chief on F-16s, responsible for getting the plane into the air and home again. He is two weeks into his tour, after which he'll return to his job at the Air Force base in Misawa, Japan. "[In Japan] we were just launching and recovering jets out training," he says. "But every day we launch our jet, and they've got live [missiles] on, and we know they are doing pretty serious missions out there. You have a different mind-set.
"I'd like to be here [if war breaks out in Iraq]," he says. "I'm ready to go now if I have to. It's what we've trained for. I look forward to the chance."