LAKE BUENA VISTA, Florida (AP) -- A 4-year-old boy died after passing out while aboard Walt Disney World's ''Mission: Space'' attraction _ a ride that has caused previous concerns because of its intensity.

Daudi Bamuwamye passed out Monday afternoon while on the attraction, which simulates a rocket launch and trip to Mars. The Orange County Sheriff's Office said his mother carried him off the ride and employees helped her place him on a bench.

Paramedics tried to revive him, but he died about 5 p.m. at Celebration Hospital.

The sheriff's office said the boy did meet the minimum 44-inch (112 centimeters) height requirement for the ride at the Epcot theme park, which simulates twice the normal force of gravity.

A cause of death could not be immediately determined and an autopsy was expected Tuesday.

Officials said the boy was from Pennsylvania, but his hometown was not immediately available. He was on the ride with his mother and sister.

The $100 million (euro83 million) ride, one of Disney World's most popular, was closed after the death.

In 2003, Disney began placing motion sickness bags in the ride. During an eight-month period in 2003-04, six people over age 55 were taken to the hospital for chest pain and nausea after riding it, though none of them was found to have any serious injuries.

It was the most hospital visits for a single ride since Florida's major theme parks agreed in 2001 to report such problems to the state. Updated figures were not immediately available.

Signs warn visitors about the intensity of the ride.

"For safety you should be in good health, and free from high blood pressure, heart, back or neck problems, motion sickness or other conditions that can be aggravated by this adventure," one sign on view last year said.

Disney officials in a statement after the boy's death that they are "providing support to the family and are doing everything we can to help them during this difficult time.?"