An autopsy on a 4-year-old boy who died after passing out on a Walt Disney World spaceship ride found no trauma, and more tests will be conducted to determine a cause of death, officials said.

　　Daudi Bamuwamye of Sellersville, Pa., passed out Monday on the "Mission: Space" ride, which simulates a rocket launch and trip to Mars. The attraction is so intense that it has motion sickness bags and several riders have been treated for chest pain.

　　During the ride, Daudi's mother, Agnes, noticed that his body was rigid and that his legs were stretched straight out, but she thought he was just frightened, according to a sheriff's report.

　　When the ride ended, the victim was limp and unresponsive, and he could not be revived. An autopsy Tuesday showed no trauma so further tests will be conducted. A cause of death may not be known for several weeks, said Sheri Blanton, a spokeswoman for the medical examiner in Orlando.

　　"Now it's going to be a matter of, 'If it wasn't trauma, what did it?'" Blanton said.

　　The ride was closed after the death but reopened Tuesday after Disney World engineers concluded that it was operating normally. No changes were made to the ride or to rules regulating who can ride it.

　　"We believe the ride is safe in its current configuration," Disney spokeswoman Jacquee Polak said. The sheriff's office said the boy met the ride's minimum 44-inch height limit.

　　More than 8.6 million visitors have gone on "Mission: Space" since it opened in 2003, Polak said.

　　Elsewhere, another heavily promoted, scary theme park ride was shut down last week. The Kingda Ka roller coaster at Six Flags Great Adventure in Jackson, N.J., billed as the world's fastest when it opened to the public last month, was closed June 8 after it malfunctioned during a test when no one was aboard.

　　On Tuesday, park officials determined that a piece of liner covering an area under the coaster's tracks had dislodged and "damaged a number of other parts," spokeswoman Kristin Siebeneicher told the Asbury Park (N.J.) Press.

　　Siebeneicher said the park is trying to identify the problem to make sure it does not recur.