Relatives of Ilan Ramon, the Israeli astronaut on the space shuttle Columbia, cannot follow the routine mourning process under Jewish law because of the way he died.
Jews must bury their dead within 24 hours, then immediately begin observing a ritual called sitting shiva - seven days during which mourners are expected to stay at home, greet visitors and pray.
It is unclear whether any of Ramon's remains will be found, which means his family must consult with a rabbi about how to proceed.
Practices vary among branches of Judaism and rabbis have some discretion in individual cases. The same problem was confronted after Sept. 11, when few full bodies were recovered in the World Trade Center rubble.
Jewish law requires direct evidence to confirm a death, normally the body itself. In Ramon's case, the disintegration of the shuttle should be evidence enough to allow the family to hold a memorial service and begin sitting shiva immediately, said Rabbi Kassel Abelson, chairman of the Committee on Jewish Law and Standards for the Conservative movement.
If some body parts are found later, the family will be directed to bury the remains and sit shiva until sundown of that day, he said.