From an article in today's NYT about the first Israeli to fly aboard the space shuttle:

The delays gave Colonel Ramon more time to personalize his journey into space. While other Jews have gone on space flights, he is the first to request an all-kosher menu. (NASA found a supplier, and all the food in his sealed meal packs is kosher.)
Colonel Ramon describes himself as a secular Jew, but he said that in space he would try to observe Shabbat, the Jewish Sabbath, if it did not interfere with his duties. Shabbat, observed every seventh day, normally goes from sundown Friday to sundown Saturday. This raised the question of when the day of observance occurred in orbit, since the shuttle circles Earth every 90 minutes. The astronaut consulted a group of rabbis, who developed a consensus that the day of rest should be observed based on times at his launching point, Cape Canaveral.
Before becoming an astronaut, Col. Ramon was part of the group of Israeli pilots who destroyed the Osirak nuclear reactor in Iraq, thus preventing Saddam Hussein from obtaining nuclear weapons.