How does a desert wanderer who lost track of Shabbat fulfill the obligation of Kiddush and Havdalah on his designated seventh day?

If a person lost track of which day is Shabbat while wandering in the desert, from which day does he begin counting his seven-day cycle?

3 opinions

May a desert wanderer who has food/provisions perform labor on any of the seven days (including days that might not be Shabbat)?

5 opinions

When labor is permitted for sustenance (after provisions are exhausted), how much may the wanderer earn — may he work extra on one day to avoid labor on subsequent days?

4 opinions

May the desert wanderer walk (travel) on any day of the week, including his designated seventh day?

4 opinions

On the designated seventh day, may the wanderer perform other rabbinic prohibitions (shevutim d'rabbanan) besides walking?

4 opinions

Is a desert wanderer who lost track of Shabbat obligated to wear tefillin on his designated seventh day?

1 opinions

Does the same 'lost Shabbat' framework apply to someone who lost track of Yom Tov (e.g., does not know if today is a chag)?

2 opinions

If a wanderer knows the number of days since he departed (e.g., today is the fourth day since he left) but not which day of the week he departed, when may he freely perform labor?

3 opinions