Question: When one goes on a trip or the like and a group of ten men gather to pray Mincha or Arvit, can they all be included in the Minyan (quorum of ten men) although they are not in an enclosed room?
Answer: When people go on trips or vacations, especially during this time of year, one must be extremely careful not to miss any prayer, G-d-forbid, and certainly not to miss donning Tefillin with the proper mindset and concentration. One must likewise make sure to recite Birkat Hamazon slowly and pleasantly. The same applies to any of the Mitzvot, for the purpose of a G-d-fearing individual taking a vacation is in order to relax his spirit and rejuvenate his strength so that he may be able to continue serving Hashem with enthusiasm, either while learning or working. Certainly, if one slacks off in matters of spirituality while on vacation, not only does this not benefit his soul at all, on the contrary, one is actually causing himself to falter by weakening himself and distancing himself from the service of Hashem. Who knows how many months or years it will take one to correct this failure?
If ten men are praying in one area, although it is certainly better for them to pray in a synagogue, it is nevertheless permissible for them to pray in an open area when there is no other choice and they are all indeed included in the Minyan. Although there are Acharonim who write that they must all band closely together and not stand far apart from each other, as long as they all hear the Chazzan and can see one another they are all included in the Minyan.
The great Rishon Le’Zion, Hagaon Rabbeinu Yitzchak Yosef Shlit”a points out though that care should be taken that none of the ten men prays in a totally separate domain, for instance, if they are praying on the sidewalk and there is a fence or gate between the street and the sidewalk, the fence acts as a partition between the domain the Chazzan is standing in and the domain on the other side of the fence (if it is at least 80 cm high). In such a situation, there is room to say that not all of the men present are included in the Minyan.
One must likewise be careful that when such a Minyan gathers that the men should not stand on opposite sides of the street or a path because the street is considered a public domain and serves to separate between the various worshippers. In this way as well, there is room to say that not all of the men are included in the Minyan.
