Space requirements are difficult to ascertain. Consider the need for seed harvest, storage of seeds and veggies harvested, etc. One source that I remember stated the general rule of thumb is approx. 100 sq. feet per person. This does not take seed harvesting into consideration, but it does account for excess veggies that will be stored. I think one would be hard pressed to meet the caloric requirements of an active (self-sufficient and survival oriented) lifestyle on a mere 10 by 10 plot of ground. Of course this would depend on the veggies grown (most varieties of beets for example are 100% edible - greens and all!).
Personally, I have about 400 square feet of plantable space now and I feed a family of 3 (two adults, one child). I harvested an excess of green beans, potatoes, and carrots last year (we ate what we could while fresh and canned the rest) and still have more than half of what we harvested last year in storage. This year I am allowing the green beans to seed out and planted fewer carrots and potatoes. I also grow corn though we usually run out by Christmas. I never get enough peas for more than two meals. I give away cucumbers, carrots, lettuce, and a few tomatoes to the neighbors (just don't have the space to store them or they won't keep very long).
Climate plays a large role in yields. This year was not kind to my corn so I will likely run out before Christmas (it was too wet during germination and too hot soon after). A climate controlled environment would not only eliminate that variable, but also allow year-round production. A 100 square foot climate controlled space planted with the right combination of veggies might yield enough to feed a person year-round. This takes into consideration the need to replant each veggy before the last planting is completely harvested! If you have the space (which we won't since we'll have to provide the lighting) make your garden as large as you can handle!
Offered by Roger.