About nine
o'clock
And only an occasional flash of the emergency light to check the compass was necessary to keep them moving in the right direction . There was n't much talk . There was n't much to talk about . About nine o'clock the boys stopped and opened one of the containers of food and ate a quick meal of sandwiches . This was followed by a carefully measured ounce of water , and fifteen minutes later they resumed their march across the New Sahara . About ten o'clock , Deimos , one of the small twin moons of Mars , swung up overhead , washing the desert with a pale cold light . By morning , when the cherry-red sun broke the line of the horizon , Tom estimated that they had walked about twenty miles .