We where driving back to our cabin in fort davis from the mcdonald observatory on highway 118 in the fort davis mountains. we came over a hill just before a turn when my girlfriends attention was grabbed by an object moving in the sky. this object looked like a white ball of light similar to the stars behind it, but this object was moving in an upward trajectory and changed its course rapidly moving back downwards before disappearing behind the mountain. at this point the object has caught my attention now that the vehicle is facing its direction. my eyes look up from the road to see a very large fiery red object with an extremely short tail in very clear detail just before it disappeared behind the mountain ahead of us. this object made no sound and did not light up the dark landscape around us in either white or red light. we each only saw one object in the same point sky disappear behind the same point behind the mountain. no other objects where in the sky besides the stars.