What is xeylene?

Why does an astronaut wear a special type of suit? How many planets does the universe have? What is the synonym of awe? What is a moon probe? Who built the first hot air balloon? Is Saturn v the same as Saturn 5? What are clouds called that have a flat bottom? Why is NASA exploring mars? If a guy said he wants space but still calls you does he still want you back? How do you join NASA? When did Buzz Aldrin graduate from collage? Where is delphinus located in the sky? Are there any sounds in space, or is it completely silent? What is the Roman name of Zeus's wife? On what date does the sun appear directly over the equator? In what year was the mercury thermometer invented? Do aliens live on a planet in another solar system? The space shuttle orbits Earth at approximately 8000 M per S. The shuttle stays in orbit because the? What are the three major divisions layers of the moons interior? Which planet does not have only one moon?