What is the composition of callisto?

What moon phase has more than half the moon illuminated? What two processes practiced by scientists increase the likelihood of a successful outcome in science? Do winds and a hurricane make a tornado? Distance north or south on a map can be measured by which of these? What date did Valentina Tereshkova get to space? How tall do you need to be an astronaut? How did alpha centauri get its name? Why don't hot air balloons take flight in hot humid weather? What if you send a bottle rocket 15 kilometers in the atmosphere which layer would it be in? Why does the sun seem so close? What time did miners get up in the morning? How many days have passed since 6th January 1968? What would you pack for a picnic on the moon? What did they use hot air balloons for in the 1700-1899? Why can't a balloon rise and leaves earth's atmosphere? How would life be without stars? How many Doctor Whos have their been Doctor Who? What storm is measured with a fujita scale? Who was the fifth person to go into space? Why is there no oxygen on Mars?