A. predicts      B. operation     C. employ      D. limited      E. maj

     We're waiting to take trips to outer space. When will it happen? According to individuals in the growing field of space tourism, it may be in five or fifty years.

     Space Adventures is taking ____55____ for the flights, similar to the first manned spaceflights. The trip will cost $ 90,000, with a $ 6,000 deposit required.  More than 200 people have made reservations, said Sarah, Dalton, the company spokeswoman.

     John Spencer of the Space Tourism Society says that a more realistic ____56____ for regular space travel is 50 years. Issues of expense, difficulty, and danger must still be resolved. Oh yes --- a reusable vehicle must ____57____ be invented.  He adds, however, that ten years from now, a ____58____ number of people may be able to visit a space station. He says he expects a fleet of private space vehicles or “space yachts (快艇)” to be in ____59____ in 20 to 25 years. They will do what he calls “orbital super yachting.” After that, there will be cruise lines, like those that travel the Earth's oceans, as well as space hotels and resorts.

     There have been only a few studies to determine the public's interest in space tourism, but they all conclude that a ____60____ of people would like to visit space and would be willing to pay good money for it.

     According to expert Patrick Collins, between 5 million and 20 million people will head for space by 2030. He also ____61____ 100 flights a day leaving Earth. It would be ____62____ to have more than 100 hotels in Earth's orbit, a few more orbiting the moon, and a few on the moon's surface. These hotels would ____63____ more than 100,000 people, who would work month-long shifts. Each hotel would have a service station. Such service stations would provide oxygen, water, and hydrogen. They might also ship environmentally safe electric power back to Earth. If all the issues can be resolved, Collins says that space tourism could one day become a $1 trillion industry.