3 . “It will be marvelous. It will be spiritual.” This is the ________ tagline that Virgin Galactic used in 2004 to attract potential customers to its planned space tourism services. It promised that, within five years, it would take a total of over 3,000 passengers on life-changing trips in its spaceships. On July 11, 2021, after a last 90-minute delay, Virgin Galactic finally began its fulfillment of that original ________. For four minutes, its six temporarily weightless passengers, including the firm’s British co-founder, Sir Richard Branson, saw the planet against the blackness of outer space.

Back on the ground, Sir Richard called the experience “magical”. He may have ________ the fact that he was able to reach space earlier than Jeff Bezos, a fellow billionaire but much wealthier. On July 20, Bezos would go slightly higher, for slightly less time, in a vehicle that had been built by his own spacefaring company, Blue Origin.

The two tycoons (大亨) are among a growing number of ________ who believe that space tourism’s time has come. Suborbital (亚轨道的) tourism is part of a broader space economy that has rapidly grown over the past decade ________ technological advances. However, it is highly ________ that this will be true.

For now, Blue Origin and Virgin Galactic will offer ________ suborbital flights to paying customers. Blue Origin is focusing much more on the development of a large new rocket that will be used for the launching of satellites, on selling advanced rocket engines to other companies, and on bidding (投标) on NASA contracts such as the recently announced plan to send humans back to the moon. ________, Bezos doesn’t see Blue Origin as a provider of services to adventure-seekers.

Even this 4-minute suborbital travels have a(n) ________, apparently. A major survey found that nearly two in five people with a net worth of over five million dollars would consider paying $250,000, Virgin Galactic’s current price, for a ticket. The business could be ________, once regular flights begin to offset (抵消) the rockets’ development costs. But how fast and by how much is ________. Without tourist-friendly destinations to visit (the capacity of the International Space Station is strictly limited), orbital tourism, with its far higher ticket prices, will not be a huge earner.

Another challenge — and the industry’s biggest remaining uncertainty — relates to ________. History has shown that a disaster, ________ in the early stages of an industry, can set progress back by years. NASA ________ its plan to send the untrained to orbit in 1986 after a school teacher was killed along with the rest of the crew in the Challenger tragedy. It was another 15 years before the next untrained person would ________ the journey on a Russian craft.