Last Friday, July 20th, was the 43rd anniversary of mankind's first extraterrestrial visit to another heavenly body. The moon. Apollo 11 was the result of decades of work by tens of thousands of researchers, scientists and engineers all over the world. The program was supported by the leaders of 72 countries. This event was probably mankind's single-most magnificent technological feat.

Neil Armstrong and Buzz Aldrin were the two astronauts on the moon, but they represented all of humanity and its quest to explore the unknown. Many important space events followed the Apollo Program, including 135 flights to low earth orbit on the first reusable launch system, the Space Shuttle.

We are now experiencing the birth of space tourism, beginning with short suborbital flights and leading all the way to hotels in space, and beyond. For a deposit of $20,000 you can now book a flight on Virgin Galactic's SpaceShipTwo in which tourists will experience several minutes of "zero G" in the vacuum of space.

There is no denying it, commercial space tourism is about to blossom into a huge industry. The laws of supply and demand tell us that increased demand leads to competition, and competition leads to lower prices and better products. It is not too far a stretch to conclude that the cost of space access for everyone will decrease significantly over the coming years.

On the other side of the coin is the fact that, although space is BIG, low earth orbits will become even more congested than they are today. Orbiting hotel operators will want their guests to have a breathtaking view of the blue planet, and reusable launch vehicle operators will want to keep the altitude low to minimize ascent and reentry energy needs.

Thus, hotel altitudes will likely be at or near 400 km. In fact, this part of near-earth space could become very congested, with the many orbiting hotels and daily flights to and from low earth orbit. Traffic controls will surely be introduced by the FAA. In addition to the current Air Traffic Control system, we can look forward to a Space Traffic Control system. Such things are already being studied.

Eventually, there will surely be dozens of orbiting hotels. Every major chain will want to have one in orbit. For example, think of the Hilton hotel in the film: "2001: A Space Odyssey." Add to this the large number of rocket skis that every hotel guest will want to rent for a day.

On any given day sometime in the future there may be hundreds of manned orbiting objects at 400 km, all maneuvering in three dimensions and all travelling at 7.7 km/sec. Add to this the fact that all decaying orbital debris above 400 km passes through 400 km on the way to reentry.

Compared this with traffic on the Chesapeake Bay on a summer weekend. There are usually hundreds of sailboats all maneuvering at about 6 knots. A quick calculation tells us that the orbiting hotels and rocket skis will be travelling some 2,500 times faster than a sailboat. Obviously, an effective space traffic control system is going to be a real challenge.

When Neil Armstrong took that first step on the moon at 4:18 EDT on July 20, 1969, he was surely thinking about the historic importance of the event. However, it is doubtful he contemplated the day when the skies would be filled with space tourists. Nevertheless, history tells us that man must explore, and that man must continue the quest for EXTREME vacations.