Three weeks ago, NASA announced a new program to entice more commercial activities on the US side of the International Space Station (ISS). Starting in 2020, the station will be open to vacationers and others at a per-night-rate of $35,000.

While this is the first time the American side of the ISS has been promoted as a high-flying hotel, there have been five tourists who have visited the Russian side of the station, starting with Dennis Tito in 2001. He spent eight days in the ISS.

The hotel room was part of a complete travel package negotiated with the Russians. The total cost was $20,000,000 including round-trip accommodations on a Soyuz spacecraft. Dennis probably thought this was an expensive trip, but he could afford it.

As it turns out, he had a great deal on the hotel accommodations and the transportation. Today, Dennis would have to pay $245,000 per week for an "American room" and probably close to $60,000,000 for the round-trip transport to and from the station.

NASA has specified certain limitations on private sector station visitors. The agency will allow only two short private astronaut missions per year, with a limit on each visit of 30 days. Such visitors must also use US transportation providers such as SpaceX and Boeing. Each private visitor will have to meet medical and training requirements for spaceflight, as imposed by private commercial entities that will manage such adventures.