The first accommodation in orbit available to the public won't be a real "hotel" - it's more likely just to be rooms in pre-fabricated cylindrical modules connected together, because this is the easiest way to start. However, it will gradually grow in quantity and quality to include more elaborate facilities constructed in orbit - eventually including full-scale hotels and even apartment blocks. Starting at $thousands per night, costs will fall continually as the volume grows, and it's likely that guests will choose to stay for longer and longer.

At some point, some people may choose to live in orbit permanently - or even retire in orbit!

Zero-G is certainly very relaxing, and may be the most comfortable place for the elderly who can afford it! Note that if you live in zero-G for months on end, your muscles and bones get weaker. This may not be a problem for people who aren't intending to come back to Earth(!) but most people would need to take counter-measures (see Heath and Fitness) An alternative is to live in a rotating hotel where there is partial gravity (see Orbital Hotel Design).

What a stay in orbit will be like will obviously depend on the type of accommodation in which you're staying. And that will depend particularly on the phase which the business has reached at that time. b

The earliest orbital accommodation could be just a few years away - remember, for a bare minimum, Russian flight-proven space stations are on sale today. (The only problem is getting there cheaply!) At first it will comprise the minimum required to attract customers, and might not even be permanently staffed, but only when a party is visiting. Early facilities will probably all be based on cylindrical modules, being simplest and cheapest to launch and assemble. Inside there'll be private guest rooms, communal rooms used as lounges and dining rooms, areas with windows for looking outside, and space for enjoying zero-gravity, with guidance from staff whose work will be an interesting cross between that of airline cabin attendants, hotel staff - and gymnasts!

These simple facilities will grow, offering "more of the same" - more guest rooms, more zero-gravity rooms, more lounges and bars, etc - and there are several reasons for believing they will grow quite quickly. First, building orbital accommodation is easier than building passenger launch vehicles. Remember, the first US space station, Skylab, was operational in 1973 (see " A House in Space") and a facility like that would be quite adequate for the early phase of "adventure tourism" in orbit.

Building orbital accommodation is also technically easier than building an orbital research station, because there's no need for most of the advanced technology in a research station - such as high temperature furnaces, super-computers, high-data-rate communications, accurate pointing at stars, etc. What we need are "normal" things that you find in a hotel, like bedrooms with windows, bathrooms, bars, lounges, zero-G playrooms, karaoke bars, viewing rooms with big windows, kitchen and dining room. Making these requires no new technology, so we can start as soon as we can get to and from orbit easily - although new technology will no doubt help to improve things in future.

Before passenger launch vehicles are certified to carry passengers to orbit like scheduled airlines, they'll need to perform hundreds of test-flights. These flights could be used to carry cargo to orbit - and since the space industry doesn't have very large cargo launch requirements (other than communications satellites), hotel modules and durable supplies such as water are obvious candidates. So passenger accommodation facilities may be ready and waiting in orbit even before true scheduled passenger flights begin!

Accommodation facilities made from modules can be expected to develop progressively because they will become more attractive to guests as they grow larger and more varied and more entertaining - like modern terrestrial "resort hotels". Thus we can expect to see more comfortable guest rooms with en-suite shower and toilet, different styles of dining rooms, a range of lounges and bars with different decor and entertainments, sports and exercise facilities, discos, and so on. We'll also see different types of specialised facilities. For example, some may specialise in sports with stadiums, pools and zero-G sports competitions. Some may be themed on popular space fictions like Star Trek or Star Wars. Others may aim at an older clientele with zero G botanical gardens and specialised astronomical viewing rooms. The possibilities are almost limitless.