IST takes the view that any space station that does not have rotational artificial gravity of about 1g and radiation shielding that lowers all radiation levels to less than background levels experienced on Earth - is not fit for human habitation. Also, to avoid problems due to Coriolis forces when moving around in the space station, it must have a rotation speed of at most 2 rotations per minute, which equates to a radius of about 225 meters.
Using both an airship launched multiple suborbital rendezvous pipeline to space for dumb mass raw materials and lighter items, and a ground launched staged high suborbital rendezvous system for heavier items, IST aims to profitably build and operate high quality rotating space stations. As well as easily achieving the physical parameters for long term safety, there will be no shortage of commodities such as water and fresh food which will be increasingly produced in space as opposed to being imported from Earth.
Living in space for humans is not inherently difficult in many respects. If energy is seen as the most important resource of all, then living in space is significantly easier than living on the Earth's surface. The main problem is the availability of materials, and the technology to use them in space. Having solved the former problem, and with the latter problem being addressed by rapid improvements in fields such as additive manufacturing technology, IST has set itself the ambitious goal of a phase 1 target for space station development that will construct two 300 meter radius space stations in LEO. One will be focused on technical projects such as power station construction and maintenance, the other will be primarily for space tourism. There will also be a number of depot stations for various resources which will keep station at a safe distance from each inhabited space station.
Such space stations can support 300 persons in safety and comfort. They will orbit somewhat higher than previous generation space stations at about 800 km altitude, to reduce the requirements for orbit adjustment manoeuvres due to atmospheric drag and gravity gradients. It is also likely that as the space economy develops, LEO below 800km will become quite busy with many craft travelling to and from the Earth and various hangar and service depots. At 800km the rotating stations will orbit serenely above this activity whilst remaining easily reachable from Earth and well below the Van Allen radiation belts which begin at about 1000 km altitude.
As in all IST ventures, the safety of all persons involved will be the number one priority. Therefore all IST space stations will include enough escape pods to evacuate everyone on board up to the maximum number of persons allowed. These escape pods will feature simple life support and control systems which should be able to keep 4 persons alive for about 1 week if necessary. Unfortunately due to weight limits in the first designs of rotating space stations, these pods will not be capable of independent reentry and landing. They will however include small thruster units which should allow for orbit stabilisation even in the event of a space station malfunction which compromises the orbital stability of the space station itself.
The escape pods will only be used in the event of an extreme emergency that prevents space station evacuation by normal exit through airlocks to transfer craft. Once in the escape pods, personnel will stabilise their orbit and make for alternative accommodation in the form of other main space stations if reachable, or emergency inflatable space stations which can be launched both from the compromised space station itself or from other support stations and depots. These emergency stations may not be rotating stations and may not have the same levels of shielding as the main stations, but will be adequate to provide life support for evacuees for weeks if necessary.
It is expected that even in the event of a major malfunction, all evacuated personnel will be transferred in a matter of hours either to other main rotating space stations or returned safely to Earth.