Think about that for a moment. While we have lived here on Earth as a species for millions of years, we now inhabit a realm beyond, solely because of our ingenuity and will. At any given time, there are up to 6 astronauts/cosmonauts on board, living and working above us every day, months at a time, every year, for the last 13 years (it was unmanned during its initial construction phase).
While NASA's space shuttle fleet and Russian Soyuz spacecraft used to be the primary means of resupplying the station and transferring crew, with the shuttle's retirement, this task has fallen entirely on Russia. However, resupplying the ISS can also be accomplished with automated cargo haulers of which there is a growing number of makes and models. There is the venerable Russian Progress freighter, JAXA's H-II Transfer Vehicle, the ESA's Automated Transfer Vehicle, and the newest, Orbital Sciences' Cygnus spacecraft.
There is also the impressive SpaceX's Dragon capsule which has already delivered cargo to the ISS and is currently being developed to transport crew in the near future.
Why is the ISS Important?
Together, the ISS and the growing fleet of spacecraft servicing it, represent the development of the tools we need to permanently inhabit space. While the planet's surface is of finite dimensions, in orbit and beyond, there is infinite space to expand -- a very suitable environment for humanity's infinite needs and desires. Solving the challenges of living permanently in orbit allows us to build bigger and better space stations and eventually, permanent, heavily populated space habitats.
|The final goal are immense orbital habitats constructed from asteroids and advanced fabrication techniques spun on an axis to provide centripetal force (artificial gravity) and lined with both human structures and features of both our natural ecosystems on Earth, or engineered ecosystems optimized for life in such an environment.|
Looking at space stations that came before the ISS, like Russia's Mir, we can see how much progress we have made, and how much of the ISS' progress is owed to the work done on stations like Mir. Future stations will likewise be indebted to the research, technology, and workflows being developed on the ISS.
While the ISS may have other functions and roles, its role as a portal to permanently settling space is perhaps its most important. It is a stepping stone toward being able to build worlds beyond Earth, lined with both environments suitable for humans and to preserve and propagate our natural ecosystems.
You can see the ISS' current position in orbit using the ISS Tracker here, and there is the NASA ISS mission page as well as streaming ISS video feed here.
Here are some more thoughts on why colonizing space is so important...