<P> Anousheh Ansari became the first Iranian in space and the first self - funded woman to fly to the station . Officials reported that her education and experience make her much more than a tourist, and her performance in training had been "excellent ." Ansari herself dismisses the idea that she is a tourist . She did Russian and European studies involving medicine and microbiology during her 10 - day stay . The documentary Space Tourists follows her journey to the station, where she fulfilled "an age - old dream of man: to leave our planet as a "normal person" and travel into outer space ." </P> <P> In 2008, spaceflight participant Richard Garriott placed a geocache aboard the ISS during his flight . This is currently the only non-terrestrial geocache in existence . At the same time, the Immortality Drive, an electronic record of eight digitised human DNA sequences, was placed aboard the ISS . </P> <P> The ISS is maintained in a nearly circular orbit with a minimum mean altitude of 330 km (205 mi) and a maximum of 410 km (255 mi), in the centre of the thermosphere, at an inclination of 51.6 degrees to Earth's equator, necessary to ensure that Russian Soyuz and Progress spacecraft launched from the Baikonur Cosmodrome may be safely launched to reach the station . Spent rocket stages must be dropped into uninhabited areas and this limits the directions rockets can be launched from the spaceport . It travels at an average speed of 27,724 kilometres per hour (17,227 mph), and completes 15.54 orbits per day (93 minutes per orbit). The station's altitude was allowed to fall around the time of each NASA shuttle mission . Orbital boost burns would generally be delayed until after the shuttle's departure . This allowed shuttle payloads to be lifted with the station's engines during the routine firings, rather than have the shuttle lift itself and the payload together to a higher orbit . This trade - off allowed heavier loads to be transferred to the station . After the retirement of the NASA shuttle, the nominal orbit of the space station was raised in altitude . Other, more frequent supply ships do not require this adjustment as they are substantially lighter vehicles . </P> <P> Orbital boosting can be performed by the station's two main engines on the Zvezda service module, or Russian or European spacecraft docked to Zvezda's aft port . The ATV has been designed with the possibility of adding a second docking port to its other end, allowing it to remain at the ISS and still allow other craft to dock and boost the station . It takes approximately two orbits (three hours) for the boost to a higher altitude to be completed . Maintaining ISS altitude uses about 7.5 tonnes of chemical fuel per annum at an annual cost of about $210 million . </P>

What height does the international space station orbit