(Above: the ISS in 2009. Image public domain, source Wikimedia Commons)
This year’s Young Structural Engineers International Design Competition is challenging entrants to design a space station: here we look at the structure of the ISS.
1. The ISS has a total mass of about 450 metric tonnes and is the largest structure ever placed in orbit around Earth. The station has an internal pressurized volume of 915m³, or equal that of a Boeing 747. The station’s solar array wingspan (73m) is longer than that of a Boeing 777. ISS travels around the Earth at around 17,000mph.
2. Each solar "wing" is split into two photovoltaic blankets, each of which has 16,400 silicon photovoltaic cells. Each pair of blankets was packed like an accordion for delivery to space, then unfolded in orbit. Gimbals rotate the arrays to face the Sun and provide maximum power.
3. The main integrated truss is made up of 11 segments and a separate component known as Z1. It has a length of more than 108m, providing attachment points for external payloads (like modules from Russia, The United States, Europe and Japan) as well as carrying electrical lines and mobile transporter rails.
4. Although weightless, any structure in orbit has mass and inertia, and designers had to account for the Earth’s gravity acting upon the station. During construction ISS had to be arranged around the centre of mass so that it was aligned correctly and would not create attitude control problems. Here the design drew on lessons from previous space stations, like the Soviet Union’s Mir
5. The first pressurised module to be launched was Zarya
(Dawn) on 20 November 1998. The latest addition has been the Bigelow Expandable Activity Module
(BEAM) – an experimental module of 16m³ designed to test the value of “expandable habitat technology”.
Learn more about the Young Structural Engineers International Design Competition and make your entry.