The other day I got into a discussion about the International Space Station (ISS), namely where does its crew come from. I started reading up on it and I figured that it is worth a quick visualization. So I’ve created an interactive one, in echarts. The data comes from here and the code is here.
The ISS has been designed to hold a crew of 7. However, that has happened only rarely, with sometimes the crew size rising up to 9 for a few days, during mission changes. ISS missions are designed to last about half a year, but of course their actual duration will vary on the launch windows and rocket failures. Missions usually overlap a few days with each other, so during crew change periods, the population merely doubles.
Did you know the ISS has been crewed continuously for almost 20 years? In the commissioning phase, Between October 2000 and March 2003, its permanent crew was 3, with American NASA 🇺🇸 astronauts and Russian Roscosmos 🇷🇺 cosmonauts rotating in a 2-1 pattern. Then, after the Columbia disaster, this was reduced to 2, before slowly starting to climb back up from May 2006.
Around this time, astronauts of nationalities other than American 🇺🇸 or Russian 🇷🇺 started to crew the station, from ESA of Europe 🇪🇺, JAXA of Japan 🇯🇵 and CSA of Canada 🇨🇦. The ISS reached its designed capacity of 7 in July 2009.
However, with the end of life for the Space Shuttle, the maximum number of people that can safely evacuate from the station using the Soyuz is 6 – and therefore the permanent crew is limited to that. Interestingly, during a crew change in November 2013, there have been a total of 9 people on the station for 3 days!
Since the stabilization of the permanent crew at 6 starting with 2011, the general pattern has been to allocate these 6 slots to 3 Russian 🇷🇺 cosmonauts, 2 American 🇺🇸 astronauts and one other astronaut: with this remaining space allocated to Japan 🇯🇵 for about half of the missions and a crew member from Europe 🇪🇺 or Canada 🇨🇦 sharing the other half.
However, one can notice an interesting switch-over starting with August 2017, from when American 🇺🇸 astronauts started to take up 3 spaces and Russian 🇷🇺 cosmonauts reduced to 2.
That’s all for today – explore the interactive graph, too!