A widely circulated comment by the chief of Russian space agency Dimitry Rogozin has ignited fears that the tension following Russia’s invasion of Ukraine could have consequences for the International Space Station (ISS), a permanent laboratory in space where the United States, Russia and some other countries work as partners.
In a threatening series of tweets, Rogozin said that Russia could respond to the US sanctions by letting the ISS fall from space. He said the ISS, a 420-tonne spacecraft, the largest man-made structure in space, could drop over US or Europe, or over India and China. Its orbital flight path usually does not take it over most of the Russian territory.
ISS
The International Space Station is the only operational space laboratory as of now, orbiting the earth in a trajectory that is about 400 km above the land surface. It is operated by more than 15 partner countries. Apart from Russia and the United States, Canada, Japan and several members of the European Space Agency are partners in the ISS.
The football-field-sized ISS travels at a speed of about 28,000 km per hour. It completes one journey around the earth in about one and a half hours. In one day, therefore, it makes about 16 trips around the world.
The ISS has been manned continuously since the start of operations in 1998. At any given time, there is a crew of six astronauts on board. Right now, seven astronauts, four from the United States, two from Russia (it prefers to call them cosmonauts) and one from Germany, are at ISS. According to NASA, 240 individuals from 19 countries have so far been to the ISS. The facility is used for carrying out a variety of zero-gravity experiments, space exploratory studies, and technology development.
The ISS is not the first space station to be built and operated. Several smaller space stations have been used earlier, the most famous of which have been the Russian Mir space station that operated in the 1980s, and the American Skylab.
The ISS has been in operation since 1998 and is expected to continue at least till 2028. Russia, however, has indicated that it might pull out of the collaboration earlier, possibly by 2024. Replacements for ISS are already being planned. Several countries including India and China have a desire to put their own space stations. China has already tested at least two prototypes.
The threat
The threat from chief of Russian space agency emanates from the fact that Russia provides the propulsion system of the ISS which keeps it in the pre-defined orbit. The ISS has two broad segments, one each managed by the United States and Russia. While the US manages power and the systems that make the spacecraft habitable, Russia is responsible for keeping it in orbit.
ISS is not entirely in zero-gravity space. It does encounter a little bit of gravity. Also, it loses a bit of energy as it moves around the earth. Left to itself, the ISS would fall down. The Russians periodically send thrusters that attach themselves to the ISS and impart the required momentum to keep it going.
Rogozin’s threat implied that the US and other countries would not be able to keep the ISS from falling down if Russia withdrew its support. Incidentally, Elon Musk, the billionaire owner of SpaceX, the largest private space enterprise which has been carrying both astronauts as well as cargo to the ISS, responded by saying that his company could step in and provide the propulsion to the facility in case the Russians abandoned it.
US-Russia space cooperation
The ISS is the most visible part of a wide-ranging space collaboration between US and Russia. The ISS partnership has so far remained immune from geopolitical tensions that regularly prevails between the two countries. For example, the previous crisis in Ukraine, when Russia had annexed Crimea in 2014, did not have any impact on the ISS collaboration.
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This time too, Rogozin’s threat is not being seen as something that Russia was seriously contemplating to do, and NASA played it down. But the present conflict does have the potential to affect space cooperation in other ways.
Already, there are reports that Russia might decide to keep the United States out from a planned mission to Venus, which the two countries were working to send together. The Venera-D mission to Venus is planned for 2029, and till now it was supposed to be a joint US-Russia mission.