Dr Jongrae Kim explains what to expect from China's falling space station
Dr Jongrae Kim speaks to Sputnik, a modern news agency, about China's space station which will fall down to earth in the next few weeks.
The Tiangong-1, China's first space station will crash down to earth between March and April 2018 according to experts, who also say that the debris could hit Europe, the US, Australia or New Zealand. Dr Jongrae Kim discusses what happens when debris enters the earth's atmosphere and what we should expect when the debris plummets into earth. The China National Space Administration (CNSA) reported in 2016 that they had lost control of Tiangong-1 and were unable to perform a controlled re-entry, meaning the station would eventually be pulled back towards earth and crash into the planet.
Dr Jongrae Kim, School of Mechanical Engineering, summarises how this can occur:
"All satellites in the near earth orbits experience various external disturbances including gravitational perturbations, the solar radiations, and the drag caused by air particles. Time to time, hence, a satellite must perform orbit manoeuvring to maintain its desired altitude or perform a de-orbit procedure (intentional destroy of a satellite after its life ended; this is, hence, a controlled crash by losing the significant amount of the kinetic energy by thrusters during a short period of time). Tiangong-1, supposed to be de-orbit after its operation ended, has been malfunction in the communication and the Chinese space agency cannot perform the controlled de-orbit.
The space station has been slowly losing the kinetic energy and eventually, its altitude is low enough that the air drag becomes significant. When it happens, the station will enter the earth atmosphere and most of the station parts would be burnt in the air. This would be no problem for most of small size satellites but the Chinese Space station is quite big and some parts might hit all the way down to the ground. However, the chance that these would hit the human, buildings, etc. is very small as the surface of Earth is, in fact, very big and most areas are not inhabited by people.
The prediction when it happens is very difficult because it loses a tiny amount of its kinetic energy every instance when it hits by air particles for example, where the air density is very low in the current altitude of the station. The orbit prediction with these tiny magnitude of forces is extremely challenging. At the moment, the ESA (European Space Agency) announces its prediction every 1 or 2 days. This would be more frequent and accurate as the crash time being closer."
Read the full interview with Dr Jongrae Kim on the Sputnik website.