Christine Coffey reports on the recent uncontrolled re-entry of China’s first space-station prototype.
Tiangong-1, (or Heavenly Palace 1), China’s first space station prototype, was functional for two and a half years and had been in orbit since September 2011, before it fell to a fiery and uncontrolled end after passing through the Earth’s atmosphere last week. This was to be the first in a series of test space stations in the ambitious Chinese space programme to “help master key rendezvous and docking technologies,” before sending up a larger model sometime after 2020.
When the first estimates stated that the 8,500 kg space-laboratory module would fall towards earth sometime between March 31st and April 1st, people were not reassured by statements such as “the orbiter would burn up in the atmosphere eventually.” Most of the debris fell into the Pacific Ocean, northwest of Tahiti, and thankfully no Pacific islanders were harmed in the re-entry of this space station.
“Most of the debris fell into the Pacific Ocean, northwest of Tahiti.”
According to the New York Times, this was an uncontrolled re-entry as communications with the space station were lost in 2016, and they were unable to guide it for the final part of the journey. Since the loss of communication, the orbiter has spent the majority of the last two years circling the planet at distances between 300-390 kilometres above sea-level in a rather redundant fashion, not sending any messages or recording any data (or so they claim) and not crashing into any satellites. Many private companies and other agencies tried to predict potential hit zones, stretching from South America to Africa, and from the Middle East to central Asia. The orbiter was moving quickly, and this resulted in a broad range of possible landing sites. Most of the space station didn’t make it through the earth’s atmosphere before burning up, meaning there was very little chance of being hit by falling space waste. According to the European Space Agency, “the personal probability of being hit by a piece of debris from Tiangong-1 is actually 10 million times smaller than the yearly chance of being hit by lightning.”
“According to the New York Times, this was an uncontrolled re-entry as communications with the space station were lost in 2016.”
This is not the first space station whose communication systems have come up second best against our atmosphere. NASA’s Skylab had a similarly uncontrolled re-entry in 1979 and a few Western Australians experienced unusual weather conditions and managed to escape the falling debris. Keeping control of orbiters upon re-entry is evidently difficult, but not impossible, as ESA have guided five cargo spacecrafts into uninhabited regions of ocean since 2008 and the Russian’s managed to steer the remainder of the Russian Mir station into the Pacific in 2001. The Chinese multi-billion-dollar programme have another non-permanent space station currrently orbiting the planet. Hopefully they can keep control of its landing.