Tiangong-1 Falls to Earth
The People’s Republic of China’s Manned Space Agency reported that its space laboratory module, Tiangong-1 (“Heavenly Palace 1”), re-entered the Earth’s atmosphere and burned up over the southern Pacific Ocean on Apr. 2, 2018. The destruction of the satellite marks the end of China’s first space station which was launched nearly seven years ago.
On Sept. 30, 2011, China launched its first space laboratory module from its Jiuquan Satellite Launch Center in Inner Mongolia. The unmanned module, weighing eight tons and dubbed “Tiangong-1,” was designed for an operational lifetime of two years, with several docking maneuvers and astronaut rendezvous missions planned for the space station. An unmanned docking procedure (Shenzhou 8) was carried out successfully in Nov. 2011 before two manned missions (Shenzhou 9 and Shenzhou 10), each lasting about 14 days, brought Chinese astronauts aboard Tiangong-1 in June 2012 and June 2013.
Beijing ultimately extended the operational mission time of the space station by another two years and began preparations for disposal of Tiangong-1. While China sought to dispose of its first space station through a “controlled re-entry” through the atmosphere that would allow for the spacecraft to completely burn up over an uninhabited portion of the globe, a vaguely-worded report by state-run Xinhua News Agency in Mar. 2016 stated that ground controllers had lost contact with Tiangong-1. Amateur satellite watchers hypothesized that Beijing had lost control of the satellite by the end of the same month, a claim that was ultimately confirmed by China’s Manned Space Agency in mid-Sept. 2016.
Objects orbiting the Earth in “low Earth orbit,” including the International Space Station, face atmospheric drag that slows their orbital velocity — orbital decay — and, if left unchecked, leads to the satellite burning up in the lower atmosphere or (in rare cases, such as Skylab in 1979) impacting the surface of the Earth. Ground controllers typically command orbiting spacecraft to fire its engines or thrusters for periods of time to reboost the craft back into its prescribed altitude and orbit.
In a press conference held on Sept. 14, 2016, Chinese officials estimated that the defunct station would fall to Earth “in the latter half of 2017,” with “most parts of the space lab” projected to “burn up during falling” and “unlikely to affect aviation activities or cause damage to the ground.”
The Permanent Mission of China to the United Nations in Vienna informed the Committee on the Peaceful Uses of Outer Space (COPUOS) in May 2017 about the Chinese loss of control over Tiangong-1; the decaying orbit of the space lab; and a new predicted re-entry date range of Oct. 2017 to Apr. 2018. At the request of Beijing, the Inter-Agency Space Debris Coordination Committee spearheaded the international effort to track and predict the re-entry of Tiangong-1.
Predictions in the final days of Tiangong-1’s descent could not establish a definite landing area for the defunct satellite, with nearly two-thirds of the world being in the potential re-entry zone. However, the European Space Agency noted that Tiangong-1 was most likely going to burn up over the Pacific Ocean and the likelihood of debris striking someone was infinitesimally small.
The bus-sized defunct space station finally met its fiery end above the skies of the southern Pacific at 16 minutes past midnight Coordinated Universal Time (5:16 PM Pacific Daylight Time) of Apr. 2, 2018. The United States Joint Force Space Component Command provided coordinates placing the re-entry near American Samoa (14°S, 164°W) while the Center for Orbital and Reentry Debris Studies at the Aerospace Corporation placed Tiangong-1’s final position closer to Tahiti (24.5°S, 151.1°W).