The craft is now at about 300 km altitude in an orbit that wThere is a chance that a small amount of Tiangong-1 debris may survive reentry and impact the ground. Should this happen, any surviving debris would fall within a region that is a few hundred kilometers in size and centered along a point on the Earth that the station passes over. The map below shows the relative probabilities of debris landing within a given region. Yellow indicates locations that have a higher probability while green indicates areas of lower probability. Blue areas have zero probability of debris reentry since Tiangong-1 does not fly over these areas (north of 42.7° N latitude or south of 42.7° S latitude). These zero probability areas constitute about a third of the total Earth’s surface area.
Credit: The Aerospace Corporation’s CORDS

A leading Chinese space engineer has been reported to indicate that the country’s Tiangong-1 space lab is not out of control.

“We have been continuously monitoring Tiangong-1 and expect to allow it to fall within the first half of this year,” explains Zhu Congpeng, an engineer at the China Aerospace Science and Technology Corporation, notifying the state-run Science and Technology Daily newspaper.

Artist’s view of China’s Tiangong-1 space station in Earth orbit.
Credit: CMSA

“It will burn up on entering the atmosphere,” Zhu said, “and the remaining wreckage will fall into a designated area of the sea, without endangering the surface,” he said, remarks also relayed via a January 7 story by Reuters.

Plot predictions

Meanwhile, a January 3 plot by The Aerospace Corporation’s Center for Orbital and Reentry Debris Studies (CORDS) notes that Tiangong-1 is predicted to reenter in mid-March 2018, plus or minus two weeks.

CORDS is sponsoring a “live on green event” guessing game. Entrants can compete for Aerospace swag with the closest estimate to the actual reentry date and time of China’s Tiangong-1 space lab.

Enter your information for a chance to win some Aerospace booty with the closest guess to the actual reentry date and time of China’s Tiangong-1.

Submit your guess by going to:

http://www.aerospace.org/cords/live-on-green/

Heavenly palace

Tiangong-1 is the first space station built and launched by China. It was designed to be a crewed lab as well as an experiment/demonstration for the larger, multiple-module space station.

Docking of China’s Shenzhou 10 spacecraft with the Tiangong-1 space station June 13, 2013.
Credit: CCTV

Tiangong-1 (whose name means “Heavenly Palace” in Chinese) was rocketed into Earth orbit in late September 2011.

The first Chinese orbital docking occurred between Tiangong-1 and an unpiloted Shenzhou spacecraft on November 2, 2011. Two piloted missions were completed to visit Tiangong-1: Shenzhou 9 in June 2012 and Shenzhou 10 in June 2013.

International campaign

Experts at the European Space Agency (ESA) are hosting an international campaign to monitor the reentry of the Tiangong-1, conducted by the Inter Agency Space Debris Coordination Committee (IADC).

IADC comprises space debris and other experts from 13 space agencies/organizations, including NASA, ESA, European national space agencies, Japan’s JAXA, India’s ISRO, the Korea Aerospace Research Institute (KARI), Russia’s Roscosmos, as well as the China National Space Administration.

Owing to the Chinese station’s 18,740 pounds (8,500 kilograms) and construction materials, there is a distinct possibility that some portions of the Tiangong-1 will survive and reach the surface, according to a previous ESA statement.

The vessel will inevitably decay sometime between January and March 2018, when it will make an uncontrolled reentry,” the November 6, 2017 press statement explains.

Artist’s concept of the Tiangong-1 in Earth orbit.
Credit: CMSA

Emergency preparedness plans

In a December 8 communiqué from the Permanent Mission of China to the United Nations (Vienna), China has made note of the upcoming re-entry into the atmosphere of Tiangong-1.

“Currently, it [Tiangong-1] has maintained its structural integrity with stabilized attitude control,” notes the communiqué.

“China attaches great importance to the re-entry of Tiangong-1. For this purpose, China has set up a special working group, made relevant emergency preparedness plans and been working closely with its follow-up tracking, monitoring, forecasting and relevant analyzing,” the communiqué explains.

Confusion

“I think the confusion comes from the fact that control is limited to the attitude of the space lab – but not to the orbit,” explains Holger Krag, Head of the Space Debris Office for ESA in Darmstadt, Germany.

Attitude control has (hardly) no impact on the orbit, Krag said, “and a deorbit impact point cannot be achieved. Orbit control requires a meaningful propulsion function, which is not available/defunct,” he told Inside Outer Space.

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