China’s Tiangong-1 (or Heavenly Palace) space station made a fiery return to Earth, crashing into the South Pacific on April 1 and ending its 6½-year sojourn through space. The mission was a milestone in China’s space program and a stepping stone in its off-world ambitions. Tiangong’s end is also an important reminder of the need for an international regime to deal with space debris. The vital importance of outer space to modern economies demands cooperation among governments here on Earth.
The 9.4-ton spacecraft, about 12 meters long with a volume of 15 cubic meters, was launched Sept. 29, 2011, into an orbit about 350 km above Earth. Its main purpose was to help China develop and polish the skills and technologies necessary to sustain an ambitious space program. An unmanned spacecraft docked with the space station in November 2011, less than two months after it was launched. In June 2012, a crew of three taikonauts — Chinese astronauts — traveled to the station for two weeks; a second crewed mission rendezvoused for another two-week stay in June 2013.
Tiangong-1’s mission was a success. Its anticipated life span was just two years, but it continued to transmit data to Earth until March 2016, when it went silent for reasons not yet disclosed by the Chinese government. The space station’s orbit gradually decayed — as anticipated — until its re-entry earlier this week.
China has already launched Tiangong-2, putting it into orbit in September 2016. Taikonauts visited a month later, as did a robotic vessel, which performed repeated docking and refueling operations. By all accounts, China is set to achieve its goal of having a permanently crewed space station in orbit by 2022. China previously announced plans to land a vessel on the far side of the moon in 2018 and bring back space rocks, an unprecedented mission. This is all part of a plan for China to become the leading power in space. It has already surpassed Russia in spending on its national space program, and could even eclipse the United States.
This is not just a vanity project. These feats demand technological and engineering prowess; the capabilities and components required to achieve these objectives and their potential spinoffs will be critical to the success of 21st century economies. Communications systems and national infrastructure depend on space.
Tiangong-1’s re-entry demonstrates a larger problem: that of space junk. It is estimated that there are some 14,000 uncontrolled objects larger than a softball in orbit around Earth. Every one of them is a potential hazard to other functioning objects in space, such as satellites. They, along with another 9,000 objects still controlled by governments and private companies, are tracked by national authorities and the Space Surveillance Network.
Russia has put the largest number of items in space, with the U.S. close behind: Each has more than 6,200 objects in orbit, and about two-thirds of them are uncontrolled. China has created 3,601 pieces of space junk. Japan is fifth on the list of countries producing space debris (following France), with 278 items in space.
Japan is something of a laggard when it comes to space programs. It has enjoyed recent success with its micro-satellites, but it has not made space exploration a national priority, and it has worked primarily with international consortia to advance Japan’s space interests. Recognizing that it needs to do more, and that the old model of state-based ventures is no longer viable, the government announced last month that it would establish a ¥100 billion fund to nurture space startups. The fund will provide financial support as well as match-making between investors and startup companies.
A priority for Japan, along with all other space-faring nations, is the cleanup of that space debris. The European Space Agency reckons that there could be as many as 670,000 bits of debris larger than a fingernail in space, and as many as 170 million pieces of junk larger than a millimeter. As those articles are whizzing around the planet at speeds exceeding thousands of kilometers per hour, even tiny objects can do great damage. Scientists fear that collisions can result in chain reactions, but even single collisions can render large swaths of space uninhabitable to satellites or other objects.
The primary obstacle to establishing a successful regime for cleaning up space debris is not technology but legal rights. The nation that sends an object into space retains ownership no matter what condition it is in. Touching or interfering with an object in space, even if this is done only in the act of disposing of it, could be considered an act of war. This must be remedied. And hopefully a treaty or international agreement to help clean up outer space can serve as the first step in a larger framework to ensure that outer space remains peaceful and demilitarized.
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