Where will the out-of-control Chinese space station land?Scientists have admitted that they have no way of safely guiding Tiangong-1 back to Earth, and say it is moving too fast to accurately predict where debris from the 8.5-tonne module will crash
What is happening with the Chinese space station?
The nation’s first prototype space station, Tiangong-1, or “Heavenly Palace”, launched into orbit in September 2011. The module reached the end of its service life earlier this year and was due to splashdown – eventually – in the Pacific Ocean. But at a recent press conference, the Chinese space agency admitted it had lost contact with the station. They did not explain what had gone wrong.
Does losing contact matter?
It depends what the Chinese planned to do next. If the agency was going to let the spacecraft simply fall to Earth in an uncontrolled way and burn up in the atmosphere, then the loss of contact means little. But if they had intended to perform a controlled de-orbit, that option is now gone. Controlled de-orbits tend to be reserved for spacecraft that pose a potential risk to people when they fall back to Earth. If the chances of someone being injured by components that survive the fireball of re-entry is greater than one in 10,000, then the spacecraft should be actively steered into a region of the South Pacific known in the business as the “spacecraft graveyard”. The module is already below the altitude of the International Space Station (ISS) and so there is no risk of a collision on its way down.
What was Tiangong-1 for?
Unlike the massive ISS, which is the size of a football field and has the living space of a five-bedroom house, Tiangong-1 is a mere 10 metres long and 3 metres wide. The Chinese used the module to practise rendezvous and docking procedures, and several taikonauts, including two women, spent time aboard after catching a ride on the Shenzhou spacecraft. Losing control of the module is more of an embarrassment to the Chinese space agency than a blow to their space programme. Two weeks ago, in a long-scheduled launch, the Chinese put another space station module, Tiangong-2, into orbit, and a crew of at least two taikonauts is expected to visit as early as next month. The agency still hopes to build a 55-tonne space station by 2020.
Will the stricken module survive re-entry?
Satellite tracking radar show the Chinese module at 380km high and travelling at 27,500km per hour. At that speed and altitude, it could lap the planet 5,000 more times before it starts to feel the drag of the upper atmosphere and begin its final descent. Most of the 8.5-tonne module will burn up from aerodynamic heating in the Earth’s atmosphere. But the Chinese space agency has conceded that some heat-resistant components may survive. “The module is predominantly a hollow shell, so there’s a good chance a significant portion will burn up in the atmosphere. But there’s also a chance some elements will survive down to surface,” said Hugh Lewis, a space debris expert at University of Southampton.
Where will it come down?
No one knows. And the vagaries of re-entry mean it will be impossible to predict with accuracy, even in its final moments. Computer simulations cannot tell far in advance on which orbit a spacecraft will re-enter. The Tiangong-1 is moving fast, at a shallow angle relative to the atmosphere, and the height of the atmosphere at any point depends on the regional temperature. But even when an object has begun its descent through the atmosphere, the final resting place of debris is still hard to predict. How the spacecraft tumbles through the atmosphere has an influence on how it breaks up. The most space agencies can do is calculate a debris ellipse where fragments are expected to land.
Are we in danger?
Pieces of space debris fall to Earth every day, but most of these are small fragments. Now and again, whole satellites or rocket stages tumble out of orbit and break apart in the sky. The most dangerous uncontrolled re-entry happened in 1979 when Nasa’s 85-tonne Skylab space station came down over Australia. In 2001, when the Russian Mir space station had reached the end of its life, Roscosmos de-orbited the 135-tonne outpost into the Pacific. But even with so much hardware raining from the skies, no one is known to have been hurt by falling space junk. “It is luck, but it proves that luck is on our side,” said Lewis. The odds are wildly in favour of not being hit because most of the Earth’s surface is covered with water, and most of the world’s population is crammed into a small percentage of land. The chances of a specific individual being struck by falling debris is trillions to one, making death by lightning far more likely.
Three Words: Chinese. Space. Station.
China just put another small space station into orbit—and by the 2020s they may replace the International Space Station. But private companies are the future of space exploration.
China has just launched its second small Tiangong space station into orbit, more or less catching up to what the United States’ and Russia’s own space programs achieved starting in the 1970s.
Riding atop a Long March rocket, the 34-foot-long, 10-ton Tiangong-2 blasted off from the Jiuquan Satellite Launch Center in northwest China on Sept. 15, aiming for an orbit 240 miles over Earth’s surface.
While Beijing’s effort to establish a long-term human presence in orbit is impressive on a political level, on a technological level it’s decades behind the curve. In the United States and elsewhere, private companies are poised to establish a long-term presence in space that doesn’t depend on big, government-run orbital structures.
“China is currently doing nothing in space that the U.S. hasn’t done already, much sooner, and often with a much higher level of technological sophistication,” Joan Johnson-Freese, a professor at the U.S. Naval War College and a space expert, told The Daily Beast.
In the race to build orbital habitations, Russia actually beat the United States by a few years when it launched the first of several Salyut stations beginning in 1971. America’s first space station was Skylab, which lasted six years starting in 1973. Today Russia and the United States work together on the International Space Station, which began operation in 1998 and has expanded to include dozens of modules capable of supporting six crew in total, year-round.
Compared to the International Space Station, the single-module Tiangong stations are tiny.
The plan is for a pair of Chinese astronauts to visit Tiangong-2 in October and stay for a month or so—an improvement over the Tiangong-1 station, which managed to support two crew for just eight days in 2012 and 12 days in 2013.
Tiangong-1, China’s first space station, launched in 2011 and decommissioned back in March amid rumors of a technical malfunction. Chances are the older station will plummet back to Earth sometime in 2017 as its orbit decays.
Like its predecessor, Tiangong-2 is supposed to last just a few years. Its replacement could be a third Tiangong station that, like Tiangong-1 and -2, will be temporary. The Chinese space agency is planning to loft a fourth and much larger station in 2020 or later. Assuming the project succeeds, the fourth craft could become the basis of a large, long-lasting space station similar in scale to the International Space Station.
But don’t hold your breath. “The Chinese have quite a bit more work to do before they are ready to start assembling their space station,” Gregory Kulacki, a space expert with the Union of Concerned Scientists, told The Daily Beast. “It is possible they could complete that work by 2020, but my guess is that they will need more time.”
In any event, it’s possible the Chinese could have a large, sustainable space station up and running by the time International Space Station finally reaches the end of the line in the mid- to late 2020s. At that point, prolonging the International Space Station’s useful life would take a sizable injection of expensive new technology requiring significant political will. With NASA’s budgets flattening and U.S.-Russian relations at a low point, the space station could begin to look like a pricey liability in Washington and Moscow.
And that’s where China holds an advantage. Sure, the Tiangong stations are small and somewhat archaic—and the larger station they’re meant to support will merely duplicate what the International Space Station achieved in 1998. What’s impressive is that Beijing has managed to plug away steadily at its space stations, year after year, calmly weathering economic crises and political turnover.
Such stability is vital for space programs costing tens or hundreds of billions of dollars and requiring years or even decades of research and development. And in space the Chinese Communist Party has proved remarkably stable. “As many members of the Chinese space community have told me, China is not in a hurry,” Kulacki explained. “They are not racing anyone, and safety is a higher priority than meeting an arbitrary deadline.”
Indeed, the enduring domestic political support for China’s space stations could prove more important than the stations themselves for China’s future as a space power. By contrast, the United States—and, to a lesser extent, other spacefaring countries—is virtually assuming that political will for its own space program will collapse, and private companies such as SpaceX, Blue Origin, and Virgin Galactic will fill the vacuum.
There’s even a company building space stations. In April, Las Vegas space startup Bigelow Aerospace announced an ambitious plan to build at least two inflatable space stations and lob them into orbit starting in 2020. The B330 stations—each featuring its own power, life-support systems, and maneuvering thrusters arranged around a central metal frame—could function as space hotels, orbital factories, and zero-gravity research labs.
CEO Robert Bigelow said he wants to attach the first B330 to the International Space Station in order to expand the station’s volume by as much as a third and, perhaps, help extend its usefulness beyond its planned mid-2020s decommissioning date. “We are hoping we can get the permissions necessary from NASA to say, ‘Yes, let’s attach it,’” Bigelow said.
But even if NASA says no, Bigelow said he will continue developing his inflatable stations. There’s plenty of incentive to do so. Asteroid- and moon-mining—and the associated orbital manufacturing—could mean hefty profits for any company willing to make a big investment in space technology andassume a significant financial risk.
“The new space players such as Bigelow, SpaceX, and Virgin Galactic are the future,” Johnson-Freese told The Daily Beast. “The new space players aren’t reliant on political will. They operate on business plans, a much sounder practice and one that will eventually ‘normalize’ space as an area of industrial and geographic development.”
While China tinkers with old school, government-funded orbital stations, the United States—via private enterprise—is laying the foundation for a whole new approach to space exploration.
