Monday, 2 April 2018

Tech: The Chinese space station hurtling towards Earth has crashed over the South Pacific

An illustration of China's first space station, Tiangong-1, orbiting Earth.

China's spacecraft Tiangong-1, a name that means "Heavenly Palace," has reportedly crashed back into Earth's atmosphere over the South Pacific ocean.

  • The Chinese space station Tiangong-1 came crashing back into Earth's atmosphere at approximately 8:16 p.m. ET, over the southern Pacific ocean.
  • Tiangong-1, which translates as "Heavenly Palace" in English, was China's first station launched into space.
  • Tiangong-1 was used to practice docking maneuvers and was visited by two crews of taikonauts, or Chinese astronauts.
  • China lost control of the station in March 2016, then launched the Tiangong-2 space station into orbit later that year.

The first space station China launched into orbit is no more.

The space station Tiangong-1, which translates to "Heavenly Palace" in English, came crashing back into Earth's atmosphere at approximately 8:16 p.m ET over the southern Pacific ocean, according to numerous sources, including the Joint Force Space Component Command, a statement from China reported by the AFP, and the Aerospace Corp.

According to reports, the space station reportedly burned up in the atmosphere over the Pacific northwest of Tahiti, not far from the "spacecraft graveyard" where space agencies often try to land debris from spacecraft.

It's likely that debris is scattered over a long stretch of the Pacific in that region.

Tiangong-1's end has been coming for years now.

The station was first launched at the end of September in 2011 and had been visited twice by crews of taikonauts, or Chinese astronauts, in 2012 and 2013.

But in March of 2016, China lost contact with Tiangong-1. The space station's orbit has been slowly decaying since then. By May 2017, Tiangong-1 was coasting about 218 miles above Earth and dropping by about 525 feet a day.

It was then just a countdown to figure out when and where it would break up in Earth's atmosphere.

The end of a space station

Tiangong-1 was a schoolbus-sized 9.4 ton spacecraft — about 34 feet long with a volume of 15 cubic meters, or about 1/60th of the volume of the International Space Station, which is the length of a football field.

When space stations come down, "a funny thing" happens that helps doom the spacecraft, Jesse Gossner, an orbital-mechanics engineer who teaches at the US Air Force's Advanced Space Operations School, previously told Business Insider.

"You start going really, really fast," he said. "Then you get slowed down really, really fast."

That's because the spacecraft is losing its forward speed, allowing gravity to accelerate the space station toward Earth. The air is still too thin to slow it down much, so it plummets faster and faster.

As the spacecraft falls into thicker air, the drag slows it down and begins to rip off solar panels, antennas, and other loosely attached pieces. Superheated plasma heats the vessel to thousands of degrees, melting and disintegrating it.

Only a few types of materials, like titanium, can withstand such punishment.

There is a chance that some gear and hardware left aboard could survive intact all the way to the ground, according to Bill Ailor, an aerospace engineer who specializes in atmospheric reentry. That durability is thanks to Tiangong-1's onion-like layers of protective material.

"The thing about a space station is that it's typically got things on the inside," Ailor, who works for the Aerospace Corporation, previously told Business Insider. "So basically, the heating will just strip these various layers off.

"If you've got enough layers, a lot of the energy is gone before a particular object falls out, it doesn't get hot, and it lands on the ground."

According to the statement from China quoted by AFP, the station was "mostly destroyed" upon re-entry.

What happens to the debris

The chances that debris from the station would hit a person or even end up on land were infinitesimal from the start.

According to The Aerospace Corp.'s website, the probability of being hit was "about 1 million times smaller than the odds of winning the Powerball jackpot."

But if a hunk of titanium, a computer, or another piece smashed through a roof or windshield, international space law would cover compensation for victims.

"It's China's responsibility if someone gets hurt or property gets damaged by this," a NASA representative previously told Business Insider.

If intact material from the station is recovered, it's still Chinese property.

Any debris that made it to Earth would be all that remains of the station China first launched as a step towards creating a permanent presence in space. In 2016, Tiangong-1 was superseded by Tiangong-2. And China is now considering plans to build a much larger space station in 2023.

While space debris usually burns up in Earth's atmosphere and is generally unlikely to hit a person, the Tiangong-1 crash serves as a reminder that there's a real space junk problem. Before its fiery demise, Tiangong-1 was just one of 14,000 uncontrolled objects larger than a softball in orbit around our planet — something experts say is a real problem with potentially scary consequences.

Now there's one fewer object to worry about.

More on the crash of Tiangong-1:

Tech: The Chinese space station hurtling towards Earth has crashed over the South Pacific