China lost control of its
first space station, Tiangong-1, or "Heavenly Palace" in 2016. The
spacecraft should burn up in Earth's atmosphere on April 1, give or take four
days. Chunks of the 9.4-ton vessel should be durable enough to reach our
planet's surface. Any surviving pieces of Tiangong-1 will most likely land in
the ocean.
China's first space
station, called Tiangong-1 or "Heavenly Palace," will soon explode
over Earth into a fiery rain of space junk.
The Aerospace Corp., a
nonprofit spaceflight research company, has released its newest predictionabout
the derelict spacecraft's doom. Tiangong-1 may reenter Earth's atmosphere on
April 1, give or take four days — which means the dead spacecraft could come
crashing down as soon as Wednesday, March 28.
When it does, extreme heat
and pressure caused by plowing through the air at more than 15,000 mph will
destroy the roughly 9.4-ton vessel. Not everything may vanish, though. There's
a good chance that gear and hardware left on board 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 Corp., 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."
For example, he said, after
NASA's Columbia space shuttle broke up over the US in 2003, investigators
recovered a working flight computer — an artifact that ultimately helped
explain how the deadly incident happened. Launched on Sept. 30, 2011,
Tiangong-1 is a two-room space station for two taikonauts, or Chinese
astronauts. It has a volume of 15 cubic
meters, or about 1/60th of the volume of the International Space Station, which
is about as long as a football field.
Though China superseded
Tiangong-1 in 2016 with Tiangong-2, space experts hailed it as a major
achievement for the nation's space program, since it helped pioneer a permanent
Chinese presence in orbit.
"It conducted six
successive rendezvous and dockings with spacecraft Shenzhou-8, Shenzhou-9, and
Shenzhou-10 and completed all assigned missions, making important contributions
to China's manned space exploration activities," said a memo that China
submitted in May 2017 to the United Nations Committee on the Peaceful Uses of
Outer Space.
In the memo, China said it
lost contact with the spacecraft on March 16, 2016, after it "fully fulfilled
its historic mission." By May 2017, Tiangong-1 was coasting about 218
miles above Earth and dropping by about 525 feet a day, the memo said. Its
altitude has since plummeted to an altitude of about 140 miles, according to
the Aerospace Corporation's latest data, published on March 20, 2018.
"For any vehicle like
this, the thing that brings them down is atmospheric drag," Ailor said.
"Why there's a lot of uncertainty in the predictions is that it depends on
what the sun's doing, to a large measure."
The sun can unleash solar
storms and solar flares — bursts of X-rays and ultraviolet light — that heat
Earth's outer atmosphere, causing the air to expand and rise. That forces
low-flying objects like Tiangong-1 to plow through denser gases.
"This puts just a
little bit of a higher force on these objects that causes them to come
down," Ailor said. An analysis of the combined effects of solar activity
and Tiangong-1's orbital speed, direction, and altitude, as well as other
factors, helped the Aerospace Corporation provide its most recent estimate of
an early-April de-orbit.
Before the big moment,
however, the company will refine its estimates as conditions in space change. Tiangong-1
is likely to crash over the ocean, as water covers about 71% of Earth's
surface. But there's a decent chance some pieces may strike land as it breaks
up over a long and thin oval footprint.
"The whole footprint
length for something like this could be 1,000 miles or so," Ailor said, with
heavier pieces at the front and lighter debris toward the back.
If anyone is lucky enough to
witness Tiangong-1's atmospheric breakup from an airplane, it may look similar
to the destruction of the European Space Agency's 14-ton Automated Transfer
Vehicle. The ATV was an expendable spacecraft that used to resupply the ISS.
Once astronauts and cosmonauts unloaded its supplies, it was filled with
garbage and sent careening back to Earth.
When asked for comment on
Tiangong-1's threat to ongoing NASA missions, the space agency told Business
Insider it "actually doesn't track any debris."
Ailor says pieces of China's
space station are "really unlikely" to hit anyone or anything on
Earth. According to The Aerospace Corp.'s website, the probability "is
about 1 million times smaller than the odds of winning the Powerball
jackpot."
"It's not impossible,
but since the beginning of the space age ... a woman who was brushed on the
shoulder in Oklahoma is the only one we're aware of who's been touched by a piece
of space debris," he said. Should a hunk of titanium, a computer, or
another piece smash through a roof or windshield, however, international space
law covers compensation for victims. "It's China's responsibility if
someone gets hurt or property gets damaged by this," NASA's representative
said.
Via Bussinesinsider