Fortunately, the 20-ton booster returned to Earth in peace without causing any damage or casualty
The Chinese Long March 5B booster that has dangerously been hanging over the Earth for days — finally dropped into the Indian Ocean near the Maldives early on Sunday, ending days of speculation over where the debris would hit.
Fortunately, the 20-ton booster returned to Earth in peace without causing any damage or casualty.
However, there was no guarantee the Chinese booster would land harmlessly in an empty patch of ocean. Scientists and experts were not sure about the exact place where the debris will hit until the last moment.
Although the uncontrolled re-entry of the Chinese Long March 5B booster did not cause any damage, the incident sparks discussion of a more dangerous and growing problem of space debris and the sustainability of growing national and private space programs.
What is space debris?
Space debris or junk has been amassing since the decade of 1960s, when the first human-made satellite, Sputnik 1, was launched by the USSR on October 4, 1957.
This momentous incident was the start of the space age.
According to Nasa, more than 4,700 launches have been conducted worldwide since then. These launches have widened the exploration of human in space, however, that also means we've left our mark on space in the form of trash.
An estimated 9,300 tons of space junk is already orbiting the planet from a few hundred kilometres to more than 35,000 kilometres in altitude.
The junk ranges from old satellites, rocket bodies, fragments and particles to smaller bits and pieces lost to space, including nuts and bolts, garbage bags, lens caps, and even screwdrivers.
Most of these junks are circling the earth in its lower orbit. They can ultimately lose altitude over time and incinerate in the atmosphere.
According to the European Space Agency (ESA), about 6,900 of 11,370 satellites placed into Earth orbit are still circulating, with about 4,000 functioning.
And the number of debris objects regularly tracked by Space Surveillance Networks under the United States Department of Defence stands at 28,160.
Are we in danger?
Since the late 1970s, pieces of space debris have fallen to Earth regularly and are viewed with increasing concern.
Apart from the fact that 70% of our planet earth is covered with water which lowers the chances of space debris falling in an inhabited area by a huge amount, there’s something else that protects us from most space debris: our atmosphere - which works like a firewall.
Incidents like space debris re-entering the atmosphere mostly go unnoticed because the debris burns up almost all the time before it can hit the ground.
ESA estimates that about 75% of large objects launched into space have already re-entered the Earth’s atmosphere, according to Global News.
“In the last 10 minutes before reaching the ground, the dense atmosphere starts to heat up and decelerate the object,” the ESA says.
“In the case of very compact and massive satellites, and if a large amount of high melting-point material is involved such as stainless steel or titanium, fragments of the vehicle may reach the ground.”
In 2002, Nasa had estimated that the chances of being hit by space debris were 1 in 3,200.
Though the chances of our roofs getting hit by space debris are thin, 9,300 tons of space junk already orbiting the planet and the issue of space collisions and debris pollution remain a matter of concern.
How to reduce space junk?
Many countries and private organizations have been working to reduce the amount of debris from Earth’s low orbit.
Astroscale, a UK-based private orbital debris removal company, is currently displaying a vehicle called “ELSA-d” in lower Earth orbit to show that space debris clean-up is indeed possible.
According to Astroscale Managing Director John Auburn, the task is fiendishly difficult, especially if the target satellite is spinning and tumbling.
“The big problem in space is not big debris, but when big debris breaks up and becomes small debris,” Auburn told The Guardian.
JAXA, Japan's space agency, is testing an electronic space whip, which stretches six football fields long, to knock debris out of orbit, sending it to burn up in Earth's atmosphere, according to National Geographic.
A Chinese space mining start-up also launched, into low Earth orbit last month, a robot prototype that can scoop up debris left behind by other spacecraft with a big net, according to Reuters.
Threats from outside of our planet are hardly a new phenomenon. Nature has been tirelessly pounding our planet with rock for more than four billion years.
Humans are giving the cosmos a real competition with an estimated rate of about 100 launches a year most of which will eventually come down crashing today or tomorrow.
With so many objects hanging above our heads, are we ready to tackle the rain of space debris?