Sea burials: Where space stations, rockets rust in peace – YourStory

After a week of speculation, the core stage of a Chinese Long March 5 rocket, dubbed CZ-5B, landed inan uncontrolled reentryin the Indian Ocean near the Maldives. The rocket had transported part of China's new space station into orbit.

But its core stage about 30 meters long and 5 meters in diameter could have landed anywhere, even on land.

A year ago, a pipe from a previous Long March 5 rocket reportedly landed on someone's house in Cote D'Ivoire. Hence, all the fear andcriticism this year.

Nelson is not alone with his opinion. But the picture is more complicated than that. And the US is by no means innocent.

"There is no doubt," saysAlice Gorman, an associate professor at Flinders University in Adelaide, Australia, and author ofDr Space Junk vs the Universe, that "China has been a bit naughty."

Chinese aerospace experts rejected any international concern before the rocket core came down on May 9. One expert, Song Zhongping, wasquoted in the Global Timesas saying that it was "completely normal" for rocket debris to return to Earth.

And Zhongping is right it is quite normal for bits of rocket, satellites and even space stations to splash back down. And China's not even the worst offender. There are other nations and commercial companies doing it, too.

The majority of space junk lands somewhere in the ocean. That's simply because there's more ocean than land.

Mission designers will target specific regions, such as the South Pacific Ocean Uninhabited Area (SPOUA), near Point Nemo.

Point Nemo is one of the Earth's "poles of inaccessibility." It is the farthest point from land in any direction on the planet.

Ina blog post from 2018, the European Space Agency writes that more than 260 spacecraft have fallen in that zone since 1971. The number increases annually.

Perhaps unsurprisingly, Point Nemo is known as the "spacecraft cemetery." But it's not the only ocean region where spacecraft fall.

"Point Nemo? It's sort of there, but it's like everywhere in the South Pacific between New Zealand and Chile," saysJonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, USA.

"The punchline is that it's not very concentrated," McDowell told DW. "And, more and more now, people are using [other spots].

Where and how you come down depends on where and how you go up.

On some missions, the main stage of a rocket will remain "suborbital" in space at over 100 kilometers (62 miles) above sea level but below Low-Earth Orbit at about 160 km, and that makes it easier to drop rocket stages in a controlled way.

Even then, however, things can get precarious, especially when rockets are launched in-land, rather than from a coast.

A number of boosters have fallen near populated areas in China, once near an elementary school, and at a test site in Kazakhstan. Both cases released toxic orange clouds of what's called "BFRC."

Once a rocket enters orbit, things get more complicated. And the deeper a rocket goes, the harder it gets to deorbit.

It's more expensive, because you have to keep the rocket alive, as it were, with extended battery life and/or a restartable engine that gets fired after the rocket has delivered its "payload" a satellite or supplies for the International Space Station.

But only then can you control its reentry. Many rocket stages just get left up in orbit.

It all depends. And it bears repeating that China's not the only "naughty" nation. McDowell estimates there are about 20 Falcon 9 upper stages "in orbit as junk that will eventually reenter" in some form or other.

There is a trend in the industry to change, says McDowell. It wants to leave less debris in space for fear of a growing congestion that could either interfere with earthly communications systems or impede further space exploration.

But that means more stuff will have to come down. There is even talk of deorbiting the International Space Station in 2028, and dropping it at a final resting place in the South Pacific.

The impact on the ocean is despite assertions that space junk becomes nice, natural habitats for marine life largely unknown.

When junk falls atBaffin Bay, an icy point off Greenland, the threat to local seal, whales, bears and walrus, is under-researched.

In the South Pacific, scientists havediscovered and revived 100-million-year-old microbial lifeat theSouth Pacific Gyre essentially the same region as Point Nemo.

That microbial life may mean little to our daily lives, but microbes at extreme environments, such as hydrothermal vents, do sustain other life, such as the yeti crab, and may have even played their part in the origins of our own, human life.

"Some spacecraft fuels are toxic hydrazine, for example. But cryogenic fuels are not toxic," says Gorman. "There are metals like beryllium and magnesium, they are usually in alloy form, but beryllium is pretty nasty no matter what."

So, there are potential environmental impacts, says Gorman, "but I don't think people have thoroughly assessed that yet."

(This article by author Zulfikar Abbany was originally published on Deutsche Welle.)

(Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the views of YourStory.)

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Sea burials: Where space stations, rockets rust in peace - YourStory