[imagesource: Stringer / AFP]

The Long March 5B rocket was successfully launched from China’s space station last week, and now a large part of it is making its way back down to Earth, where it’s expected to land…somewhere.

The reentry will be uncontrolled and based on its predicted trajectory, the rocket and its parts could land anywhere from the far north of New York to Madrid, Beijing or as far south as southern Chile, or New Zealand.

It’s anyone’s guess at this point. To make matters worse, they haven’t ruled out the fact that it could ‘land’ in an inhabited area.

According to SpaceNews, it is not usual for the first stages of expendable rocket to reach orbital velocity, reenter the atmosphere and land in a pre-defined reentry zone. We’ve seen this often with SpaceX rockets, although those aren’t expendable.

Some other larger, second stages perform deorbit burns to lower altitude to reduce time in orbit and lower chances of collisions with other spacecraft or to immediately reenter the atmosphere.

It was somewhat expected that the Long March 5B core would perform a deorbit, but this doesn’t seem to have happened – which the Commander-in-Chief of Long March 5B confirmed.

Spaceflight observer Jonathan McDowell told SpaceNews that he hoped China would have enhanced the core stage to perform a controlled deorbit after separating from Tianhe.

“I think by current standards it’s unacceptable to let it reenter uncontrolled,” McDowell said.

I’m sure everyone in the countries marked as possible reentry zones would agree.

Now designated 2021-035B (named after the roughly 30-metre-long, five-metre-wide Long March 5 core stage) is in a 170 by 372-kilometre altitude orbit travelling at more than seven kilometres per second.

This is not the first time that the Long March 5B has reentered uncontrolled. The first launch saw the first stage reach orbit and reentered over the Atlantic Ocean according to the US Space Force’s 18th Space Control Squadron.

There are many factors to consider when predicting where the Long March 5B stage will fall.

There’s atmospheric drag and fluctuations, the size and density of the object, the influence of solar activity and much more.

The rocket is moving so fast that it orbits Earth roughly every 90 minutes, which means that any change during reentry, even by a few minutes, could hurtle it thousands of kilometres away.

As mentioned before, this could be anywhere from New York to New Zealand.

Hopefully, any debris surviving the intense heat of reentry falls into the oceans or uninhabited areas.

As long as there is no harm to anyone or anything, a nighttime reentry could make for spectacular viewing.

[source:spacenews]