China's uncontrolled space debris

Speaking of China, there has been much speculation in recent days about exactly where bits of the the Chinese rocket Long March 5B would come down to earth. The Chinese rocket scientists had no idea, having lost complete control of it some time ago, but blithely opined that it would probably come down somewhere in one of the oceans, on the basis that 70% of the earth's surface is water. They say it is "very unlikely to cause any harm", which is a rather vague assurance.

If this seems to you like a bit of a cavalier and risky attitude, then you'd be quite right. About 80% of the empty core stage of the rocket was expected to burn up on re-entry into Earth's atmosphere, but this is a large and extrmely heavy object, estimated at between 18 and 22 tonnes, so that still leaves about 4 tonnes of metal debris to fall, God knows where.

Yesterday's Globe and Mail reported that, according to its expert sources, the rocket night be expected to hit the Pacific Ocean, somewhere near the equator. Other expert predictions have had it coming down somewhere in the Mediterranean basin, or possibly anywhere from Costa Rica to Australia. Clearly this is not a very exact science. Part of the problem is that the rocket fragment is orbiting the earth every 90 minutes or so, travelling at about 8 kilometres per second, so any slight difference in timing can make a huge difference in its geographical location.

In the end, Long March 5B landed safely in the Indian Ocean near the Maldives, nowhere near many of the earlier predictions.

This is the second time in a year that  Chinese rocket debris has fallen to Earth in a completely uncontrolled fashion. Long March 5B's predecessor fell on Ivory Coast in western Africa about this time last year, damaging several buildings, but thankfully leaving no human victims. Ten more such launches are planned by China in the coming years, as they assemble a new space station in Earth orbit. Their last space station also fell, uncontrolled, to Earth in 2018, landing safely in the Pacific Ocean, although again more by luck than judgement.

So far, then, they have been lucky. But it just seems irresponsible and wrong to take such risks. NASA is on record as saying, "It is clear that China is failing to meet responsible standards regarding their space debris", although the USA and Russia have also been guilty of losing control of their space garbage in the past. But China is definitely the worst repeat offender. One day, one of these re-entries is going to land on a city and kill thousands. 

We should not be allowing uncontrolled crashes, especially when we now have the technology to use re-usable rockets. Furthermore, the remains of these various space experiments are now littering our oceans, contaminated with hydrazine, a toxic rocket fuel.