After a week of speculation, China's Long March 5B rocket has fallen to Earth in the Indian Ocean. The location provided relief to those worried about debris landing on a populated area, and disappointment for those hoping for a spectacular light show as most of the rocket burned up on re-entry.
According to the Chinese Manned Space Engineering Office, the 30-meter (100-foot) long rocket re-entered the atmosphere at 11:24 pm ET May 8 (2:24 UTC May 9), at 72.47º east, 2.65º north, placing it around 300 kilometers southwest of Malé, the capital of the Maldives.
It is not yet known if the Chinese foreign ministry’s confident predictions most of the rocket would burn up in the atmosphere, leaving little debris to pose a threat, has come true. However, a boat would have to have been very unfortunate indeed to have been in exactly the right location to be hit by whatever did make it through the air.
Former satellites, rockets, and pieces of space junk come back to Earth frequently. However, those weighing less than 10 tons are considered safe, since they burn up in the atmosphere. Since 1990, heavier items have usually been brought down through controlled re-entries. In this case, however, Long March’s water landing was based on chance, rather than good management – although with 70 percent of Earth’s surface being ocean the odds were always good it would turn out this way.
At an estimated 22.5 tonnes, Long March is thought to be the eighth heaviest object to re-enter the atmosphere, and the equal fourth largest to make an uncontrolled entry. The largest partial re-entry, of the Skylab space station in 1979, landed in a sparsely inhabited part of Western Australia. The fears that aroused – or perhaps the highly publicized fine for littering the local council issued to NASA – inspired the adoption of safety protocols for large objects that has meant events like this one have been rare since.
The Long March rocket’s tumbling motion made it difficult to predict the timing of its re-entry point accurately. Nevertheless, with estimates on Friday putting the likely time at 11:23 pm ET (2:43 am UTC), and subsequent updates making an estimate of 3:02 am ±1 hour, calculations proved close to the mark.
However, the speed with which Long March 5b was traveling meant uncertainty of just a few minutes could see it arrive anywhere over a path thousands of kilometers long.
The Chinese space program faced considerable criticism after debris from a previous uncontrolled re-entry of a rocket did minor damage to villages in Cote d’Ivoire, and could easily have killed or injured people. It is unclear whether no action was taken to prevent a repeat, or if efforts were made that proved unsuccessful. The rocket was used to launch the first module of the Tiangong Space Station. With almost a dozen more launches planned over the next 18 months, we may need to get used to watching out for space debris.
