The rocket was sent to space to carry a module for China’s new space station, but unexpectedly reached orbital velocity and is now circling the planet once every 90 minutes.
The United States Space Force is now tracking the rocket, which is expected to crash within the week – between 8 and 10 May 2021.
The 30-metre long rocket passes by just north of New York, Madrid, and Beijing, and as far south as Chile and New Zealand, giving scientists some notion of its potential target.
There are fears that the rocket could land on an inhabited area, the“equivalent of a small plane crash scattered over 100 miles”. Another Long March rocket fell in May 2020, with debris reported in villages in the Ivory Coast.
“The Long March 5B core stage is seven times more massive than the Falcon 9 second stage that caused a lot of press attention a few weeks ago when it re-entered above Seattle and dumped a couple of pressure tanks on Washington state,” Jonathan McDowell, Astrophysicist at the Astrophysics Center at Harvard University said.
“I think by current standards it’s unacceptable to let it re-enter uncontrolled. Since 1990, nothing over 10 tons has been deliberately left in orbit to re-enter uncontrolled.”
Atmospheric density also makes the rocket’s descent difficult to predict. Spacecraft do not typically fly below 300 kilometres, so scientists’ knowledge of the physics is relatively limited.
The rocket’s speed makes it hard to predict where it will fall, but space agencies have some notion of its parameters.
Since CZ-5B’s orbit (the classification for the debris) is inclined at 41 degrees to the Earth’s axis, any debris will not fall further than that either north or south of the latitude. In Europe, that includes Spain, Italy, and Greece, according to the European Space Agency.
Fortunately, it is unlikely that the rocket’s descent will do serious damage. The “worst case [scenario] is one of the structural rods hits someone, potentially a fatality but unlikely to see multiple casualties”, McDowell told The Independent.
There could be expensive property damage because of the speed of the debris, but the spread of the craft’s disintegration means only one or two pieces are likely to hit a populated area.
It is likely that most of the rocket will burn up on re-entry and, because the Earth is 75 per cent water, fall into the ocean.