Uncontrolled reentry of Chinese rocket expected tomorrow, 5/8/21

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Frequently in a space launch one of the stages in the rocket is so massive that it will not completely burn up when it reenters the atmosphere. The normal, responsible behavior is to have a controlled burn after the payload is launched which will push the rocket stage into a calculated reentry. This allows the rocket owner to pick the place on the planet the residuals will land, say the middle of an ocean far from routine shipping channels.

The irresponsible strategy is skip the reentry burn which means the massive chunks of unburned metal will land on the earth at some random place, say an occupied area or even a major city.

This information from Space News on 4/30/21: Huge rocket looks set for uncontrolled reentry following Chinese space station launch.

The Chinese Long March 5B uses a distinct configuration, consisting of four sides boosters and the core rocket. The sides boosters do not reach orbit and therefore fall to earth in a calculable position. Those can be controlled to land in a safe place. The core, however, does reach orbit and therefore will eventually come back to earth.

US military radars and one private tracker (apparently there are people who track satellites as a hobby!) Have detected that the Long March 5B launched this week (4/28/20) has not done a deorbit burn and is currently tumbling in space on a very slowly deteriorating orbit. That means it will reenter the atmosphere and land on the planet at some indeterminate location.

This is also how China handled the first launch of the Long March 5B. It made an uncontrolled reentry, landing in the Atlantic Ocean, missing an unscheduled landing in the United States by only 15 or 30 minutes.

Article says the Tiangong-1 space station made an uncontrolled reentry back in 2008 but the Tiangong-2 was pulled back to earth (deorbited) with a controlled burn.

5/7/21 – Washington Examiner – China’s space debris: What we know so far – The core rocket of China’s Long March 5B will have an uncontrolled reentry to the atmosphere. Expectation is it will hit the planet on Saturday, 5/8/21.

A large portion of the rocket will be burned up but the expectation is big chunks will reach the surface.

Where will it hit the planet? Completely unknown.

The reason is this is an uncontrolled reentry. In other words China did not design the rocket to have the capacity to deorbit at a place and time of its choosing, thus it will fall in a random path based on the laws of physics and the interaction of many uncontrolled variables.

Apparently, since 1990 everything launched into orbit has been designed to have a controlled deorbit of all parts over 10 tons. Nothing larger than that has had an uncontrolled reentry in the last 30 years. Except for Chinese launches.

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