China’s Long March-5 booster departs Wenchang launch site.
Credit: CASC

China’s incoming Long March 5 booster core stage is generating lots of speculation – particularly the when, what, and where leftovers might reach the Earth’s surface.

Here are a few down-to-earth factoids provided to Inside Outer Space from T.S. Kelso of CelesTrak, an analytical group that keeps an observant eye on Earth-orbiting objects:

  • The CZ-5B core stage is supposed to be around 21 metric tons. That’s about twice the mass of an average school bus or the empty mass of a Boeing 737. Estimates for objects like this are that 20-40% of the mass might survive reentry to the surface.
  • The rocket body is in a 41° inclination orbit and the uncertainty being given by the 18th Space Control Squadron that predicts when and where human-made objects will reenter the Earth’s atmosphere is ±900 minutes (15 hours). That’s somewhere between 10 orbits before and after the predicted reentry point (May 9 at 04:25 UTC/00:25 EDT). Essentially, that means it could come down anywhere between 41° N and 41° S latitude.
  • Perigee (the lowest point of the orbit) is over the Southern Hemisphere and reentry is expected to occur around perigee, so the reality is that observers in Southern Africa, South America, or Australia might see the reentry—not observers in North America or Europe. But most of the Earth is covered by water and much of those land areas are sparsely populated, so it is more likely to pass without anyone actually seeing. In fact, a Long March-3B rocket body just reentered on May 3 and seems to have gone virtually unnoticed—on the equator in the middle of the Pacific Ocean.
  • The likelihood of anyone being injured by this type of event is small but would not be inconsequential if it happened. Yet we have over 2,000 other uncontrolled rocket bodies still in Earth orbit and each of them presents a risk to people on the surface or satellites in orbit.
  • We need to be more responsible and stop leaving these objects in orbit after they have completed their job of deploying their satellite(s) to their intended orbits.

The Aerospace Corporation’s Center for Orbital and Reentry Debris Studies is monitoring the rocket stage (ID 48275).
Artwork: The Aerospace Corporation/CORDS





For follow-up reading, go to:

A Space Debris Expert Weighs in on the Massive Chinese Rocket Body Falling Uncontrollably to Earth at:

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