Long March 5-B uncontrolled re-entry

The Tianhe-1 is the first part of the new Chinese space station. If you like, it's an orbiting foundation, but more accurately, it's called a "core module".

At 16.6 metres in length and 22.6 tonnes, it's big already, but it'll grow as the Chinese Space Agency adds modules. It's got several docking ports to allow expansion as well as providing parking space for service vehicles.

It was launched on 29 April on top of a Long March 5B heavy-lift rocket.

The launch went well and the upper stage of the Long March rocket reached the planned orbit. After dropping the payload, it was probably meant to restart and slow down. This way it would fall back to Earth not far from the launch point.

This didn't happen, and the 21 tonne rocket remained in orbit, rising to over 240km, and then dipping to about 150km every 90 minutes. The rocket was also tumbling, indicating it wasn't under control. With each dip in altitude, the rocket brushed the upper atmosphere, slowing it down a little through friction.

Sooner or later, the rocket was going to re-enter and crash in a flaming rain of debris.

But where?

Of course, it's not the first time this has happened with a Long March 5B. Last May, one crashed into a village in the Cote d'Ivoire. Nobody was hurt, but there was some property damage. That was lucky.

As you may have heard, the rocket re-entered over the Arabian Peninsula and crashed into the Indian Ocean west of the Maldives. We haven't received any reports of damage.

We're not sure if the Chinese Space Agency intends to prevent this from happening again or not. While the Chinese acknowledged the rocket was going to make an uncontrolled re-entry, their only statement was that this is a common practice.

Kelvin Hennessy got a photo of the core module as it passed over Kingscliff in NSW on Saturday. This is a blend of 11 ten-second photos using a Canon 6D DSLR and a Sigma 8mm fisheye lens. Kelvin is showing once again that good planning helps you get great photos.