The Progress M-27M spacecraft is on its last orbits of Earth before it will be destroyed on re-entry into our atmosphere.
Exactly when and where that will happen is not known. But, if you are very lucky, you might get a chance to spot the doomed Russian spacecraft before it breaks up or even during its demise.
The unpiloted spacecraft was going to transport supplies to the International Space Station, but has been out of control since it entered orbit on Wednesday April 28.
What went wrong is still unclear, but since entering orbit it has been tumbling end-over-end every six seconds.
Initially Progress M-27M was in an orbit that took it between 193 and 278 kilometres above the Earth.
While this is above the bulk of the atmosphere, there is sufficient gas at this altitude to produce drag and lower the spacecraft’s orbit.
On Thursday May 7, Progress M-27M’s altitude was consistently below 190 kilometres altitude. It could re-enter the Earth’s atmosphere in the next day or so.
The Progress M-27M is on an orbit tilted relative to the equator, so it travels between latitudes of 52 degrees north and 52 degrees south (and back) during each orbit.
As the Earth spins underneath the orbiting spacecraft, it passes over different parts of the globe throughout the day as it orbits every 88 minutes. Its orbit takes it over Australia and New Zealand, London and southern England, the contiguous states of the US, and southern Canada.
Websites including Heavens-Above and N2YO provide estimates of when satellites will pass over your location. As the orbit of the spacecraft is rapidly decaying, it may arrive a little earlier than the times predicted by these websites.
If you are lucky, you will get a chance to spot Progress M-27M. It will look like a star moving across the sky, and it will get brighter and fainter every three seconds, as it tumbles through space.
At the time of writing, Progress M-27M was expected to re-enter the Earth’s atmosphere as soon as Friday May 8, although exactly when is uncertain by many hours.
The ABC quoted the Russian space agency estimating the spacecraft would “end its existence on May 8 between 1.23am and 9.55pm, Moscow time”. That would mean anytime between 8.13am AEST Friday May 8 and 7.55am AEST Saturday May 9.
As the spacecraft is moving at almost eight kilometres every second and the Earth spins on its axis every 24 hours, where the Progress M-27M will re-enter the Earth’s atmosphere is also very uncertain. Even an error of two minutes in the predicted re-entry time corresponds to almost 1,000 kilometres.
Odds are the re-entry will occur over the ocean or sparsely populated areas. But there is a chance that the re-entry will observable.
Last year hundreds of people across south-eastern Australia saw the re-entry of a Russian rocket.
As a spacecraft enters the Earth’s atmosphere at many kilometres per second, the exterior of the spacecraft will be heated to thousands of degrees Celsius and experience large aerodynamic forces.
As the Progress M-27M has no heat shield (and is tumbling out of control), this will result in the fiery destruction of the spacecraft.
Only some parts of the seven-tonne spacecraft will reach the surface of the Earth, and it is exceptionally unlikely they will harm people or damage property.
Many spacecraft re-enter the atmosphere each year without incident. Even when the 77-tonne Skylab space station re-entered over Western Australia in 1979, accompanied by loud sonic booms, it did not cause injuries or property damage.
So look up at the skies and you may see the doomed Progress M-27M spacecraft tumble through space. And who knows, you may be fortunate enough to see a multi-million-dollar fireworks show.