Rocket Lab's Humanity Star is expected to reach a fiery doom much earlier than expected.

The 8kg carbon fibre geodesic sphere with 65 reflective panels, which resembled a disco ball, was shot into orbit from the Mahia Peninsula on January 21 on board Rocket Lab's Electron rocket.

The launch also carried small satellites into the Earth's orbit for US companies Planet Labs and Spire Global.

It was expected the Humanity Star would be one of the brightest objects in the night sky for nine months, but satellite-tracking website Satview reported on Wednesday that it will re-enter the Earth's atmosphere and disintegrate at 3am (NZT) on Friday.

Rocket Lab's own tracking of the sphere shows it is steadily dropping.

The Atlantic reported on Wednesday that the Humanity Star's amount of drag, due to its small size, would be the reason for its early descent.

"Things often perform differently in a space environment, which is what we discovered with the Humanity Star," Rocket Lab chief executive Peter Beck told The Atlantic.

Anything left of the sphere is likely to come down in the south Pacific Ocean.

Rocket Lab has been approached for comment.

In January, Mr Beck said on thehumanitystar.com that it was "born of the desire to encourage people to consider their place in the universe and reflect on what's important in their own lives and the lives of humanity as a species".

Some astronomers, however, described the Humanity Star as a shiny piece of space junk in an already crowded place.