The Nikkei share average ended up 0.15 per cent at 23,124.95, while the broader Topix lost 0.23 per cent to 1,624.71.

The Nikkei average rose 3.1 per cent to close at 19,638.81, a peak unseen since March 10.

The Nikkei share average gained 0.5 per cent to 21,556.51, not far from its more than 10-week high.

The broader Topix was up 0.2 per cent at 1,632.20.

The broader Topix dropped 0.6 per cent to 1,732.90.

"Astronauts would ascend to 20 km by electrical elevator. From the top of the tower, space planes will launch in a single stage to orbit."

The vast globe would float at the surface of the sea, but could be submerged in bad weather, down the centre of a gigantic spiral structure.