© South China Morning Post
Lena Okajima, chief executive of space technology venture ALE.
Fancy a meteor shower racing across the night sky to mark your birthday? One Japanese start-up is hoping to deliver shooting stars on demand and choreograph the cosmos.

And, say scientists, it's not just about painting huge pictures on the night-sky that would be visible to millions of people; artificial meteors could help us to understand a lot more about Earth's atmosphere.

Lena Okajima, who holds a doctorate in astronomy, says her company, ALE, is intending to launch a micro satellite that can eject shooting stars at exactly the right time and place to put on a celestial show. "I'm thinking of streams of meteors that are rare in nature," Okajima said in an interview. "It is artificial but I want to make really beautiful ones that can impress viewers."

In collaboration with scientists and engineers at Japanese universities, the ALE team is developing a satellite that will orbit the Earth and eject dozens of balls, a few centimetres in diameter, at a time.

These balls - whose chemical formula is a closely guarded secret - will race through the atmosphere at around 7-8km a second, glowing brightly from the friction as they burn up in the atmosphere.

Although it sounds fast, that is considerably slower than naturally occurring meteors which can hurtle through the atmosphere at up to 80km a second.

Tinkering with the ingredients should mean that it is possible to change the colour of each bright streak, says Okajima, offering the possibility of a multi-coloured shower of shooting stars. The stars are expected to shine for several seconds before they are completely burned up - well before they fall low enough to pose any danger to anything on Earth.

"People may eventually become tired of seeing shooting stars if they come alone. But they could be coupled with events on the ground," Okajima said.

"Making the sky a screen is this project's biggest attraction as entertainment. It's a space display."

Beautiful it might be, but it won't come cheap; each shooting star would cost around a million yen (HK$63,000), as the company tries to make back the more than 1 billion yen price tag for the development and launch of each micro satellite.

Each satellite, currently at the design stage, would be a 50-centimetre cube orbiting the Earth at an altitude of around 400-500km. Each would only have a limited lifespan, says aerospace engineer Takeo Watanabe of Teikyo University, explaining that after a few months they will fall and burn up in their own blaze of light.

Source: Agence France-Presse