From laser beams and wooden satellites to galactic tow-truck services, start-ups in Japan are trying to imagine ways to deal with a growing environmental problem: space debris.

Junk like used satellites, parts of rockets and wreckage from collisions has been piling up since the space age began, with the problem accelerating in recent decades.

"We're entering an era when many satellites will be launched one after another. Space will become more and more crowded," said Miki Ito, general manager at Astroscale, a company dedicated to "space sustainability".

"There are simulations suggesting space won't be usable if we go on like this," she told AFP. "So we must improve the celestial environment before it's too late."

The European Space Agency (ESA) estimates that around one million pieces of debris larger than a centimeter—big enough to "disable a spacecraft"—are in Earth's orbit.

NASA has a provided a tantalizing teaser photo ahead of the highly-anticipated release next week of the first deep-space images from the James Webb Telescope—an instrument so powerful it can peer back into the origins of the universe.

The $10 billion observatory—launched in December last year and now orbiting the Sun a million miles (1.5 million kilometers) away from Earth—can look where no telescope has looked before thanks to its enormous primary mirror and instruments that focus on infrared, allowing it to peer through dust and gas.

The first fully formed pictures are set for release on July 12, but NASA provided an engineering test photo on Wednesday—the result of 72 exposures over 32 hours that shows a set of distant stars and galaxies.