Japanese solar-sailing space probe ready for take-off

The Ikaros probe will be launched on 18 May

The Japan Aerospace Exploration Agency is getting ready to launch the first spacecraft to use the Sun's power directly for a flight to Venus.

The Interplanetary Kite-craft Accelerated by Radiation Of the Sun (Ikaros) probe will be launched on 18 May, along with a second climate satellite destined for Mars by more conventional means.

Once in orbit Ikaros will deploy a solar sail stretching 20 metres across to gather the radiation of charged particles from the Sun.

The sail, which at 0.0075mm thick is thinner than a human hair, is studded with solar cells and control surfaces that the mission controllers hope will allow the spacecraft to be steered towards Venus.

As long as the Sun is hitting the sail the spacecraft gathers speed, and the direction of travel can be changed by tilting the sail.

"If it goes well it'll be an outstanding accomplishment," Dr Louis Friedman, executive director of the Planetary Society, told V3.co.uk.

The Planetary Society has been sharing information with the Japanese about solar sailing, he said, although the Ikaros probe is testing a different approach to solar sailing. "We're all trying to get solar sailing to fly," said Dr Friedman.

The Japanese goal is to combine solar sail propulsion with solar power to run an ion drive to boost speed in a probe going to Jupiter in by 2020.

The 300kg Ikaros probe is intended to test the solar propulsion and navigation technology with a six-month mission to head towards Venus, and carries monitoring equipment to measure dust levels and gamma radiation.

The Planetary Society's method is closer to pure solar sailing, and concentrates on developing as much speed as possible.

The LightSail 1 project, to be launched early next year, will use the power of the Sun to power a 5kg craft, compared to the 300kg Ikaros probe, with a long-term view to sending similar robotic probes over interstellar distances.

Solar sailing has, however, been plagued by bad luck. Cosmos 1, the Planetary Society's first solar sailing mission, was lost in a rocket accident, and a second craft was lost when PayPal founder Elon Musk's Falcon 1 rocket failed mid-flight.