Japan’s Venus Orbiter and Solar Sail Missions Launch Successfully

Japan’s first robotic mission to Venus and an experimental solar sail launched successfully from the Tanegashima Space Center in southern Japan. The Venus Climate Orbiter, or Akatsuki, the IKAROS solar sail and several smaller payloads launched aboard an H-IIA rocket at 6:58 local time May 21 (21:58 UTC May 20). The video shows a very smooth-looking launch, and 27 minutes later, JAXA confirmed the successful separation of Akatsuki. Then, about 15 minutes after that, the solar sail canister separated.
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Japan to Launch Venus Orbiter and Solar Sail Missions

IKAROS - solar sail from Japan. Image: JAXA

Bad weather postponed a scheduled multi-mission launch of an H-IIA rocket from Japan early Tuesday, which includes the first Japanese probe to Venus and an experimental solar sail. The next launch attempt for the “Akatsuki” Venus Climate Orbiter and the solar sail called IKAROS will be Thursday, May 20, at 21:58 UTC (May 20 at 5:58 EDT) – which is May 21 at 6:58 in Japan. Akatsuki is Japan’s first mission to Venus, and it will work closely with the ESA’s Venus Express, already at Venus. Also called Planet C, the box-shaped orbiter should arrive at Venus in December and observe the planet from an elliptical orbit, from a distance of between 300 and 80,000 kilometers (186 to 49,600 miles), looking for — among other things — signs of lightning and active volcanoes.

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Another payload is the solar sail, or “space yacht” IKAROS (Interplanetary Kite-craft Accelerated by Radiation of the Sun). This 320kg, 1.8m-wide, disc-shaped spacecraft will deploy an ultra-thin, ultra-light, 14 meter sail that will propel the structure from the radiation pressure from sunlight hitting it.

“The purpose of IKAROS is to demonstrate the technology of the Solar Power Sail,” said Osamu Mori, project leader of IKAROS. “Simply put, the solar sail is a ‘space yacht.’ A yacht moves forward on water, pushed by wind captured in its sails. A solar sail is propelled by sunlight instead of wind, so it’s a dream spaceship – it doesn’t require an engine or fuel. Part of IKAROS’s sail is covered by a solar cell made of an ultra-thin film, which generates electricity from sunlight.”

So far, solar sails have only been tested, but never flown successfully. It is hoped IKAROS will be the world’s first solar-powered sail, and that the structure will sail towards Venus, following Akatsuki.

The experimental sail is thinner than a human hair, is also equipped with thin-film solar cells to generate electricity, creating what JAXA calls “a hybrid technology of electricity and pressure.”

To control the path of IKAROS, engineers will change the angle at which sunlight particles bounce off the sail.

Akatsuki and IKAROS on the launch pad Taken on May 17, 2010, about 24 hours before the planned launch of Akatsuki and IKAROS toward Venus. They are stacked aboard an H-IIA rocket. Credit: Mitsubishi Heavy Industries, Ltd.

If you are a member of The Planetary Society, your name will be heading to Venus on both Akatsuki and IKAROS. The Planetary Society, a long-time proponent of solar sail technology, and Japan’s space exploration center, JSPEC/JAXA, have an agreement to collaborate and cooperate on public outreach and on technical information and results from IKAROS, which will help TPS plan for its upcoming launch of its own solar sail vehicle, LightSail-1, which they hope to launch in early 2011.

Emily Lakdawalla at the Planetary Blog has more details about the two missions and TPS’s involvement.

The H-IIA will also carry four other small satellites, developed by Japanese universities and other institutions. They include:

The 2-pound Negai CubeSat, developed by Soka University of Japan. Negai will test an information processing system during a three-week mission.

The WASEDA-SAT2, developed by Waseda University. The 2.6-pound spacecraft will conduct technology experiments in orbit.

The 3.3-pound KSAT spacecraft developed by Kagoshima University will conduct Earth observation experiments.

The 46-pound UNITEC-1 satellite from the Japanese University Space Engineering Consortium will test computer technologies and broadcast radio waves from deep space for decoding by amateur radio operators.

The rocket will launch from Japan’s Tanegashima Space Center in southern Japan.

For more information on IKAROS, read this interview with the project leader, Osamu Mori

Hard-Luck Hayabusa In More Trouble

Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA

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A problem-plagued Japanese mission to an asteroid just may have received its final blow. The Haybusa mission, which went to asteroid Itokawa in 2005 is currently trying to return to Earth, but now has suffered a breakdown in the third out of four ion thrusters. The cause was a voltage spike due to problems with a neutralization vessel, which previously caused the failure of two other thrusters. The fourth and only remaining thruster was shutdown earlier by engineers after signs that it also might succumb to high voltage damage. Engineers are now testing that engine, Thruster C, to determine if it is capable of long-duration firings. Hayabusa, which landed on Itokawa (possibly several times – mission managers aren’t sure) might contain samples, but due to a malfunction of the sample collection device, JAXA has acknowledged that it cannot be sure Hayabusa actually managed to take samples from the surface of the asteroid.

Thruster D failed last Wednesday, according to the Japan Aerospace Exploration Agency (JAXA).

Hayabusa’s four experimental microwave discharge ion engines consume xenon gas and expel the ionized propellant at high speeds to produce thrust. Ion engines are more efficient than conventional chemical thrusters because they use less fuel and can operate continuously for thousands of hours. Hayabusa’s thrusters have accumulated almost 40,000 hours of burn time since the probe launched in May 2003.

The spacecraft was originally scheduled to return to Earth in 2007, but the arrival date was pushed back to 2010 following thruster, communications, gyro and fuel-leak problems.

Thruster D had been the lone engine guiding the spacecraft since February 2009. Officials now say they are evaluating the asteroid mission’s return course after last week’s glitch, and will try to re-fire Thruster C in order to obtain the trajectory and speed required for the return to Earth.

Hayabusa spent three months exploring Itokawa in late 2005, taking over 1,600 pictures and collecting near-infrared and X-ray spectral data to investigate the small potato-shaped asteroid’s surface composition.

During a failed sampling attempt in November 2005, Hayabusa made an unplanned landing and spent up to a half-hour on Itokawa, becoming the first spacecraft to take off from an asteroid. The spacecraft attempted to fire a pellet into the asteroid’s surface and retrieve rock samples through a funnel leading to a collection chamber. However, telemetry showed Hayabusa likely did not fire its projectile while on the surface; but scientists were hopeful bits of dust or pebbles found their way through the funnel and into the sample retrieval system.

Source: Spaceflightnow