Planetary News

May 22, 2004

Hayabusa Succeeds in Earth Swingby to Reach Asteroid Itokawa next June

Artist's depiction of Hayabusa nearing Asteroid Itokawa Image: JAXA/ISAS

Hayabusa, the world's first spacecraft to bring back home sample material of an asteroid, swung by the Earth at 3:22p.m. May 19, 2004, Japan Standard Time. Hayabusa swept away at the closest altitude of 3700km from the surface of our planet, completing the navigation manuever to place itself into a new trajectory toward Asteroid Itokawa.. Hayabusa is the first spacecraft which performed successfully the combination of ion engines acceleration and Earth swingby.

Formerly known as Muses-C, Hayabusa was launched on May 9, 2003 aboard the Mu-V rocket. The spacecraft swung out into a wider orbit around the Earth to continue flight by using four onboard ion engines. According to ISAS, the division responsible for scientific robotic missions of JAXA, the asteroid explorer is functioning smoothly after its historic trajectory manuever.

Mission staff jubilant with Hayabusa's successful Earth swingby on May 19 Image: JAXA/ISAS

Itokawa, a tiny celestial body of 500 meters in diameter with designation of Asteroid 1998SF36, was named as such last July after the late Dr.Hideo Itokawa, the father of rocket development of Japan. The irregularly shaped asteroid is circling around the sun at a distance of about 300 million km from Earth.

Hayabusa's main body is a box of 1.5 x 1.5 x 1.2 meters, weighing about 510kg in net mass. After its rendezvous with the asteroid Itokawa in June 2005, the robotic asteroid probe will conduct a five-month-long scientific survey from the orbit before it begins plunging down toward the target in an attempt to collect sample material from the asteroidal surface. As landmarks for sample collection, Hayabusa will release three softball sized target markers. They are painted with luminous agents, generating flash light against laser beams released from the spacecraft. Then the spacecraft will start to descend and fire a small iron ball three times, collecting ejected material from the surface of the asteroid by using a horn-like sampler. About a gram of sample materials will be collected by three one-second touch and go contacts. Collected samples will be stored tight within an onboard re-entry capsule.

Upon completing sample collection sometime in November 2005, Hayabusa will bid farewell to Asteroid Itokawa and coast around in space until it arrives at Earth's upper atmosphere in July 2007. Then the re-entry capsule will be detached from the spacecraft. After having sped through the atmosphere, the re-entry capsule continues descent by deploying the parachute. Its landing site is a desert located near the southern town of Woomera in Australia.

Earth receding into the distance of approx. 95,000km at 8:10p.m. May 19, JST Image: JAXA/ISAS

Hayabusa acquired a number of images of Earth and the Moon along the way to its perigee to Earth. This image of Earth was captured at 8:10p.m. on May 19(JST).The distance between the spacecraft and the earth was about 95,000km. Now, 877,490 names are on the sure way to get to the asteroid Itokawa. The names were printed on the specially processed aluminum foil sheet to be enveloped inside one of the three target markers. They will be released down on the surface of Asteroid Itokawa, their permanent cradle in space.