Kaguya Moon Probe Impacts Surface
Click here for more news / Clique aqui para mais notícias
Kazuki Shiibashi/Tokyo
Japan's Kaguya moon probe smashed into the lunar surface as planned at 3:25 am JST June 11, concluding a 21-month mission that began with launch on an H-IIA rocket from Tanagashima Space Center on Sept. 14, 2007.
The satellite crashed at 1.6 kilometers per second (3,600 mph) at an angle of 10 degrees on the southeast quadrant of the near side of the moon, near the Gill Crater at 80.4 degrees east longitude and 65.5 degrees south latitude.
"Everything went exactly as planned thanks to the detailed observation/operation data acquired by Kaguya itself," Project Manager Susumu Sasaki said.
"I was delighted at the point of impact, but now a couple hours later it's beginning to sink in," Sasaki continued. "I've been with the project for 14 years and it's almost as though I've lost a son. But I am also relieved it went so well." The mission previously was led by Project Manager Yoshisada Takizawa, who moved on to other administrative responsibilities last year.
Also known as the SELenological and ENgineering Explorer, or Selene, the probe began lowering its altitude in February, dropping from its 100-kilometer (60-mile) science orbit down to 50 kilometers (30 miles) to spend two months measuring the moon's magnetic field. Then in April the spacecraft descended to 10-30 kilometers for detailed observations of the lunar south pole.
Finally, at 2:36 am JST June 10, half an orbit before impact, Selene performed a 140-second thruster burn around the north pole, creating a small reverse thrust of 2.5 meters per second and setting the next predicted perigee at four kilometers below the lunar surface to ensure a crash. Sasaki said attitude control went better than expected and Kaguya's Laser Altimeter managed to measure down to around 400 meters (1,300 feet) before loss of signal.
Sasaki believes the 2,600-kilogram (5,730-pound) satellite would have only created a small crater five to ten meters wide and about a meter deep, and it would have been difficult to spot the rising debris cloud from the Earth. However he has received unconfirmed reports that ground observations were made. He says what observers saw was most likely the 40 kilograms of remaining hydrazine fuel burning at the point of impact, rather than the impact itself.
After entering its final science orbit in December 2007, Kaguya spent 10 months in its formal observation phase, followed by 7.5 months of extended operations, creating global topographic, gravitational and magnetic maps of the moon. The Japan Aerospace Exploration Agency says it is preparing to release most of the mission data worldwide over the internet on Nov. 1, and hopes this will aid further scientific research and understanding of the moon for future space missions.
Selene was Japan's second lunar probe. India's first lunar orbiter, Chandrayaan, is in orbit now, and NASA's Lunar Reconnaissance Orbiter is set to blast off June 17. China's first lunar probe, Chang'e 1, was launched in 2007 and deorbited around the moon in March 2009.
Artist's concept: JAXA
