Japan launched its newest flagship-class environmental satellite Jan. 24 on a three- to five-year mission that experts here said could breathe new life into a civilian Earth observation program that has been plagued by delays and failures over the last decade.
The Advanced Land Observing Satellite lifted off from southern Japan’s Tanegashima space center aboard an H-2A rocket and was placed into a near-polar orbit with an altitude of approximately 700 kilometers, according to the Japan Aerospace Exploration Agency (JAXA). Now called Daichi, the satellite successfully deployed its 22-meter solar paddle and data relay antenna in the hours and days following the launch, JAXA said.
In a statement issued after the launch, Japanese Prime Minister Junichiro Koizumi, hailed it as more evidence of steady progress in Japan’s space program.
Masakazu Iguchi, chairman of Japan’s Space Activities Commission, said in a statement that the launch helped validate recent improvements to the H-2A rocket. This was the second successful H-2A launch since a November 2003 failure that destroyed a pair of national security imaging satellites.
The Daichi satellite, built by NEC Toshiba Space Systems of Tokyo at a cost of 53.5 billion yen ($464 million), weighs 3.7 tons and is capable of generating 7 kilowatts of power. It carries three main sensors: an optical imager for 3D stereoscopic mapping; an advanced sounder for characterizing land cover; and a synthetic aperture radar for all-weather, day-night mapping.
“All-in-all it’s a very valuable satellite for Japan’s satellite imagery program and an opportunity to provide a complete suite of data,” said Robert R. Clemons, a remote sensing expert with Gatling Associates, a Tokyo-based defense and technology consulting firm. “Given that it operates as designed it will re-establish the excellence of Japan’s technology and [the nation] as one of the leading players in the world of open-use … satellites.”
Daichi is Japan’s first purely civilian Earth observation satellite to be launched since Adeos-2, which failed in October 2003, just 10 months after being launched. Adeos-1 failed in June 1997, also 10 months after being launched.
Adeos-1 and Adeos-2 were designed primarily to study the atmosphere and oceans. Daichi, by contrast, is decidedly terrain-focused.
Yoshiyuki Chihara, director of the Office of Space Utilization and Promotion in Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT), said Daichi’s primary missions are to make 1/25,000-scale maps of Japanese territory and contribute to global disaster-monitoring efforts. The satellite’s Panchromatic Remote Sensing Instrument for Stereo Mapping, or Prism, has three cameras that can cover wide swaths of territory at 2.5-meter resolution, he said.
“Prism has three eyes, one looking forwards, one looking [directly downward] and one looking backwards. Normally optical sensors only have one eye, and the usual case is that to have high resolution, you have a shortened field of observation, but with Prism you have relatively high resolution with a wide, 70-kilometer field of vision,” Chihara said.
The satellite’s Phased Array L-band Synthetic Aperture Radar, designed to detect changes in topography and geology, will operate in four frequencies so that it will be able to make highly detailed observations, Chihara said. JAXA reported Jan. 26 that the radar antenna had deployed successfully.
The Advanced Visible and Near Infrared Radiometer-2, for observing vegetation and land-use changes, is an advanced version of sensor that flew on the Adeos 1 satellite , according to Yukinori Nakajima, a staffer within MEXT’s Office for Space Utilization and Promotion. But the newer sensor will have better resolution than its predecessor, he said.
The Daichi satellite also boasts more data storage capacity and higher transmission rates than the Adeos craft, Chihara said.
The launch of Daichi took place after several days of delay due to technical issues with the H-2A rocket and poor weather conditions near the launch site. The satellite originally was supposed to launch in 2001, but fell behind schedule due to JAXA budget instability and technical problems with other satellites.
For example, problems in 1997 with the reaction-wheel attitude control system aboard the ETS-7 automatic rendezvous and docking satellite prompted JAXA to change out similar hardware aboard the Daichi platform, Nakajima said.
The Adeos-2 failure led JAXA officials to redesign the bundle of cables that distribute power from Daichi’s solar paddle to its components, Nakajima said.
Despite the fact that the satellite’s design is old, and that its original focus was technology demonstration rather than applied science, a successful Daichi mission should “revitalize” JAXA’s Earth observation activities, Kazuto Suzuki, professor of international politics and economics at Japan’s Tsukuba University, said via e-mail Jan. 16.
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