Japanese Earth Observing Satellite Begins Mission
The Advanced Land Observing Satellite 'Daichi' launched atop an H-2A rocket in a space shot staged by the Japan Aerospace Exploration Agency on Jan. 23, 2006.
Credit: JAXA.

A first-class, four-ton Earth remote sensing satellite was orbited by Japan Monday, setting off on a mission to help cartographers create more precise maps on a global scale, scientists in their search for natural resources and officials in response to disasters.

The Advanced Land Observation Satellite was launched into space by an H-2A rocket that came to life with a thunderous roar before climbing into cloud-filled skies above the Yoshinobu complex on Tanegashima Island in the southern part of Japan. Liftoff of the 174-foot tall booster was on time at 0133 GMT (8:33 p.m. EST Monday), or in the mid-morning hours at the launch site.

Fitted with two large solid rocket boosters and a pair of smaller strap-on motors, the H-2A launcher quickly sped away from Tanegashima on a southerly ground track. After a flight of 16 minutes and 30 seconds, the H-2A second stage deployed ALOS into the planned Sun-synchronous orbit with an altitude of around 430 miles above Indonesia's eastern islands.

On-board cameras provided stunning video of the four strap-on boosters separating from the rocket's main stage, and later the second stage releasing the ALOS spacecraft.

For the first time, the rocket's main stage LE-7A cryogenic engine sported an extended cooling nozzle that increases both thrust and efficiency to loft larger payloads. Insulation was also added to the nozzle to test the material before it is incorporated into more powerful versions of the country's leading launcher in the near future.

Five minutes after spacecraft separation, ALOS began to unfurl its 72-foot solar array -- the largest in Japanese space history -- that will provide electrical power to the craft throughout its mission. Six cameras are on-board to visually verify the correct deployment of the solar panel and various instrument antennas.

Today's flight had been postponed since last summer after engineers discovered transistors on another satellite being readied to launch contained foreign object debris, causing the units to work improperly. Officials checked a host of other satellites still on the ground for similar problems, and they noted that ALOS relied on similar transistors produced by the same company near the same time as those aboard the ASTRO-F infrared telescope. As a precaution, workers replaced the transistors on ALOS, delaying the launch until early this year.

A subsequent issue cropped up Wednesday concerning one of three telemetry transmitters on the H-2A rocket, and managers ordered a swap out of the suspect component. The vehicle was rolled to the pad from its nearby assembly hangar late Sunday, local time, in the final hours before a Monday morning launch attempt. However, Monday's try was scrubbed before sunrise to allow engineers time to troubleshoot an issue with ground equipment responsible for monitoring conditions inside the ultra-clean payload shroud.

Keeping with Japanese space tradition, ALOS carries a nickname -- "Daichi," which translates to "land" in English.

The craft is a key member of Japan's Earth observation fleet, and is one of the largest satellites ever sent into space in that nation's history. Weighing in at well over 8,000 pounds at launch, ALOS is designed to operate for at least three years, with a program objective for a mission lasting up to five years.

Japan's environmental satellite program has a past dotted with missions having premature endings, including the loss of two spacecraft tasked with tracking global warming and climate change.

Officials hope to put that karma to rest with ALOS, which will alone obtain data to compose worldwide maps on a 25,000 to 1 scale, but with special emphasis on the Asia-Pacific region. The satellite will use technology and instruments derived from those included on earlier missions such as the Japan Earth Resources Satellite and the Advanced Earth Observation Satellite project.

The Panchromatic Remote-sensing Instrument of Stereo Mapping, or PRISM, payload will take images with a resolution as high as eight feet in black-and-white. The optical camera consists of three sensors pointing forward, down, and backward along the craft's ground track as it orbits Earth. This feature allows the instrument to gather quality three-dimensional data in individual swaths over 20 miles wide for scientists and map-makers to use in their topographic maps.

Also aboard ALOS is the Advanced Visible and Near Infrared Radiometer-2 (AVNIR-2), which is derived from its namesake that flew on the ADEOS satellite in 1996. The device can pan across the flight path of the spacecraft at angles of up to 44 degrees, and will use this ability to help sense vegetation and plant types. This information will be compiled into land usage maps.

The third instrument included on the satellite is the Phased Array L-band Synthetic Aperture Radar, or PALSAR. This payload is an upgrade of a similar radar system that was aboard the JERS-1 platform that was launched in 1992. PALSAR will send radar beams toward Earth from space, and will analyze the pulses as they are bounced off the surface back to a receiver. This capability enables all-weather observations that can conducted around the clock.

Fully developed by the Japanese Aerospace Exploration Agency, ALOS is expected to contribute to response efforts during natural disasters and other emergencies due to the satellite's ability to produce detailed images within two days of an event. Regional observations will focus on land usage, crops, forests, and floating ice.

The next H-2A launch is just under a month away on February 15, when the multi-functional MTSAT-2 satellite will be launched on a dual mission to improve air traffic congestion in the Far East and to deliver regional weather data to forecasters. That flight will use the same model of the H-2A rocket as ALOS, and both vehicles were integrated in parallel using two mobile launch tables.

Other H-2A missions on the books in the coming year include the launch of a pair of Japanese government spy satellites by next March. The manifest also includes the oft-delayed mission to carry the ETS-8 communications and engineering test satellite to space.

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