《USGS Release: Landsat 5 Experiences Malfunction 》

  • 来源专题:湿地遥感信息动态监测
  • 编译者: shengchunlei
  • 发布时间:2016-03-25
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    Landsat 5 Experiences Malfunction (Updated)Released: 8/24/2009 11:28:24 AM

    Contact Information:U.S. Department of the Interior, U.S. Geological Survey Office of Communication 119 National Center Reston, VA 20192.

    Kristi Kline Phone: 605-594-2585 Ron Beck Phone: 605-594-6550 .


    Update, 8/17/2009. Landsat 5 tumbled out of control in the early morning of August 13. Full operational capabilities restored. The cause of the malfunction is still being investigated.

    Satellite is Now Stabilized and the Cause is Being Investigated

    Landsat 5 tumbled out of control and power was at a critical level in the early morning of August 13.

    The cause for this anomaly is currently unknown and being investigated.

    The spacecraft has been stabilized after the USGS Landsat Flight Operations Team initiated recovery operations. Power is still at a critical level, and the extent of damage is yet to be determined. Imaging operations are suspended until further notice.

    “Landsat 5 has proven to be a remarkable success and has given the science community important information on land features of the planet,” said USGS Landsat Program manager Kristi Kline. “It was launched in 1984 and designed to last 3 years with a possible extension to five years. Incredibly it is still a valuable resource and by early 2009, it had completed over 129,000 orbits and acquired over 700,000 individual scenes.”

    Landsat 5 provided data demonstrating alterations over Chernobyl region after the nuclear power plant eruption, de-forestation of tropical rain forests, drought and flooding in the Mississippi River basin, construction of the Three Gorges dam in China, shrinking of the Aral Sea, Northern Wisconsin after a tornado pass, the impact of Hurricanes Katrina and Rita, and countless forest and wildfire outbreaks.

    For more information about Landsat 5 and others in the Landsat series, visit the Landsat Missions Web site.

  • 《USGS Release: Aging Landsat 5 Changes Glasses 》

    • 来源专题:湿地遥感信息动态监测
    • 编译者:shengchunlei
    • 发布时间:2016-03-15
    • Landsat 5 has orbited Earth over 150,000 times since it was launched in 1984, making it the longest-operating Earth observing satellite of its kind. During this time, two data collection instruments onboard Landsat 5 — the thematic mapper (TM) and the multi-spectral scanner (MSS) — have transmitted over five million images of land conditions to U.S. and international ground stations. In November 2011 an electronic malfunction in the TM transmitter forced a suspension of routine imaging. Now, after months of trying without success to restore daily TM image transmissions, USGS flight engineers will attempt only a few additional image acquisitions over specific sensor-calibration sites as the TM transmitter nears complete failure. On a positive note, the MSS instrument onboard Landsat 5 was recently powered back on in a test mode after more than a decade of silence. "The resurrection of the MSS a decade after it was last powered up and 25 years beyond its nominal lifespan is welcome news indeed," said USGS Director Marcia McNutt. "While not a complete replacement for the loss of the Thematic Mapper, it does provide some insurance for ensuring Landsat data continuity should Landsat 7 fail prior to Landsat 8 achieving orbit next year." The MSS sensor, the forerunner of TM, gathers data in fewer spectral bands than TM, has lower pixel resolution, and does not acquire thermal data. However, each MSS scene covers the same area as a TM scene, approximately 12,000 square miles. The USGS is currently acquiring MSS data only over the United States. Landsat International Cooperator stations may begin downlinking data from other parts of the globe, depending on their intentions and ability to establish MSS data processing capabilities. It will take some months for MSS data to be integrated into current production systems and be made publically available. Landsat 5 has sufficient fuel to operate through 2013. Landsat 7, the other active Landsat spacecraft operated by the USGS, continues to collect images worldwide, as it has done since 1999. In 2003, Landsat 7 experienced a hardware failure that causes a 22% loss of data in every image. In the intervening nine years, many techniques have been developed to partially compensate for the data loss and leverage the remaining data for scientific analysis and resource monitoring. The next Landsat, the Landsat Data Continuity Mission (LDCM or Landsat 8), is scheduled for launch in January 2013. Following launch, it will become Landsat 8 and is expected to extend the Landsat record for at least another five years. Once Landsat 8 is fully operational, the collection of MMS data from Landsat 5 will be re-evaluated. For further details and the latest information about the status of Landsat 5, visit the USGS Landsat Missions website. The Landsat Program is a series of Earth observing satellite missions jointly managed by the U.S. Geological Survey and NASA. Landsat satellites have been consistently gathering data about our planet since 1972. They continue to improve and expand this unparalleled record of Earth's changing landscapes for the benefit of all. USGS provides science for a changing world. Visit USGS.gov, and follow us on Twitter @USGS and our other social media channels. Subscribe to our news releases via e-mail, RSS or Twitter.
  • 《USGS Release: Landsat 5 Mission in Jeopardy 》

    • 来源专题:湿地遥感信息动态监测
    • 编译者:shengchunlei
    • 发布时间:2016-03-25
    • The U.S. Geological Survey (USGS) has stopped acquiring images from the 27-year-old Landsat 5 Earth observation satellite due to a rapidly degrading electronic component. Landsat 5 was launched in 1984 and designed to last 3 years. The USGS assumed operation of Landsat 5 in 2001 and managed to bring the aging satellite back from the brink of total failure on several occasions following the malfunction of key subsystems. There is now an increasing likelihood that the Landsat 5 mission is nearing its end. “This anticipated decline of Landsat 5 provides confirmation of the importance of the timely launch of the next Landsat mission and the need for an operational and reliable National Land Imaging System,” stated Anne Castle, Assistant Secretary for Water and Science at the U.S. Department of the Interior. “The USGS is committed to maintaining the unique long term imaging database that the Landsat program provides.” For several months, the Landsat flight operations team has been closely tracking the fluctuating performance of an amplifier essential for transmitting land-surface images from the Landsat 5 satellite to ground receiving stations in the U.S. and around the world. Over the past 10 days, problems with the amplifier have led to drastically reduced image download capabilities, a sign of impending failure. Numerous engineering and technical adjustments have been made to Landsat 5 in the past several days to sustain at least a limited imaging capability, but performance has continued to decline. Instead of continuing to operate until the amplifier fails completely, which could bring the mission to an end, USGS engineers have suspended imaging activities for an initial period of 90 days in order to explore every possible option for restoring satellite-to-ground image transmissions. The USGS-operated Landsat 7 remains in orbit collecting global imagery. Since its launch in 1999 with a 5-year design life, Landsat 7 has experienced an instrument anomaly which reduces the amount of data collected per image. Landsat 8, currently called the Landsat Data Continuity Mission, is now scheduled to be launched in January 2013. For further details and the latest information about the status of Landsat 5, visit the USGS Landsat Missions website. USGS provides science for a changing world. Visit USGS.gov, and follow us on Twitter @USGS and our other social media channels. Subscribe to our news releases via e-mail, RSS or Twitter. Links and contacts within this release are valid at the time of publication.