Landsat 7 is a cooperative effort between 2 government agencies and is associated with both the Earth Observing System and the Mission to Planet Earth. NASA is responsible for designing, building, and testing both the spacecraft and ground systems, as well as launching the satellite. Another pre-launch task of NASA's is the development of all mission operations concepts, plans, and procedures. USGS will be responsible for the capture, processing, archiving, assessment, and distribution of all collected science data. USGS facilities at the EROS Data Center (EDC) will be used for these functions. In addition, USGS will assume responsibility for all program operations and will perform an overall mission management function.

The spacecraft will be operated from the Mission Operations Center (MOC) located at Goddard Space Flight Center. Functions that will take place within the MOC include planning and scheduling, health and safety telemetry processing and analysis, spacecraft command and control, spacecraft subsystem trending, anomaly isolation, investigation, and resolution, and sustaining engineering. Unlike many past missions, functions such as orbital planning aid generation and orbit determination and maintenace will be contained within the MOC. These functions will be provided by the Flight Dynamics Division by locating a commercial software application known as Satellite Tool Kit on a workstation in the MOC. The MOC is staffed by the Flight Operations Team (FOT) which is comprised of console anlysts, mission planners, subsystem engineers, and supervisor/manager functions.

Ground sites are planned for Sioux Falls SD, Fairbanks AK, Wallops VA, and Svalbard Norway (shown in the picture on the right, currently under constuction). Nominally, houskeeping data will be captured onboard and downlinked to the Sioux Falls and Alaska sites. Real-time housekeeping telemetry will be downlinked (and a command link established) whenever the spacecraft is in contact with the ground, no matter what the purpose of the contact is (payload data dump, housekeeping data dump, Doppler/tracking data collection, etc.). Stored housekeeping data is downlinked to the ground site and sent to the MOC in real-time where it is stored in a history file for post-pass processing and offline trending. Real-time housekeeping telemetry is forwarded to the MOC in real-time and processed and displayed by the MOC system. This telemetry is used by the FOT to assess the spacecraft health and safety and guides any operations they plan during the contact. Tracking services, spacecraft clock mainenance, and center frequency maintenance will nominally be provided by the Tracking Data and Relay Satellites (TDRS), operated by the Space Network, NASA code 530. All network lines will be provided by the NASCOM division of NASA.
Science data will be downlinked at a nominal rate of 300 Mbps to the Landsat Ground Station (LGS) (Two streams of 150 Mbps, each at a different frequency. Each stream is made up of 75 Mbps i and q channels.). The LGS, located at EDC will receive the data via a 10m class X-band antenna and pass it to the Landsat Processing System (LPS). Documentation on the LPS is available at http://lps-server.gsfc.nasa.gov/. Payload data downlinked to Alaska and Svalbard will be at 150 Mbps and will be captured at the site on tape, and shipped to the LGS. LGS will then play the tapes back into the LPS. Data will be processed to level zero and passed to the EDC DAAC (also known as the LP-DAAC) for permanent archive. EDC DAAC is the responsibility of EOSDIS Core System (ECS), and will perform user interface and billing functions. Data in the EDC DAAC will be stored in a format known as Hierarchical Data Format (HDF). The Image Assessment System (IAS) will process a limited number of scenes each day to level 1 in order to ensure that the system is populating the archive with valid data.

A Level 1 processing feature is now planned for user products.

It is the responsibility of the Mission Readiness office of NASA to ensure that the ground system meets all levied requirements.

Click below to see a context diagram that shows the interaction between the different elements.

System Elements and Context Diagrams

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This page was last updated on Dec 23, 1996.
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