Landsat 8 Status Update for Aug. 8, 2013
Landsat 8 officially began normal operations on May 30, 2013, when the leadership for satellite operations transferred from NASA to the U.S. Geological Survey. With the hand-off, the name of the satellite changed from the Landsat Data Continuity Mission to Landsat 8. The USGS now manages the satellite flight operations team within the Mission Operations Center, which remains located at NASA’s Goddard Space Flight Center in Greenbelt, Md.
The transition followed a 100-day commissioning period during which NASA and the USGS systematically checked out all of the spacecraft and ground subsystems and raised the satellite to its operational orbit at 438 miles (705 kilometers) altitude. Analyses of data collected during this check-out period show that the satellite, sensors and ground system performance metrics exceed specifications in most respects.
Landsat 8 data products are now available to the public from the USGS Earth Resources Observation and Science, or EROS, Center in Sioux Falls, S.D. EROS opened the Landsat 8 data archive on the first day of normal operations, providing immediate access to more than 22,000 scenes collected since April 12, 2013, the day the satellite ascended to its operational orbit. Since May 30, EROS has added more than 400 Landsat 8 scenes per day to the archive. As with all the Landsat data in the EROS archive, anyone can search the archive and order Landsat 8 data products for free using search tools provided on the USGS website. These tools include EarthExplorer, GloVis and the LandsatLook Viewer.
On July 21, the flight operations team performed a maneuver to avoid a possible collision between Landsat 8 and another orbiting object. The maneuver also served to make up for atmospheric drag, and the satellite returned to its Earth-observing mode.
On July 30, the communication and public engagement team launched a redesigned Landsat science website: http://landsat.gsfc.nasa.gov, with more than 900 pages of content, 638 images, audio, video and more.
LDCM Status Update for May 17, 2013
All spacecraft systems and instruments are performing normally. On Sunday, May 5, the Flight Dynamics Team fired thrusters for 0.8 seconds on the Landsat Data Continuity Mission, or LDCM, Observatory to mitigate the risk of colliding with a piece of space junk. The burn also boosted the satellite as part of a planned atmospheric drag make-up maneuver. Afterward, the spacecraft safely returned to Earth-observing mode.
Through May 5, the satellite was routinely imaging more than 400 scenes per day, continuing routine calibrations and testing off-nadir (“nadir” means straight down) imaging. Additionally, real-time data was downlinked to international collaborator ground stations.
Then on Monday, May 6, the Operational Land Imager, or OLI, went into safe mode after a corruption event in unused memory. The cause was likely a result of a hit of higher than usual radiation from Earth’s inner Van Allen radiation belt over the South Atlantic Ocean. The anomaly was considered benign with no long-term effects on the mission. The OLI performed as designed by detecting the anomaly and placing itself in safe mode to protect the health of the instrument. On Friday, May 10, OLI was successfully returned to operation without incident.
On May 15, the team successfully completed the LDCM On-orbit Acceptance Review, which allows NASA’s Goddard Space Flight Center in Greenbelt, Md., to accept all contractual obligations for the spacecraft, the Operational Land Imager, and the Mission Operations Element from industry partners.
LDCM Status Update for May 2, 2013
All spacecraft and instrument systems continue to perform normally. LDCM continues to collect more than 400 scenes per day and the U.S. Geological Survey Data Processing and Archive System continues to test its ability to process the data flow while waiting for the validation and delivery of on-orbit calibration, which convert raw data into reliable data products.
During this period, routine calibrations have continued along with Operational Land Imager and Thermal Infrared Sensor instrument imaging. Lunar calibrations were performed during last week's full moon. As of April 24, 2013, the new system for scheduling image collection, the Collection Activity Planning Element is operational. On April 26, 2013, a 1.2-second thruster burn was conducted to maintain the observatory on the proper ground track and counteract drag on the satellite from the atmosphere.
Then on Saturday, April 27, 2013, LDCM began a 16-day imaging and calibration cycle that is a demonstration of the operational cycle the satellite will follow for the life of the mission. This dress rehearsal will test the entire image planning, collection and processing system at operational rates to verify everything is ready for handover to USGS for routine operations in late May.
LDCM Status Update for April 24, 2013
All spacecraft and instrument systems continue to perform normally. LDCM continues to collect more than 400 scenes per day on the Worldwide Reference System-2 track. While waiting for the validation and delivery of on-orbit calibration information that ensures the instruments are returning good data, the Data Processing and Archive System at the U.S. Geological Survey's Earth Resources Observation and Science (EROS) Center is being tested to demonstrate the ability to process this flow of data. During this period, routine calibrations have continued along with OLI and TIRS imaging. The satellite completed its 1,000th orbit on April 21, 2013.
LDCM Status Update for April 16, 2013
All spacecraft and instrument systems continue to perform normally. Two ascent burns were performed in the last week. On Sunday, April 7, ascent burn No. 3 was conducted. The 56.2-second burn was the longest LDCM burn yet, bringing the satellite within range of its operational orbit. Early Friday morning, April 12, ascent burn No. 4 was performed. This 50.5-second burn delivered LDCM to its operational orbit altitude of 705 kilometers (438 miles). Additionally, an inclination burn was successfully executed on Sunday, Apr. 14, and a trim maneuver was not needed.
"After many years in the making, LDCM has reached her final home," said LDCM Project Manager Ken Schwer.
During this period, OLI and TIRS imaging have continued. The calibration team continues their trending work to refine the instruments' pre-launch calibration.
LDCM Status Update for April 5, 2013
All spacecraft and instrument systems continue to perform normally. LDCM under-flew the Landsat 7 satellite from Friday, Mar. 29, to Sunday, Mar. 31, collecting more than 1,200 coincident scenes. The scenes were acquired over a variety of different landscapes.
During this period two coordinated field campaigns also took place: one in Dolan Springs, Ariz., the other in California. The field campaigns were timed so that ground- and air-based measurements could be made simultaneously with tandem Landsat 7/ LDCM data collects. The NASA and USGS calibration teams are using the collected data to refine LDCM’s pre-launch calibration in preparation for the public release of data beginning in late May—after the on-orbit check-out is complete, the satellite reaches its operational altitude, and operations are formally handed over to USGS.
LDCM Status Update for March 29, 2013
All spacecraft and instrument systems continue to perform normally. LDCM’s two instruments have been ramping up their Earth image collects, and on March 27, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) hit the 400 scenes per day mark. This is the data acquisition volume set forth in the specifications for LDCM and will be the operational acquisition standard.
Beginning on Friday, March 29, LDCM will under-fly Landsat 7, allowing the two satellites to collect coincident data that can be used for cross-calibration. The LDCM calibration team is evaluating data collected during this on-orbit check out period and adjustments will be made as necessary so that the LDCM data accurately reflects Earth’s radiance when operations are handed over to USGS and data are made available to the public in late May.
Other ongoing activities during the past week included the first OLI stellar calibration. This maneuver involved maneuvering the satellite so that it could view a designated star field so that the pointing accuracy of OLI could be evaluated. Additionally, tests of the X-band communication downlinks to six international ground stations occurred. International partners in Darwin, Australia; Alice Springs, Australia; Parepare, Indonesia; Kiruna, Sweden; Matera, Italy; and Neustrelitz, Germany, successfully downloaded test data.
The Mission Ops team also successfully performed a “blind” acquisition test using the Sioux Falls, S.D., ground station. This operation tested Mission Ops ability to communicate with the satellite in the event that no communication is scheduled, but that telemetry and commanding is necessary, triggering the need for the satellite transmitter to be turned on via ground command.
LDCM Status Update for March 15, 2013
All spacecraft and instrument systems continue to perform normally. This week's activities were dominated by two ascent burns to raise LDCM's orbit a little closer to its final operational orbit of 438 miles (705 kilometers) above Earth's surface. The first burn occurred on March 10 and the second on March 13. Both went as planned. The final two ascent burns are planned for April.
Other ongoing activities include the continued check out of TIRS and OLI, and exercising of file management procedures for the onboard Solid State Recorder.
LDCM Status Update for March 8, 2013
All satellite and instruments continue to perform normally. The Mission Operations team completed another round of Attitude Control System calibration maneuvers late last week. In addition, they tested the spacecraft's ability to execute uploaded commands while the satellite is out of range of ground stations, called stored command loads.
The Mission Operations team also conducted a series of data flow tests that exercised the entire image data transmission and processing functionality of the satellite and ground system using test patterns internally generated by the OLI and TIRS instruments. In these tests, the satellite successfully stored the instrument test pattern data in the onboard Solid State Recorder, and then transmitted that data to the ground when it flew back into range of the ground station. The Data Processing and Archive System (DPAS) at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, S.D., then successfully processed these test patterns as if they were Earth image data. These tests demonstrate the readiness of the entire LDCM satellite and ground system to successfully collect real Earth imagery.
The OLI and TIRS instruments continue to progress toward coming online. OLI had a successful checkout of its diffuser mechanism, which is part of OLI’s calibration system. The main activities this week, however, focused on TIRS. On March 4, the Mission Operations team successfully deployed the TIRS Earth shield from its launch position. The Earth shield is a large panel that blocks heat from Earth from getting onto the TIRS thermal radiators, thus increasing the efficiency of those radiators. Over the past few days the team has checked out the mid-stage heaters, powered up systems, including the Focal Plane Electronics Box, and tested the Scene Select Mirror. On March 6, the TIRS cryocooler was turned on and successfully cooled the sensors to 43 kelvins (-352 F).
LDCM Status Update for March 1, 2013
All satellite and instrument systems continue to perform normally. The Mission Operations team successfully completed a number of Attitude Control System (ACS) calibration maneuvers, which involve pointing the spacecraft in different orientations to ensure that the spacecraft can point the instruments in the various positions needed for data collection, and solar and lunar calibration reference checks.
The ground system has also been put through its paces. After receiving test data, the Landsat Ground Station in Sioux Falls, S.D., successfully replaced an incorrect cable in their system for receiving telemetry. The system for sending commands and receiving telemetry is now fully redundant. The Svalbard Ground Station, located in northern Norway, tested its S-band telemetry link to the Mission Operations Center and LDCM with normal results. The link transfers data at 1.0 Mbps.
Instrument check-out continues to go well. The TIRS cryocooler, which will maintain the operating temperature of the sensors at 43 kelvins (-382 F), was successfully deployed from its launch position. For OLI, the team successfully loaded the OLI pixel map, which optimizes performance. The instruments are not yet imaging Earth.
Throughout, more test pattern data has been generated and transmitted to the Data Processing and Archive System in Sioux Falls, S.D. As of Feb. 26, 104 test pattern images have been processed.
Because the Atlas rocket and Centaur upper stage placed LDCM within its optimal preliminary orbit, the Mission Operations team did not have to do an inclination adjust maneuver/burn, which was planned to correct LDCM's orbit after launch. This saved the mission 12 kilograms of fuel, an amount equal to the fuel needed to maintain the nominal LDCM orbit for two to three years.
LDCM Status Update for Feb. 21, 2013
The LDCM Mission Operations Team successfully completed the first phase of spacecraft activation. All spacecraft subsystems have been turned on, including propulsion, and power has been supplied to the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS). The two instruments are currently undergoing a heated dry-out process to ensure water and other potential contaminants are eliminated from the optics and detectors. Cool down of the instruments to enable Earth imaging should begin in a few weeks.
The operations team also conducted a data exchange between the spacecraft, instruments, and ground system for an early look at data processing. OLI and TIRS test pattern data were generated and downlinked to ground stations in Sioux Falls, S.D., Gilmore Creek, Alaska, and Svalbard, Norway. All three ground stations received the data files with no errors, and then the test data were successfully transferred to the USGS Data Processing and Archive System in Sioux Falls, where the data were initially processed and archived.
LDCM Status Update for Feb. 14, 2013
The satellite is performing extremely well and is now pointing at Earth. Spacecraft activation continues. The mission operation team continues to work minor ground system configuration issues.