On the beautifully clear Monday morning of Feb. 11, 2013, the Landsat Data Continuity Mission made its way from California’s Vandenberg Air Force Base to low Earth orbit. The more than 1,000 Landsat scientists, engineers, data users, and fans gathered to watch the launch breathed a collective sigh of relief as the bright orange light of the rocket’s booster faded into the distance and a successful launch—one of Vandenberg’s smoothest according to Launch Control—was declared. But after years of formulation, planning, fabrication, and testing, the satellite’s work had just begun.
Like a massive seafaring ship, a satellite is not ready for active service until a commissioning process takes place. You don’t launch a satellite on a Monday and get science data back on Tuesday. For the Landsat Data Continuity Mission (LDCM) an approximately 100-day commissioning, or on-orbit checkout period, occurs before the satellite can be declared operational.
The commissioning process is a highly coordinated effort that proceeds at a swift pace involving over a hundred people directly and hundreds more tangentially. The major players during on-orbit checkout are the Mission Operations Team, the Ground Systems Team, and the Calibration and Validation Teams. These teams closely coordinate to make sure the spacecraft and instruments are operating correctly and that measurements made by LDCM’s two science instruments are accurate and that they are successfully transmitted back to the ground, processed, and made readily available to the public.
“Right after launch and for the first week or so, day-to-day operations are very busy,” says Vicki Dulski, the LDCM Ground System and Operations Manager. “The team must execute a series of procedures to send commands from the ground to the observatory in order to power on and activate all of the spacecraft subsystems and instruments.”
To ensure that the Mission Operations Team can flawlessly follow the strict timeline of commands needed to verify that the satellite is working properly after launch, the sequenced procedures are carefully rehearsed prior to launch.
These important first steps initiate the on-orbit checkout. The commissioning effort can be broken down into five major components: (1) subsystems and communication checkout, (2) instrument initiation, (3) data processing, (4) calibration activities, and (5) orbit placement. During the 100-day checkout period, the commands, testing, and data collection necessary for these commissioning components overlap in a carefully choreographed manner.
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