By Dr. Gary L. Deel, Ph.D., J.D.
Faculty Director, School of Business, American Military University
IKONOS was a commercial Earth observation satellite that was launched in September 1999. It operated for almost 16 years until its decommissioning in March 2015. During its lifetime IKONOS took a total 597,802 images.
IKONOS was operated by a U.S. company called DigitalGlobe, and its primary mission was to capture high-resolution images of Earth for commercial use. Its orbit was nearly spherical with a perigee of 678 km and an apogee of 682 km. The inclination was 98.2° and the orbital period was 98.4 minutes.
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IKONOS was capable of capturing a 3.2m multi-spectral, near-infrared, .82m panchromatic resolution at its nadir. This means it was able to provide very detailed, high-resolution photos that could be used for such purposes as mapping natural resources, monitoring natural disasters, tax mapping, agriculture and forestry, mining, engineering, construction, and change detection.
IKONOS’s communications worked in two methods. Downlink for image data was transmitted to ground in X-band radio telemetry, tracking, and control (TT&C); uplink was accomplished via S-band. IKONOS communicated with ground stations associated with all of its international affiliates at various assigned times.
The satellite was powered by three solar panels that together produced about 1.5 kW of power. Total system power consumption onboard IKONOS was approximately 350 W.
IKONOS was built on a Lockheed Martin LM-900 satellite bus. The body of the spacecraft was a hexagonal design 1.83m long by 1.57m wide. The satellite weighed about 817 kg or approximately 1,800 pounds.
The LM-900 bus had a passive design with redundant heater systems and radiators to manage temperature. Additionally, the optical sensor assembly (OSA) inside IKONOS was built with low thermal expansion materials so that any changes in temperature would not affect the functionality of the telescopes and cameras.
IKONOS used a combination of sensors to determine attitude in its flight. These sensors included two star trackers and one sun sensor. The attitude control system consisted of reaction wheels that allowed the spacecraft to stabilize itself along three different axes.
Data onboard IKONOS was stored in a 64GB solid state drive before transmission to ground. The spacecraft was equipped with a RAD-750 flight computer for processing data.
IKONOS used GPS for navigation, but was controlled by ground stations in affiliate countries that participated in the program. Each country was assigned intervals of time to task IKONOS as it passed into their communications zones during each orbit.
The propulsion system on the LM-900 platform was composed of blow-down hydrazine monopropellant thrusters to maintain desired orbital altitude and dynamics.
IKONOS is no longer in operation, but its work has been taken on by newer and more-advanced imaging satellites that provide even higher resolution imagery for modern commercial and governmental needs.
About the Author
Dr. Gary Deel is a Faculty Director with the School of Business at American Military University. He holds a J.D. in Law and a Ph.D. in Hospitality/Business Management. Gary teaches human resources and employment law classes for American Military University, the University of Central Florida, Colorado State University and others.