At 7 pm on August 15th 2014, VNREDSat-1 conducted operations to adjust its orbit to avoid the possibility of collision with an object flying across the current orbit with a velocity of approximately 14,000 m/s.
After receiving notification from the U.S Joint Space Operations Center (JSPOC) which warned of the possibility of a collision between VNREDSat-1 and an unknown object at 8:26 pm (Vietnam time) on August 15th 2014, with a probability of collision calculated at 0.297% (with the collision probability of 0.1%, it is necessary to adjust orbit), the Center for Small Satellite Control and Exploitation conducted analysis and accessed the situation, consulted experts from Astrium (France), Satellite Control Center of GISTDA (Thailand) and decided to adjust the orbit to ensure absolutely safety for the VNREDSat-1.
The adjustment calculation was deployed efficiently and implemented correctly to avoid any collision, to save satellite’s fuel and ensure continuity in the implementation of the image capture plan. The order of adjusting orbit must be uploaded on the satellite at least 30 minutes before the predicted collision time. Meanwhile, the latest communication session with the satellite at a satellite control trans-receiver station at Hoa Lac was 9 p.m. on August 15th 2014. There, the Center for Small Satellite Control and Exploitation urgently set up a satellite link with VNREDSat-1 through signal trans-receiver station in Kiruna (Sweden).
At 3:39 pm (Vietnam time) on August 15th 2014, the center finished sending commands to adjust orbit on the satellite. At 7:00 pm, the satellite performed orbit adjustments. At 9:00 pm, when the satellite had a working session with Hoa Lac station, satellite data was downloaded and identified the success of urgent adjustment operation. Then, the satellite continued operating stably, captured and sent images regularly as planned. It can be said that this is the most complicated VNREDSat-1 orbit adjustment that the Center for Small Satellite Control and Exploitation has conducted so far.
Translated by Tuyet Nhung
Link to Vietnamese Version