South Africa's first nano- satellite experienced two very close encounters with defunct satellites in the past few days after three months in orbit, authorities said on Monday.
The nano-satellite, the ZACUBE-1, came within an estimated 185m of the defunct Russian COSMOS 2151 satellite over Antarctica on Wednesday, the South African Department of Science and Technology (SADST) said in a statement.
Remarkably, a second warning was received on Thursday, with ZACUBE-1 predicted to come within 85m of yet another defunct Russian satellite, METEOR 2-5, over Brazil.
ZACUBE-1 was developed by the Cape Peninsula University of Technology (CPUT) and launched on Nov. 21 2013. The CPUT has independently confirmed with its ground station that ZACUBE-1 is still beaconing and has survived both close encounters.
There is nothing that can be done to alter the course or altitude of ZACUBE-1 as it has no propulsion control, the SADST said, adding that the other two defunct satellites can also not be maneuvered.
There is a margin of uncertainty in the predicted paths of the satellites, and all close encounters of this nature can result in collision.
Accidental collisions of space objects are, however, extremely rare, with only two incidents reported since the beginning of space exploration. The risk of collision increases with the number of objects launched, which necessitates technical and regulatory measures to mitigate space debris for the future sustainable use of outer space. Space Daily Read More>>>>