The University of Wurzburg Experimental-4 cubesat, from the German researchers, has just avoided a possible collision in the early days of July. It did that by lowering its altitude using the NANOFEEP electric propulsion system, powered by Morpheus Space. This is the first time in history that a one-unit cubesat performs a collision-avoidance maneuver of any kind, according to the president and co-founder of Morpheus, Istvan Lorincz.
It would seem that small satellites keep growing in popularity, which leads many companies all around the globe to develop some small-scale thrusters that are able to assist cubesats in avoiding any sort of collisions, changing their altitude, even performing more complex tasks such as flying in formation and completely exiting their orbit once their mission is concluded.
Starting on 23 June until 3 July, the cubesat with the code number UWE-4 fired its thrusters of the NanoFEEP kind many times in a row in an effort to drop its altitude by over 100 meters. To compare, the natural orbital decay in this case and in the same timeframe would have been 21 meters. This information was given in a news release performed by the University of Wurzburg.
The University of Wurzburg received a warning regarding a possible collision with a long-retired satellite based on Iridium from the U.S. Air Force 18th Space Control Squadron. This warning was given quite recently, on 2 July. After staff from the UWE-4 mission personnel looked at the situation, they decided that the only way for the UWE-4 to not collide with the retired Iridium satellite is for it to orbit at a significantly lower altitude. They have then completed the analysis and started to fire the thrusters of the cubesat at such a level as to lower its altitude by 100m meters. No further messages were received by the University and no accident ever occurred.