PROCYON
[1] It was intended to flyby the asteroid (185851) 2000 DP107 in 2016,[2] but the plan was abandoned due to the malfunction of the ion thruster.On 22 February 2015, the ion engine was started, with the intention of adjusting the orbit so that an Earth flyby in December 2015 would direct the probe towards asteroid 2000 DP107.[3] Initial results were favourable - the engine delivered 330 μN of thrust rather than the designed 250 μN - but the engine failed on 10 March and could not be restarted; PROCYON flew past Earth on 3 December 2015, but was unable to make a controlled orbit change.[5] A novel subsystem tested by PROCYON involved feeding both the main ion engine and the eight attitude control cold-gas thrusters from the same tank (containing 2.5 kg of xenon at launch) PROCYON observed the Lyman-alpha emission of comet 67P/Churyumov–Gerasimenko to determine its overall coma structure.[7] PROCYON captured the first complete image of the geocorona, confirming for the first time that it has north-south symmetry.