High Quality Content by WIKIPEDIA articles! The UCL Mullard Space Science Laboratory (MSSL) is the United Kingdom`s largest university space research group. MSSL is the Department of Space and Climate Physics of the University College London. UCL was one of the first universities in the world to conduct space research. MSSL has participated in 35 satellite missions, 10 of which are currently in operation and over 200 sounding rocket experiments since its establishment.