ESA Earth Explorer 7 candidate, PREMIER (Process Exploration through Measurement of Infrared and Millimetre-wave Emitted Radiation) would study trace gases, radiation and chemistry in the upper troposphere and lower stratosphere with an infrared limb-imaging spectrometer and millimetre-wave limb sounder. ESA selected Biomass for Earth Explorer 7 in 2013 while recognizing PREMIER’s potential value; PREMIER remains a documented research concept rather than an implemented mission.