japan_dan writes "Two ESA spacecraft will observe 21 Lutetia during Rosetta's flyby on 10 July: Rosetta from 3,160 km and Herschel from 450 million km. Herschel's PACS and SPIRE spectrometers will view Lutetia in far infrared, while Rosetta will gather data in a variety of wavelengths. Since the observations will be coordinated during and at closest approach, scientists will later be able to correlate the data to produce a map of the thermal radiation emitted by Lutetia. There are a pair of animations modelling the expected temperature distribution over Lutetia at the link. The joint observations are part of a series of 8 sessions planned in the next couple of years by Herschel scientists to study objects that will be visited by spacecraft."