The first was a high-resolution imaging unit able to measure, water, ice, dust and aerosols in the planet"s atmosphere. An infrared spectrometer would monitor radiance from the planet"s surface and atmosphere, measuring the surface temperature and amounts of dust in the atmosphere. Hope"s ultraviolet spectrometer, meanwhile, would measure the planet"s entire atmosphere and study its levels of hydrogen and oxygen – the building blocks of water, the key to life.