Spectrometers

New Horizons's ultraviolet imaging spectrometer, which probed the composition and structure of Pluto's atmosphere as the spacecraft flew through its shadow.

Galileo's imaging spectrometer, which mapped the composition of Jupiter's moons and found evidence for salts and a subsurface ocean on Europa.

An instrument that measures the gamma rays and neutrons emitted by a surface under cosmic-ray bombardment, revealing elemental composition — and, through neutrons, the presence of water or ice.

An instrument that sorts atoms and molecules by mass, identifying the chemical and isotopic makeup of a sample of gas or dust — essential for atmospheres, plumes, and returned samples.

MESSENGER's spectrometer, which measured the elemental composition of Mercury's surface and helped confirm water ice in its permanently shadowed polar craters.

An instrument that splits light into its component wavelengths to reveal composition, temperature, and motion — the workhorse of remote sensing, spanning ultraviolet, visible, infrared, X-ray, and gamma-ray bands.