Spitzer Space Telescope imaging spectrometer observations of comet 9P/Tempel 1 during the Deep Impact encounter returned detailed, highly structured, 5- to 35-micrometer spectra of the ejecta. Emission signatures due to amorphous and crystalline silicates, amorphous carbon, carbonates, phyllosilicates, polycyclic aromatic hydrocarbons, water gas and ice, and sulfides were found. Good agreement is seen between the ejecta spectra and the material emitted from comet C/1995 O1 (Hale-Bopp) and the circumstellar material around the young stellar object HD100546. The atomic abundance of the observed material is consistent with solar and C1 chondritic abundances, and the dust-to-gas ratio was determined to be greater than or equal to 1.3. The presence of the observed mix of materials requires efficient methods of annealing amorphous silicates and mixing of high- and low-temperature phases over large distances in the early protosolar nebula.

The Moon is generally anhydrous, yet the Deep Impact spacecraft found the entire surface to be hydrated during some portions of the day. Hydroxyl (OH) and water (H2O) absorptions in the near infrared were strongest near the North Pole and are consistent with <0.5 weight percent H2O. Hydration varied with temperature, rather than cumulative solar radiation, but no inherent absorptivity differences with composition were observed. However, comparisons between data collected 1 week (a quarter lunar day) apart show a dynamic process with diurnal changes in hydration that were greater for mare basalts (approximately 70%) than for highlands (approximately 50%). This hydration loss and return to a steady state occurred entirely between local morning and evening, requiring a ready daytime source of water-group ions, which is consistent with a solar wind origin.