Comet NEOWISE was first observed by NASA's NEOWISE spacecraft on Valentine's Day, 2014. This heat-sensitive infrared image was made by combining six exposures taken by the NEOWISE mission of the newly discovered comet.
Three of NASA's contributions to the ESA's Rosetta mission are pictured here: an ultraviolet spectrometer called Alice (top), the Ion and Electron Sensor (IES) (bottom left), and the Microwave Instrument for Rosetta Orbiter (MIRO) (bottom right).
New measurements from NASA's Herschel Space Observatory have discovered water with the same chemical signature as our oceans in a comet called Hartley 2 (pictured at right). The image at bottom right is an artist's concept of a comet.
This composite image shows the three small worlds NASA's Stardust spacecraft encountered during its 12 year mission. Stardust performed a flyby of asteroid Annefrank in 2002, Comet Wild in 2004, and Tempel 1 in 2011.
This 3-D image shows the region where NASA's Deep Impact mission sent a probe into the surface of comet Tempel 1 in 2005. This picture was taken six years after the Deep Impact collision. 3D glasses are necessary to view this image.
This image shows the surface of comet Tempel 1 before and after NASA's Deep Impact mission sent a probe into the comet in 2005. The region was imaged by Deep Impact before the collision (left), then six years later on by NASA's Stardust-NExT mission.
This series of images shows the area where NASA's Deep Impact probe collided with the surface of comet Tempel 1 in 2005. The view zooms in as the images progress from top left to right, and then bottom left to right.
This image layout depicts changes in the surface of comet Tempel 1, observed first by NASA's Deep Impact Mission in 2005 (top right) and again by NASA's Stardust-NExT mission on Feb. 14, 2011 (bottom right).
This image obtained by NASA's Stardust spacecraft shows a side of the nucleus of comet Tempel 1 that has never been seen before; three terraces of different elevations are visible, with dark, banded scarps, or slopes, separating them.
This image mosaic shows four different views of comet Tempel 1 as seen by NASA's Stardust spacecraft as it flew by on Feb. 14, 2011. The images progress in time beginning at upper left, upper right, to lower left, then lower right.
This composite image was taken by NASA's Stardust navigation camera 42 hours before its encounter with comet Tempel 1. The spacecraft is due to encounter the comet in the evening hours of Feb. 14, 2011.