Naval Research Laboratory scientists analyze Comet Wild 2 samples

December 22, 2006

(Washington, DC • 12/22/06) - Scientists at the Naval Research Laboratory (NRL) have analyzed samples from Comet Wild 2, as part of NASA's Stardust mission, the first solid sample return mission since Apollo. Over one hundred scientists at various institutions participated in the preliminary analysis. NRL contributed to the Mineralogy and Petrology, Crater, Bulk Chemistry and Isotope analysis teams by studying the structure and composition of the comet samples using transmission electron microscopy (TEM).

The TEM studies carried out by Dr. Rhonda Stroud and Dr. Thomas Zega, from NRL's Materials Science and Technology Division, demonstrated that micrometer-sized Mg-rich silicates and nanoscale Fe-sulfides are primary components of the cometary material. The samples studied at NRL included both grains captured in aerogel (Figure 1) and aluminum foil (Figure 2). Comparative analysis of samples collected in each media is important for distinguishing the primary characteristics of the cometary grains from capture artifacts. To conduct these studies, the NRL researchers made use of world-class TEM and focused-ion-beam microscopy (FIB) facilities maintained by the Materials Science and Technology Division and the Nanoscience Institute. FIB techniques for extracting the micrometer-sized cometary residue from foil craters were developed at NRL with support from the NASA SRLIDAP program.

Stardust was the first NASA mission dedicated to exploring a comet. The mission robotically collected comet samples in deep space and returned them to earth. Stardust passed within 149 miles of Comet Wild 2 in January 2004. The spacecraft passed Comet Wild 2 at 13,000 mph, over six times faster than a speeding bullet. The thousands of comet particles were captured using a material called aerogel, which is a special type of foamed glass, made so lightweight that it is barely visible and almost floats in air. Most of the particles collected are smaller than the width of a human hair. To collect the comet samples, Stardust traveled two-billion miles to meet Comet Wild 2 and then another one-billion miles to get back home. The samples returned to Earth in January 2006, and the preliminary analysis was conducted until August. The preliminary results appear in the December 15 issue of Science. Continued analysis of more of the Stardust cometary samples is ongoing.
-end-
Fig. 1 Bright-field TEM image of a mineral assemblage from Comet Wild 2. Mg-rich silicates, such as pyroxene (MgSiO3; Px) are intermixed with amorphous silicates (Am) and nanoscale Fe-Ni sulfides (black arrowheads). The aerogel capture material occurs around the assemblage.

Figure 2 A crater in aluminum foil containing Wild 2 comet material. B. Scanning transmission electron micoscope image of an extracted slice of the crater. C. a Principal component map identifying the cometary material components: red = iron-nickel sulfide; blue= magnesium-silicate; yellow = aluminum foil capture medium; green = protective carbon coating.

Naval Research Laboratory

Related Comet Articles from Brightsurf:

Comet Chury's ultraviolet aurora
On Earth, auroras, also called northern lights, have always fascinated people.

Hubble snaps close-up of comet NEOWISE
The NASA/ESA Hubble Space Telescope has captured the closest images yet of the sky's latest visitor to make the headlines, comet C/2020 F3 NEOWISE, after it passed by the Sun.

Hubble snaps close-up of celebrity comet NEOWISE
The Hubble Space Telescope has snapped the closest images yet of the sky's latest visitor to make headlines, comet NEOWISE, after it passed by the Sun.

New comet discovered by ESA and NASA solar observatory
In late May and early June, Earthlings may be able to glimpse Comet SWAN.

Hubble captures breakup of comet ATLAS
The NASA/ESA Hubble Space Telescope has provided astronomers with the sharpest view yet of the breakup of Comet C/2019 Y4 (ATLAS).

The salt of the comet
Under the leadership of astrophysicist Kathrin Altwegg, Bernese researchers have found an explanation for why very little nitrogen could previously be accounted for in the nebulous covering of comets: the building block for life predominantly occurs in the form of ammonium salts, the occurrence of which could not previously be measured.

New NASA image provides more details about first observed interstellar comet
A new image from NASA's Hubble Space Telescope provides important new details about the first interstellar comet astronomers have seen in our solar system.

Interstellar comet 2I -- Borisov swings past sun
Comet 2I/Borisov is a mysterious visitor from the depths of space -- the first identified comet to arrive here from another star.

Hubble observes 1st confirmed interstellar comet
Hubble has given astronomers their best look yet at an interstellar visitor -- comet 2I/Borisov -- whose speed and trajectory indicate it has come from beyond our solar system.

Interstellar Comet with a Familiar Look
A new comet discovered by amateur astronomer Gennady Borisov is an outcast from another star system, yet its properties determined so far are surprisingly familiar -- a new study led by JU researchers shows.

Read More: Comet News and Comet Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.