The STARDUST mission will capture cometary particles in aerogel similar to those shown here. The unique properties of the aerogel enable the particles to be soft-captured so as to minimize the impact damage and better preserve them for study.

Fig. 1 Meteoroid Captured in Aerogel

A 1.5 mm long impact track of a meteoroid captured inaerogel exposed to space by the EURECA spacecraft (European Recoverable Carrier) is shown in Figure 1. The wide end (open end) of the "carrot" is the location of hypervelocity entry into the 0.05 g/cc aerogel. As the particle is slowed by the aerogel the track narrows to a point. The 10 micron projectile is seen at the tip of the "carrot".

Figure 2, shows a 10 micron interplanetary dust collected in the stratosphere with a U2 aircraft. This particle is similar in elemental composition to primitive meteorites but differs in having higher carbon and volatile element abundance. The particle is composed of glass, carbon and many types of silicate mineral grains.

	Fig. 2.  Interplanetary Dust Particle

It is a sample of either an asteroid or a comet. The porosity and unusual mineralogical composition suggests that it may be of cometary origin. In the first hour of examination of the returned STARDUST samples it will be possible to determine whether this particle or any other type of meteoritic material is similar or related to comets.

Fig. 3.  GEMS Dust Particle

GEMS (glass with embedded metal and sulfides) are a major sub-subcomponent of one of the most primitive classes of interplanetary dust (see Figure 3). GEMS are usually a few 1000 angstroms in diameter and are composed of glass with large numbers of 10nm size (100A) rounded grains of FeNi metal and sulfide. Individual GEMS show evidence of radiation processing consistent with exposure in the interstellar medium. GEMS may be preserved interstellar grains that were encorporated into early solar system bodies.

	Fig. 4.  Glass Sphere

Figure 4, shows a SEM (scanning electron microscope)photo of a 50 micron glass sphere shot into 0.05 g/cc aerogel at 5 km/s. The cone shaped cap on the spherical projectile is compressed aerogel that built up on the leading edge of the sphere and served as a insulating shield that partially protected the particle. The was launched by the Vertical Gun Facility at NASA Ames Research Center.

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Fig 1. 376x480 23k jpg,   540x690 36k jpg
Fig 2. 619x480 64k jpg,   1138x883 216k jpg
Fig 3. 607x480 84k jpg,   1280x1012 300k jpg
Fig 4. 499x480 46k jpg,   847x814 109k jpg