Hypervelocity impacts on HST solar arrays and the debris and meteoroids population

Laboratory simulation of impacts on aluminum foils of the Stardust spacecraft: Calibration of dust particle size from comet Wild‐2

“…It has not yet been convincingly demonstrated that much smaller silicate particles (e.g., 1 µm in diameter) will leave recognizable traces in aerogel. Evidence from interplanetary dust detectors (e.g., Gr¸n et al 1992Gr¸n et al , 1995 and from spacecraft materials returned from low-Earth orbit (LEO) (e.g., Moussi et al 2005) suggests that there are abundant micrometeoroids of micron scale, although the relative contribution from asteroid and comet sources has not yet been firmly established.…”

“…Many spacecraft surfaces exposed to space in LEO have been examined for signs of impact damage (e.g., Warren et al 1989;Humes 1991;See et al 1994;Zolensky et al 1994;Love et al 1995;Bernhard and Hˆrz 1995;Graham et al 2001;Moussi et al 2005). Metal surfaces present a relatively hard and dense substrate and may therefore result in high levels of modification to the impacting particle (Bernhard et al 1994a;Graham et al 2001) during the creation of a distinctive bowl-shaped crater.…”

“…For surfaces that have been returned from LEO, difficulties attend the interpretation of the mass of individual impacting particles due to unconstrained variables, i.e., the crater characteristics reflect their mass and velocity, both unknown quantities that have no simple and unambiguous individual proxies. Surveys of spacecraft impact damage (e.g., Moussi et al 2005) derive flux models detailing numbers of specific particle size, but need to rely upon assumptions of a mean velocity as well as density for micrometeoroids, which cannot fully reflect the diverse range of natural particle populations. The apparently circular outline of most impact craters may also poorly reflect the diversity of incidence angles and therefore can mask a range of effective impact velocities.…”

The chemical composition of micrometeoroids impacting upon the solar arrays of the Hubble Space Telescope

“…These values represent the largest impact flux measurement campaigns on a single substrate that has ever been mounted in orbit and are between one and two orders of magnitude larger than the threshold (2.5 m 2 a) for reliable statistical sampling of the mid range micrometeorite population ($150 lm) demonstrated by Peucker-Ehrenbrink and Ravizza, 2000. Although the mass flux is concentrated in the larger particles, the smaller grains (<20 lm) are present in much larger numbers (more than ten times, Moussi et al, 2005), and a reliable measurement of their numbers can therefore be made in a sample of smaller area-time product. As the attribution of micrometeoroid origin within our study is based upon residue analysis, we are also able to exclude a contribution from high eccentricity geostationary transfer orbit space debris (mainly solid rocket motor exhaust products, Hörz et al, 2002), thereby removing a flux component that was not recognised in the seminal work on the space-facing surface of the Long Duration Exposure Facility (Love and Brownlee, 1993).…”

“…In total, over 60 m 2 of array surface was returned by shuttle orbiters, the earlier SM-1 (single) array having been exposed to space in low Earth orbit (LEO) at an altitude of about 615 km for 3.6 years, and the two arrays from SM-3B at a similar altitude for 8.2 years. The survey methodology, areas sampled, and the results from impact feature counting and size measurement are described in McDonnell and Griffiths (1998) and Moussi et al (2005), respectively. In addition to the major survey, individual solar cells (73 from SM-1 and 25 from SM-3B), each measuring 4 cm by 2 cm (Fig.…”