Recent theoretical studies show that orbits of circummartian dust particles are controlled by solar radiation pressure and the Martian oblateness. Smaller dust particles (< 22μm) with enhanced orbital eccentricity are quickly captured by Mars. We find that the collisions of ring particles with Phobos and Deimos are the most important dust sources. Erosion of Phobos should set the upper limit on the dust production efficiency controlling this self-sustaining mechanism, and then the ring dust abundance.

Recently analysed hypervelocity impact data from retrieved satellites are summarised. Analyses of perforation data show that mean densities are low (around 1.5-2 g/cm3), impact velocities are consistent with radar meteor observations and that high aspect ratio particles are not found. Mean data, for Fmax > 30 μm agrees well with the Grün et al. Interplanetary flux model, though there is evidence of a strong bias towards the Earth apex of motion direction. For Fmax < 30 μm the data at LDEF's altitude is dominated by space debris.

Man-made, artificial space debris is of interest to the study of interplanetary dust for two reasons: (1) In many regions of Earth orbital space, the space debris flux is larger than the natural meteoroid flux, complicating the study of interplanetary dust, and (2) models and experiments developed to understand space debris may have application to the study of interplanetary dust. The purpose of this paper is to summarize the space debris environment as it is understood today by characterizing the models used to predict the space debris environment and describing the measurements to test the model predictions.

Within the last 5 years, the space debris environment has been measured by a number of experiments. These experiments have revealed significant sources of debris in addition to the assumed major source of satellite explosions. Understanding these sources has required the development of more complex models and additional insight into the design and operation of spacecraft. Increased awareness of space debris issues at an international level has led to measures that have reduced the rate of growth in the environment. However, the number of new debris sources discovered seems to be proportional to the number of new measurements of the environment.

After the retrieval of the NASA Long Duration Exposure Facility (LDEF), postflight investigations started on the Interplanetary Dust Experiment (IDE). The time- and orientation resolved dataset was processed at the Institute for Space Science and Technology (ISST) in Gainesville, FL, residue chemistry analyses were conducted at the Analytical Instrumentation Facility at North Carolina State University (NCSU-AIF), Raleigh, NC, and system-level tests were performed at NASA Langley Research Center (LaRC) in Hampton, VA, among other investigators. With the end of the postflight investigation program it was considered compulsory to archive all data in a format that would facilitate future analyses.

The recent recovery of the Hubble Space Telescope (HST) Solar-Array-1 offers a unique opportunity to improve our knowledge of the low Earth orbit (LEO) particle environment. The data from HST surfaces is particularly interesting for the meteoroid and debris community, as the Telescope was in orbit at an altitude of approximately 614 km and there has been no data from such a high orbit before.

The returned solar cells from the European Retrievable Carrier (EURECA) satellite and one Hubble Space Telescope Solar Array (HST-SA) acted as collector surfaces for microparticles in the vicinity of the Earth. Because only limited information on cratering formulae for solar cells was available from the literature, hypervelocity impact experiments on such samples were performed at the plasma drag accelerator facility of the Fachgebiet Raumfahrttechnik (LRT), TU München. The results from these experiments were combined with data from experiments performed during the Apollo program into a new scaling law relating particle parameters and impact crater dimensions on solar cell targets.

STARDUST, a Discovery-class mission, will return intact samples of cometary dust and volatiles from comet P/Wild 2, as well as samples of the interstellar dust moving through the solar system. Dust capture utilizes aerogel, a microporous silica that is capable of intact capture of hypervelocity particles. A navigation camera, an in situ dust analyzer, and a dust flux monitor complete the payload. The Wild 2 flyby takes place in January 2004, with Earth return in January 2006.

In October 1997 a unique mission to the Saturnian system will be launched by NASA, the CASSINI mission. One goal of this mission is to study the Saturnian dust environment, and for this task, the COSMIC DUST ANALYZER (CDA) has been developed and is currently being tested. Impact ionization is used to determine the speed (1 - 100 km/s) and the mass (1•10–15 – 1•10–9 g) of impinging particles. Furthermore, the electric charge (1•10–15 – 1•10–12 C) of the particles can be measured via the induction principle, and an integrated time-of-flight mass spectrometer will analyze the chemical composition of individual dust particles. In order to achieve sufficient sensitivity for dust fluxes as low as 10 particles/(month-m2), the sensor has a large sensitive area of 0.1 m2. This paper will describe the function of the experiment.

PLANET-B is an ISAS spacecraft which will investigate the upper atmosphere and the surroundings of Mars between 1999 and 2001 To clarify the presence and characteristics of the Martian dust ring/torus, an impact ionization dust detector will be on board PLANET-B The detector (PLANET B Mars Dust Counter), which is an improved version of the Munich Dust Counters of HITEN and BREMSAT, will weigh only 630g with an aperture area 140cm2. The detectable mass range will be between 10-16g and more than 10-6g and the velocity range will be from 1km/s to more than 70km/s. Since PLANET-B executes retrograde elliptic orbits close to the zodiacal plane, our detector can investigate the spatial distribution of prograde dust particles from Phobos and Deimos with relative encounter velocity as large as or higher than 1km/s. PLANET-B MDC shall also measure the dust environment around the Earth and interplanetary and possibly interstellar dust particles.

Micrometeoroids of cometary or asteroidal origin constitute a unique repository of information concerning the formation and subsequent processing history of materials in the solar nebula. One of the current goals of planetary science is to return samples from a known primitive extraterrestrial body for detailed laboratory analysis (NASA Solar System Exploration Committee, SSEC 1983). Planetary flyby orbital motions dictate that dust particles will approach the spacecraft at relative speeds up to tens of km/s. It has always been thought that these hypervelocity particles could not be captured without melting or vaporizing. We have developed the intact capture technology that enables flyby sample return of these hypervelocity particles. The STARDUST comet sample return mission, selected as the fourth NASA. Discovery mission, capitalizes on this technology (Brownlee et al. 1996).

We are constructing a collector for capturing Interplanetary Dust Particles (IDPs) and space debris on space shuttle. The unit consists of three pieces of thin polyester film, equally spaced 7 cm apart, and an aerogel disk of 3 cm thickness. For each particle captured in the aerogel disk, we determine its direction of impact and its speed, from which we can trace its trajectory. The purpose of the experiment is to study the compositions of IDPs from different origins.

The conceptual design for an optical instrument capable of characterizing dust particles by in situ measurements is described. This instrument, the Integrated Dust Analyzer (IDA), measures the light scattered at several different angles as a particle passes through a pair of polarized light curtains. It is capable of defining or providing an indication of such characteristics as size, index of refraction, absorptivity, and aggregate structure.

A VELOCITY/TRAJECTORY cosmic dust sensor of the CHARGE-SENSING type was tested at the Heidelberg dust accelerator facility, using micronsized particles. The full-scale (0.4m x 0.4m x 0.3m) model displayed capabilities for providing accuracies to 0.1% in speed and 0.1° in angle relative to the spacecraft at high signal-to-noise (SNR) ratios. The particle's trajectory within the sensor can be located with an accuracy of 0.3mm.

We have studied several optical systems for dust velocity measurements on a cometary orbiter using light scattering to detect particles. Two main concepts are considered. The first relies on trajectory imaging, while the second uses time-of-flight measurements between two or more light sheets. Their merits and disadvantages are discussed. The favored system, time-of-flight between two planes with particle localization, is described.

Analyses of recovered samples of interplanetary dust have provided direct data on the bulk elemental composition of interplanetary dust over the 5μm to 1mm size range. The majority of particles have compositions similar to the bulk composition of chondrites although C and some trace volatile elements are often found in excess of CI abundances. Some individual particles have distinctly non-chondritic compositions. In most cases these particles contain large mineral grains.

Micrometeorites (MMs) represent the most common interplanetary dust particles (50-500 μm). They are similar to carbonaceous chondrites (CCs) but do not match, mineralogically and chemically, known CC types.

Amorphous silicate grains known as GEMS have been found in chondritic porous interplanetary dust particles (IDPs) from comets. GEMS are composed of nanometer-sized FeNi metal and Fe-rich sulfide crystals embedded in silicate glass. The properties of GEMS appear to have been shaped primarily by exposure to ionizing radiation and, since the irradiation occurred prior to accretion of the cometary IDPs, GEMS may have formed either in the solar nebula or presolar interstellar environments. The sizes, shapes, structures, and compositions of GEMS correspond to those of interstellar “amorphous silicate” grains. Nanometer-sized superparamagnetic metal inclusions dispersed throughout GEMS provide a logical explanation for alignment of interstellar silicate grains in the galactic magnetic field. Irrespective of their origins, GEMS are an important class of submicrometersized chondritic objects. If they were formed in the solar nebula, then they are among the oldest known solar nebula solids. If they are presolar, then they are probably examples of the “amorphous silicate” grains which are ubiquitous throughout the interstellar medium.

Over 100 individual and cluster interplanetary dust particles (IDPs) have been analyzed for bulk abundances of 15 elements (C, O, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, Fe, Ni). In general, IDPs have chondritic major element abundances, within a factor of 2 of the CI chondrites, and have carbon contents which average ~2-3 times higher than that of the most primitive, carbon-rich, carbonaceous meteorites (CI). The C-rich material is largely amorphous and is distributed throughout the particle as a matrix surrounding individual grains. The carbonaceous material has either smooth or vesicular texture; the latter texture suggests that volatiles could have been lost by particle heating which occurs during entry through the Earth's atmosphere.

Approximately 1/3 of interplanetary dust particles (IDPs) and some primitive meteorites have large excesses in D and/or 15N compared to terrestrial materials. Constraints on the nature and origin of the carriers of these isotopic anomalies are reviewed. Special attention is given to a recently discovered extremely D-rich cluster IDP.

The abundances of Ni, Fe, Cr, Mn, P, Cu, K, Na, Ga, Ge, Se, Zn, S, Br, and C were measured in interplanetary dust particles (IDPs) collected from the Earth's stratosphere. All elements with nebular condensation temperatures lower than Mn, except S, were enriched relative to the most volatile-rich type of meteorite while the refractory elements Cr and Ni were present at chondritic abundances. This element abundance pattern is consistent with nebular condensation, suggesting the IDPs condensed at either a different location or time in the evolving solar nebula than do the meteorites. The enrichments of the major elements C, Na, P, and K exclude the possibility that the volatile enrichment in IDPs results from a minor amount of contamination.