Priorities are described for research on trans-Neptunian Objects (TNOs), a recently-discovered (t... more Priorities are described for research on trans-Neptunian Objects (TNOs), a recently-discovered (thereby excluding Pluto and Charon) population of small, outer solar system objects with important implications for the early history of the solar system. We conclude that we must discover and obtain accurate orbits for an unbiased sample of ~5000 TNOs over the next decade and a significant fraction of these objects must be targeted for more detailed physical observations. A broad range of complementary theoretical and laboratory studies are also needed, and we must work towards direct spacecraft exploration of TNOs as soon as possible.
Installed on peripheral plates of the Bepi Colombo MMO spacecraft, the Mercury Dust Monitor (MDM)... more Installed on peripheral plates of the Bepi Colombo MMO spacecraft, the Mercury Dust Monitor (MDM) is an array of light-weight, heat resistant, piezo-electric momentum sensor to determine incident timing, momentum, and crude incoming direction of hypervelocity impact micro particles around Mercury. It has two major scientific interest, flux and origin variations on interplanetary meteoroid complex inside 1 AU, as a function of the heliocentric distance and the first-ever in-situ investigation of the near-Mercury dust environment. Detector characteristics are 4 flat PZT, each size is 5cmx5cm and 1mm thick. The weight of this PZT detector is about 0.1 kg. The shape of impact signals are measured by a digital circuit with about several 10 MHz A/D converter. Through the shape of signals, we can know rough speed of the impact particles and also can separate the real impact signals from the noise signals. The weight of this circuit, include box and connector is about 0.4 kg and nominal pow...
Space weather including solar activity and background plasma sets up spacecraft conditions that c... more Space weather including solar activity and background plasma sets up spacecraft conditions that can magnify the threat from hypervelocity impacts. Hypervelocity impactors include both meteoroids, traveling between 11 and 72 km/s, and orbital debris, with typical impact speeds of 10 km/s. When an impactor encounters a spacecraft, its kinetic energy is converted over a very short timescale into energy of vaporization and ionization, resulting in a small, dense plasma. This plasma can produce radio frequency (RF) emission, causing electrical anomalies within the spacecraft. In order to study this phenomenon, we conducted ground-based experiments to study hypervelocity impact plasmas using a Van de Graaff dust accelerator. Iron projectiles ranging from 10−16 g to 10−11 g were fired at speeds of up to 70 km/s into a variety of target materials under a range of surface charging conditions representative of space weather effects. Impact plasmas associated with bare metal targets as well as...
Priorities are described for research on trans-Neptunian Objects (TNOs), a recently-discovered (t... more Priorities are described for research on trans-Neptunian Objects (TNOs), a recently-discovered (thereby excluding Pluto and Charon) population of small, outer solar system objects with important implications for the early history of the solar system. We conclude that we must discover and obtain accurate orbits for an unbiased sample of ~5000 TNOs over the next decade and a significant fraction of these objects must be targeted for more detailed physical observations. A broad range of complementary theoretical and laboratory studies are also needed, and we must work towards direct spacecraft exploration of TNOs as soon as possible.
Installed on peripheral plates of the Bepi Colombo MMO spacecraft, the Mercury Dust Monitor (MDM)... more Installed on peripheral plates of the Bepi Colombo MMO spacecraft, the Mercury Dust Monitor (MDM) is an array of light-weight, heat resistant, piezo-electric momentum sensor to determine incident timing, momentum, and crude incoming direction of hypervelocity impact micro particles around Mercury. It has two major scientific interest, flux and origin variations on interplanetary meteoroid complex inside 1 AU, as a function of the heliocentric distance and the first-ever in-situ investigation of the near-Mercury dust environment. Detector characteristics are 4 flat PZT, each size is 5cmx5cm and 1mm thick. The weight of this PZT detector is about 0.1 kg. The shape of impact signals are measured by a digital circuit with about several 10 MHz A/D converter. Through the shape of signals, we can know rough speed of the impact particles and also can separate the real impact signals from the noise signals. The weight of this circuit, include box and connector is about 0.4 kg and nominal pow...
Space weather including solar activity and background plasma sets up spacecraft conditions that c... more Space weather including solar activity and background plasma sets up spacecraft conditions that can magnify the threat from hypervelocity impacts. Hypervelocity impactors include both meteoroids, traveling between 11 and 72 km/s, and orbital debris, with typical impact speeds of 10 km/s. When an impactor encounters a spacecraft, its kinetic energy is converted over a very short timescale into energy of vaporization and ionization, resulting in a small, dense plasma. This plasma can produce radio frequency (RF) emission, causing electrical anomalies within the spacecraft. In order to study this phenomenon, we conducted ground-based experiments to study hypervelocity impact plasmas using a Van de Graaff dust accelerator. Iron projectiles ranging from 10−16 g to 10−11 g were fired at speeds of up to 70 km/s into a variety of target materials under a range of surface charging conditions representative of space weather effects. Impact plasmas associated with bare metal targets as well as...
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