Each new set of ground or space-based measurements obtained provides the mission team with additional opportunities to exercise how we will eventually adapt our plans to the Psyche we encounter upon arrival. Prelaunch simulations of the credible extremes of all physical parameters are conducted to confirm the viability of the operations plan.
( 2018a).Īpplying lessons learned from the Dawn mission (Polanskey et al., 2018b), the Psyche mission profile incorporates increased margins in operations duration, data volume, and onboard data storage capacity, providing a more robust operations environment and greater adaptability to unanticipated aspects of Psyche's physical characteristics. For more information about the instruments on the Psyche mission, please see Hart et al.
The mission was designed to allow all instruments to participate together in each science orbit, and the instrument data will be enhanced with a gravity investigation using the spacecraft itself and its X-band radio communications system. A gamma-ray and neutron spectrometer to determine elemental composition.Redundant multispectral imagers with eight filters to map composition and geomorphology and.Dual fluxgate magnetometers mounted on a 2-m boom in a gradiometer configuration, designed to search for evidence of remanent magnetization.
#Preflight phoenix full
A series of four circular orbits at progressively lower altitudes are used (Orbits A through D) to investigate Psyche with increasing resolution by the full instrument suite (Figure 1). The Psyche mission leverages the recent experience of the Dawn mission to develop strategies for thoroughly mapping and investigating a new solar system object while adjusting to Psyche's actual physical parameters as they are refined during the orbital operations phase. While information about the asteroid will continue to accumulate during the mission planning stage, the mission itself is flexible enough to adjust for changing expectations based on the most recent observing data. However, key characteristics needed to constrain Psyche's origins and evolution, particularly surface and bulk composition, remain poorly known. Recent ground observations of asteroid Psyche provide sufficiently mature and consistent shape and size estimates to support trajectory, orbit, and observation planning (Drummond et al., 2018 Shepard et al., 2017 Viikinkoski et al., 2018). Earth-based observations of (16) Psyche and other asteroids (henceforth, in this paper, we will omit the designator (16)), along with the library of meteorites available on Earth, form the basis for this exercise. Planning for the Psyche mission requires anticipating what features, compositions, and textures the asteroid might have and then further preparing for how those characteristics might be reflected in the eventual mission data. Despite the range of compositions and formation processes for Psyche allowed by the current data, the science payload of the Psyche mission (magnetometers, multispectral imagers, neutron spectrometer, and a gamma-ray spectrometer) will produce data sets that distinguish among the models. Final answers, as well as resolution of contradictions in the data set of Psyche physical properties, for example, the thermal inertia measurements, may not be resolved until the NASA Psyche mission arrives in orbit at the asteroid. CB chondrites match both Psyche's density and spectral properties, as can some pallasites, although typical pallasitic olivine contains too much iron to be consistent with the reflectance spectra. Though their density is similar, mesosiderites are an unlikely analog to bulk Psyche because mesosiderites have far more iron-rich silicates than Psyche appears to have. Psyche is thus predicted to have between ~30 and ~60 vol% metal, with the remainder likely low-iron silicate rock and not more than ~20% porosity.
Psyche's bulk density appears to be between 3,400 and 4,100 kg m −3. Here we combine observations of Psyche with data from meteorites and models for planetesimal formation to produce the best current hypotheses for Psyche's properties and provenance. New data on density, radar properties, and spectral signatures indicate that the asteroid is something perhaps even more enigmatic: a mixed metal and silicate world. Some years ago, the consensus was that asteroid (16) Psyche was almost entirely metal.
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