The Psyche Magnetometry Investigation

Abstract

The objective of the Psyche Magnetometry Investigation is to test the hypothesis that asteroid (16) Psyche formed from the core of a differentiated planetesimal. To address this, the Psyche Magnetometer will measure the magnetic field around the asteroid to search for evidence of remanent magnetization. Paleomagnetic measurements of meteorites and dynamo theory indicate that a diversity of planetesimals once generated dynamo magnetic fields in their metallic cores. Likewise, the detection of a strong magnetic moment ($>2\times10^{14}~\text{Am}^{2}$ > 2 × 10 14 Am 2 ) at Psyche would likely indicate that the body once generated a core dynamo, implying that it formed by igneous differentiation. The Psyche Magnetometer consists of two three-axis fluxgate Sensor Units (SUs) mounted 0.7 m apart along a 2.15-m long boom and connected to two Electronics Units (EUs) located within the spacecraft bus. The Magnetometer samples at up to 50 Hz, has a range of $\pm80{,}000~\text{nT}$ ± 80 , 000 nT , and an instrument noise of $39~\text{pT}\,\text{axis}^{-1}\,3\sigma $ 39 pT axis − 1 3 σ integrated over 0.1 to 1 Hz. The two pairs of SUs and EUs provide redundancy and enable gradiometry measurements to suppress noise from flight system magnetic fields. The Magnetometer will be powered on soon after launch and acquire data for the full duration of the mission. The ground data system processes the Magnetometer measurements to obtain an estimate of Psyche’s dipole moment.

A Post‐Launch Summary of the Science of NASA's Psyche Mission

“…Such a measurement would likely be the best evidence that Psyche is a planetary core. The Magnetometry Investigation was designed to be able to detect the field of such a dipole moment from orbit in the face of solar wind variations and spacecraft and sensor noise (Elkins‐Tanton et al., 2020; Oran et al., 2022; Weiss et al., 2023). Nevertheless, the absence of a measurable magnetic field would not disprove that Psyche is a metal core.…”

“…The Magnetometer is composed of two three‐axis fluxgate Sensor Units mounted 0.7 m apart along a 2.15‐m long boom and connected to two Electronics Units located within the spacecraft bus (Weiss et al., 2023). This configuration provides redundancy and allows for removal of magnetic field contributions from the spacecraft to detect fields from any remanent magnetization.…”

Magnetic Field Modeling and Visualization of the Europa Clipper Spacecraft

“…This approached was also used to simulate the field lines of the Psyche spacecraft (Weiss et al. 2023 ).

Fig.

…”

“…2007 , Weiss et al. 2023 ). Each of these dipole moments has been extracted from magnetic field measurements made by the Europa Clipper project, provided by vendor document specifications or subject matter experts, or inferred from heritage part designs.…”

Moment of Inertia and Tectonic Record of Asteroid 16 Psyche May Reveal Interior Structure and Core Solidification Processes

“…Although the MOI cannot provide a unique solution for the radial density structure of a body, it can be used to estimate the level of differentiation of a body or to distinguish between plausible scenarios for interior structure. In particular, this MOI data can serve as a useful complement to the Psyche mission's magnetometer investigation, which should detect outer core magnetization if inward core growth occurred (Weiss et al, 2023). Therefore, the difference between inward and outward core growth should be detectable in the data acquired by the Psyche spacecraft.…”