Within the young solar system, a strong magnetic field permeated the protoplanetary disc. The solar nebular magnetic field is likely the source of magnetization for some meteorites like the CM and CV chondrites, which underwent aqueous alternation on their parent bodies before the solar nebular field dissipated. Since aqueous alteration produced magnetic minerals (e.g. magnetite and pyrrhotite), the meteorites could have acquired a chemical remanent magnetization from the nebular field while part of their respective parent bodies. However, questions about the formation history of the parent bodies that produced magnetized CM and CV chondrites await answers—including whether the parent bodies exhibit a detectable magnetic field today. Here, we use thermal evolution models to show that a parent body of the CM chondrites could record ancient magnetic fields and, perhaps, exhibit strong present-day crustal remanent fields. An undisturbed planetesimal would experience one of three thermal evolution cases with respect to the lifetime of the nebular field. First, if a planetesimal formed too late for 26Al-driven water ice melting to occur before the solar nebula dissipates, then aqueous alteration would not occur in the presence of the nebular field and result in no magnetization (Fig. panel a). Second, if a planetesimal forms early enough to undergo alteration before the nebula dissipates but not enough to heat beyond the blocking temperature(s) of the magnetic mineral(s), then nearly the entire planetesimal could be magnetized (Fig. panel b). Lastly, if a planetesimal forms early enough to undergo alteration and subsequently heats beyond the blocking temperature, then any magnetization would be erased except for a thin shell near the surface (Fig. panel c). Our thermal model results suggest that planetesimals that formed between ~2.7 and 3.7 Myr after CAIs could acquire large-scale magnetization. Spacecraft missions could detect this magnetization if it is at the strength recorded in CM chondrites and if it is coherent at scales of tens of kilometers. In-situ magnetometer measurements of chondritic asteroids could help link magnetized asteroids to magnetized meteorites. Specifically, a spacecraft detection of remanent magnetization at 2 Pallas would bolster the claim that 2 Pallas is a parent body of CM chondrites.

One of the next giant leaps for humanity—inhabiting our neighbor planet Mars—requires enough water to support multi-year human survival and to create rocket fuel for the nearly 150-million-mile return trip to Earth. Water that is already on Mars, in the form of ice, is one of the leading in situ resources being considered in preparation for human exploration. Human missions will need to land in locations with relatively warm temperatures and consistent sunlight. But in these locations, ice (if present) is buried underground. Much of the ice known to exist in mid-latitude locations was likely emplaced under climate conditions (and orbital parameters) different from today. So in addition to providing an in-situ resource for human exploration, Martian ice also provides a crucial record of planetary climate change and the effects of orbital forcing.This presentation will highlight techniques and recent activities to characterize Mars’ underground ice, such as the Subsurface Water Ice Mapping (SWIM) Project (Morgan et al. 2021, Nature Astro.; Putzig et al. In Press, Handbook of Space Resources; Putzig et al. this AGU; Morgan et al. this AGU). We present outstanding questions that will be vital to address in the context of ISRU (in situ resource utilization) and connections between these questions and the climate in which the ice was emplaced and evolved (e.g., Bramson et al. 2020, Decadal White Paper). Lastly, we discuss how these science activities intersect with future exploration, particularly that enabled by collaborations between space agencies as well as industry partners (Heldmann et al. 2020, Decadal White Paper; Golombek et al. 2021, LPSC).High-priority future work includes better orbital characterization of shallow ice deposits, such as radar sounding at shallower scales (<~10m) than that of SHARAD, as proposed for the International Mars Ice Mapper. Also needed are detailed studies of the engineering required to build potential settlements at specific candidate locations; this includes characterization of the nature of the overburden above the ice, which will inform future resource extraction technology development efforts. Ideally, initial landing sites would be chosen with a long-term vision which includes preparation and development of the basic technologies and designs needed for human landing on Mars.