The State and Future of Mars Polar Science and Exploration

Abstract

20, 1999; revised October 25, 1999 As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of -lo6 km2 and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young-preserving a record of the seasonal and climatic cycling of atmospheric COz, H20, and dust over the past NIO~-IO~ years..For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet--documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason-providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.

The construction of Chasma Boreale on Mars

“…The polar layered deposits of Mars contain the planet's largest known reservoir of water ice 1,2 and the prospect of revealing a detailed Martian palaeoclimate record 3,4 , but the mechanisms responsible for the formation of the dominant features of the north polar layered deposits (NPLD) are unclear, despite decades of debate. Stratigraphic analyses of the exposed portions of Chasma Boreale-a large canyon 500 km long, up to 100 km wide, and nearly 2 km deep-have led most researchers to favour an erosional process for its formation following initial NPLD accumulation.…”

Experimental and theoretical simulation of sublimating dusty water ice with implications for D/H ratios of water ice on Comets and Mars

“…[49][50][51], to contain a great deal of dusty material. The polar caps of Mars are also known to be rich in dust [52] with up to 6% by weight on the surface, as determined by the OMEGA instrument on Mars Express [53] and potentially more at depth.…”

Introduction to the 4th Mars Polar Science and Exploration Conference special issue: Five top questions in Mars polar science

“…Atmospheric dust raised from the surface by dust storms is thought to act as condensation nuclei for the water vapor and atmospheric CO 2 (Kieffer and Titus, 2001). In autumn, H 2 O and CO 2 condense on the dust particles and precipitate to the surface (reviewed in Clifford et al, 2000a). H 2 O and CO 2 frost may also condense directly on the surface or in pores in the near-subsurface depending on temperature and air humidity (Schorghofer and Aharonson, 2005).…”

“…The purpose of this paper is to highlight key unresolved questions and needed observations as a proposed guideline to future Mars polar science and exploration, rather than to provide a comprehensive review of the state of knowledge of the field. However, we do briefly concentrate on advances since the 3rd conference and since the review provided in Clifford et al (2000a).…”