Geology topics

Christopher P McKay

Publications and source records attributed to Christopher P McKay.

3 recordsLinked to original sources

USGS2011

The case for planetary sample return missions

The essential role of planetary sample studies in exploration of the solar system has been well established “Drake et al., 1987”. As part of the larger pursuit of comparative planetology, samples of other rocky planets (Mercury, Venus, Mars), planetary satellites, asteroids, and comets should reveal much about the materials and processes that formed Earth. In that context, Mars is an especially appealing sample target because of its distinctive, Earth‐like characteristics. Here, we review the scientific objectives and justifications for collecting documented samples of Mars and returning them to Earth for laboratory study. A Mars sample‐return mission will be technologically challenging but represents the only way to acquire definitive knowledge about formation of the planet, its geologic and climatic history, and its potential as a haven of life.

Eos, Transactions, American Geophysical Union↗

USGS2010

NASA's explorer school and spaceward bound programs: Insights into two education programs designed to heighten public support for space science initiatives

Introduction NASA has played an influential role in bringing the enthusiasm of space science to schools across the United States since the 1980s. The evolution of this public outreach has led to a variety of NASA funded education programs designed to promote student interest in science, technology, engineering, math, and geography (STEM-G) careers. Purpose This paper investigates the educational outreach initiatives, structure, and impact of two of NASA's largest educational programs: the NASA Explorer School (NES) and NASA Spaceward Bound programs. Results Since its induction in 2003 the NES program has networked and provided resources to over 300 schools across the United States. Future directions include further development of mentor schools for each new NES school selected, while also developing a longitudinal student tracking system for NES students to monitor their future involvement in STEM-G careers. The Spaceward Bound program, now in its third year of teacher outreach, is looking to further expand its teacher network and scientific collaboration efforts, while building on its teacher mentorship framework.

Acta Astronautica↗

USGS2007

Rainfall limit of the N cycle on Earth

In most climates on Earth, biological processes control soil N. In the Atacama Desert of Chile, aridity severely limits biology, and soils accumulate atmospheric NO 3 − . We examined this apparent transformation of the soil N cycle using a series of ancient Atacama Desert soils (>2 My) that vary in rainfall (21 to <2 mm yr −1 ). With decreasing rainfall, soil organic C decreases to 0.3 kg C m −2 and biological activity becomes minimal, while soil NO 3 − and organic N increase to 4 kg N m −2 and 1.4 kg N m −2 , respectively. Atmospheric NO 3 − (Δ 17 O = 23.0‰) increases from 39% to 80% of total soil NO 3 − as rainfall decreases. These soils capture the transition from a steady state, biologically mediated soil N cycle to a dominantly abiotic, transient state of slowly accumulating atmospheric N. This transition suggests that oxidized soil N may be present in an even more arid and abiotic environment: Mars.

Global Biogeochemical Cycles↗