2018-06-25. The Case of the Missing Lunar Heat Flow Data Is Finally Solved.

posted Jul 2, 2018, 2:52 PM by Alan Gould   [ updated Jul 2, 2018, 2:52 PM ]
By Sarah Stanley, Eos/AGU. For GSS A Changing Cosmos chapter 7. Excerpt: Decades-old data analyzed for the first time suggest that astronauts’ disturbance of the Moon surface increased solar heat intake, warming the ground below. During the Apollo 15 and 17 missions, astronauts installed four temperature-sensing probes in shallow, 1.0- to 2.4-meter-deep holes drilled into the Moon. They aimed to measure how much of the Moon’s heat was lost to space, which could provide insights into the origin and the differentiation history of the Moon. The Apollo Heat Flow Experiment ran from 1971 to 1977. ...In 2011, the researchers reported that they had found about 10% of the missing tapes at the Washington National Records Center in Maryland. ...They found that from 1974 until the Heat Flow Experiment concluded in 1977, the lunar subsurface warmed up, with greater warming occurring at shallower depths. This continued a warming trend observed by the original researchers in data collected between 1971 and December of 1974. The measurements indicate that the observed warming began near the surface and spread downward. ...Calculations from heat conduction models suggest that the timing and amount of warming seen at different depths are best explained by a rapid increase in surface temperature at the time of probe installation. This finding supports the hypothesis that disturbance of the lunar surface by astronauts’ footprints and other activities increased its roughness, reducing the amount of solar radiation reflected back to space. Thus, increased absorption of solar heat caused the observed warming.... https://eos.org/research-spotlights/the-case-of-the-missing-lunar-heat-flow-data-is-finally-solved