Lunar Heat Flow Probe, Phase I

Metadata Updated: May 2, 2019

To accurately determine endogenic heat flow, both thermal gradient and thermal conductivity measurements are needed. The thermal gradient measurement can be achieved by using several temperature sensors equally spaced along the length of the probe. Thermal conductivity can be measured by one of two methods: the 'steady state' method or the 'transient with a variant' or 'pulse heating' method. The steady state method was used by the Apollo 15-17 missions , whereas the pulse heating method was developed by Lister (1979) after the Apollo period In the steady state heating method, heat is applied to the regolith around the probe for a long period of time and thermal conductivity is derived from the rate at which temperature rises. This will affect the measurement associated with the diurnal and annual wave as it adds a significant amount of heat to the regolith, which will take a very long time to dissipate. In the pulse heating method, more heat is applied for a short duration of time. The temperature of the probe increases instantaneously and slowly falls off as the heat dissipates into the regolith after the heater is turned off. In this case, the thermal conductivity is derived from the cooling rate. In the pulse heating method, less heat is required and less time is required for a measurement. For the most accurate results, sensors must extend below the depth of the multi-year thermal fluctuation detected during the Apollo missions (>3 m). If the hole is deep enough to avoid the effects of the insolation, the geothermal gradient obtained in a lower portion of the hole should accurately reflect the endogenic heat flow. The spacing between sensors should be small (approximately 30 cm), because thermal conductivity of the regolith is heavily affected by its texture, which varies with depth. Determining the in situ heat flow, as well as the site-specific thermal wave depths, requires that measurements be taken over long durations (6-8 years).

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Public: This dataset is intended for public access and use. License: U.S. Government Work

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Metadata Created Date August 1, 2018
Metadata Updated Date May 2, 2019

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date August 1, 2018
Metadata Updated Date May 2, 2019
Publisher Space Technology Mission Directorate
Unique Identifier TECHPORT_33544
Maintainer Email
Public Access Level public
Bureau Code 026:00
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Datagov Dedupe Retained 20190501230127
Harvest Object Id c7ed49a1-5ad4-4e21-bd94-8329c5567ade
Harvest Source Id 39e4ad2a-47ca-4507-8258-852babd0fd99
Harvest Source Title NASA Data.json
Data First Published 2015-12-01
Homepage URL
Data Last Modified 2018-07-19
Program Code 026:027
Source Datajson Identifier True
Source Hash 25097fd71779e4b0b751b1b8cfb064747d463f3f
Source Schema Version 1.1

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