Apollo 13 Lunar Heat Flow Experiment

Langseth, Marcus G.; Wechsler, A. E.; Drake, Elisabeth M.; Simmons, Gene; Clark, Sydney P.; Chute, John L.

doi:10.1126/science.168.3928.211

Cited by 32 publications

(44 citation statements)

References 17 publications

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“…The probes were inserted into predrilled holes, which were fitted with a fiberglass borestem. [Langseth et al, 1973] as well as the attenuation of the annual temperature wave [Langseth et al, 1976]. For the calculation of thermal conductivities from thermal diffusivities a heat capacity of 670 J kg −1 K −1 has been assumed.…”

Section: Introductionmentioning

confidence: 99%

“…[2] Lunar heat flow has been measured at the Hadley Rille and Taurus-Littrow sites during the Apollo 15 and 17 missions and values of 21 and 16 mW m −2 have been obtained [Langseth et al, 1972a[Langseth et al, , 1972b[Langseth et al, , 1973[Langseth et al, , 1976. Uncertainties for these values are given at ±15%, which mainly stem from the uncertainty connected to the regolith's thermal conductivity, although no rigorous error analysis was presented.…”

Section: Introductionmentioning

confidence: 99%

“…[6] With this setup it was possible to estimate the thermophysical properties of the lunar regolith using four different methods [Langseth et al, 1972a[Langseth et al, , 1973: (1) active heating experiments were carried out by operating the heating elements as line heat sources; (2) the thermal reequilibration of the borestem was monitored as a function of time after initial insertion of the probes; (3) the decay of the periodic temperature perturbations induced by the annual temperature waves was analyzed as a function of depth; and (4) the propagation of Astronaut induced thermal disturbances was evaluated as a function of depth.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the temperature sensors, four active heating elements, which were operated like classical line heat sources [Langseth et al, 1972a[Langseth et al, , 1973, were placed on the outside of the probes. Names of the sensors in Figure 1 are given according to the following naming convention: The first letter designates the type of sensor, where T stands for resistance temperature detectors (as compared to TC for thermocouples).…”

Section: Introductionmentioning

confidence: 99%

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Apollo lunar heat flow experiment revisited: A critical reassessment of the in situ thermal conductivity determination

Grott¹,

Knollenberg²,

Krause³

2010

J. Geophys. Res.

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[1] Lunar heat flow was determined in situ during the Apollo 15 and 17 missions, but some uncertainty is connected to the value of the regolith's thermal conductivity, which enters as a linear factor into the heat flow calculation. Different approaches to determine the conductivity yielded discordant results, which led to a downward correction of the obtained heat flow values by 30%-50% subsequent to the publication of the first results. We have reinvestigated likely causes for the observed discrepancies and find that neither poor coupling between the probe and regolith nor axial heat loss can explain the obtained results. Rather, regolith compaction and compression likely caused a local increase of the regolith's thermal conductivity by a factor of 2-3 in a region which extends at least 2-5 cm from the borehole wall. We conclude that the corrected lunar heat flow values, which are based on thermal diffusivity estimates sampling a large portion of undisturbed regolith, represent robust results. Future in situ measurements of regolith thermal conductivity using active heating methods should take care to both minimize regolith disturbance during probe emplacement and maximize heating time to obtain reliable results. We find that for the Apollo measurements, heating times should have exceeded at least 100 h, and ideally 200 h.Citation: Grott, M., J. Knollenberg, and C. Krause (2010), Apollo lunar heat flow experiment revisited: A critical reassessment of the in situ thermal conductivity determination,

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Apollo lunar heat flow experiment revisited: A critical reassessment of the in situ thermal conductivity determination

Grott¹,

Knollenberg²,

Krause³

2010

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…Up to now they have only been performed successfully at two places on the Moon, in the frame of the Apollo 15 and 17 missions (Langseth et al 1972(Langseth et al , 1976. These pioneering in situ measurements showed that the uppermost layers of the lunar regolith have an extremely low thermal conductivity, which is probably caused by the loose packing and irregular shape of the lunar soil particles (Pilbeam and Vaisnys 1973).…”

Section: Introductionmentioning

confidence: 99%

Development of Thermal Sensors and Drilling Systems for Application on Lunar Lander Missions

et al. 2008

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The upcoming lunar lander missions, for example Chang'e 2 from CNSA and several mission proposals and studies currently under consideration at NASA (e.g. Neal et al., ROSES 2006 Proposal to NASA, 2006 Potsdam, Germany, 2007) and JAXA, Japan (Matsumoto et al., Acta Astronautica, 59:68-76, 2006) offer new possibilities to measure the thermal properties of the lunar regolith and to determine the global lunar heat flow more accurately than it is hitherto known. Both properties are of high importance for the understanding of the lunar structure and the evolution of the Moon-Earth system. In this paper we present some work on new thermal sensors to be used for in situ investigations of the lunar soil in combination with novel drilling techniques applicable for the lunar regolith. Such systems may preferably be mounted on mobile stations like the lunar rover currently built for the Chinese Chang'e 2 mission. A general description of a presently tested prototype of the lunar rover is given and mounting possibilities for a drilling system and thermal sensors are shown. Then we discuss some options for thermal sensors and drills and how they could be combined into one compact instrument. Subsequently a tube-like sensor suitable for measuring the thermal conductivity of the material surrounding a borehole 123Earth Moon Planet (2008) 103:119-141 DOI 10.1007 is described in more detail. Finally the performance of such a tube-shaped sensor when applied in a lunar borehole is investigated by thermal modelling and compared with the behaviour of a more conventional needle-shaped sensor.

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Predicting the Geothermal Heat Flux in Greenland: A Machine Learning Approach

Rezvanbehbahani

Stearns

Kadivar

et al. 2017

Geophysical Research Letters

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Geothermal heat flux (GHF) is a crucial boundary condition for making accurate predictions of ice sheet mass loss, yet it is poorly known in Greenland due to inaccessibility of the bedrock. Here we use a machine learning algorithm on a large collection of relevant geologic features and global GHF measurements and produce a GHF map of Greenland that we argue is within ∼15% accuracy. The main features of our predicted GHF map include a large region with high GHF in central-north Greenland surrounding the NorthGRIP ice core site, and hot spots in the Jakobshavn Isbrae catchment, upstream of Petermann Gletscher, and near the terminus of Nioghalvfjerdsfjorden glacier. Our model also captures the trajectory of Greenland movement over the Icelandic plume by predicting a stripe of elevated GHF in central-east Greenland. Finally, we show that our model can produce substantially more accurate predictions if additional measurements of GHF in Greenland are provided. Plain Language Summary The heat generated at the interior regions of Earth (geothermal heat flux, GHF) can be high enough to melt the bottom layers of ice sheets, decrease friction between ice and bedrock, and increase ice discharge to the ocean. This heat, however, cannot be directly measured in ice sheets because the bedrock is inaccessible. Here we present a novel approach to estimate this heat. We combine all the available geologic, tectonic, and GHF data that are available on all continents. We then establish a complex relationship between GHF and all the geologic-tectonic features using machine learning techniques and then predict the GHF for the Greenland Ice Sheet. We utilize all information from available ice cores and bedrock boreholes to improve the GHF prediction in Greenland. Thus, the new GHF map honors tectonic settings, regional geology, and measurements from ice cores and can be used as an important input parameter to numerical ice sheet models that aim at lowering the uncertainties of future sea level rise predictions. This study derives a new map of GHF for the GrIS using statistical relationships between global heat flux observations and the combined influence of local geology and regional tectonic setting. Compilations of global RESEARCH LETTER 10.1002/2017GL075661 Key Points: • A new geothermal heat flux map of Greenland is obtained within ∼15% accuracy using machine learning techniques • The new map honors regional geology, tectonic settings, and ice core measurements • Pockets of high heat flux are predicted in central-north Greenland and upstream of several fast-flowing outlet glaciers

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Apollo 13 Lunar Heat Flow Experiment

Cited by 32 publications

References 17 publications

Apollo lunar heat flow experiment revisited: A critical reassessment of the in situ thermal conductivity determination

Apollo lunar heat flow experiment revisited: A critical reassessment of the in situ thermal conductivity determination

Development of Thermal Sensors and Drilling Systems for Application on Lunar Lander Missions

Predicting the Geothermal Heat Flux in Greenland: A Machine Learning Approach

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