Heat Flow Experiment
.jpg?lang=en) The Apollo 17 Heat Flow Experiment on the Moon | |
| Acronym | HFE |
|---|---|
| Notable experiments | Apollo 16 & 17 |
The Heat Flow Experiment was a lunar science experiment that aimed to measure the rate of heat loss at the surface of the moon. Four experiments were carried on board Apollo missions. Two experiments were successfully deployed as part of Apollo 15 and Apollo 17. The instrument on Apollo 16 was deployed but the cable from it to the ALSEP central station was broken and the experiment was rendered inoperable. A heat flow experiment was carried on board Apollo 13 but the mission was aborted in-flight and the instrument never reached the surface.[1]
Background
Establishing some of the thermal properties of the moon's surface was already feasible by the time of the Apollo missions. Measuring of infrared emissions via telescope and the measuring of microwave emission spectra from the the moon was already possible from the surface of the earth. [2] These already has established some of characteristic of the moon's surface including temperature, thermal conductivity and heat capacity.[1] The degree to which these properties were limited by the low levels of IR emission, long wavelengths limiting data resolution, and how the moons thermal properties vary with depth.[1]
No one person can be attributed with the proposal to measure heat flow from the moon given the large number of proposals NASA sought from academia, industry and from science groups at NASA itself. Several of these proposed such an experiment.[1] The result though was that a small committee was formed to explore how thermal measurements of the moon could be taken.[1] The committee decided that the focus of any thermal experiment should be focused on heat flow from the moon's interior.[1]
The committee considered a number of approaches that included multiple probes and another that included "blankets". The blanket technique was initially ruled out due to the complexity of matching the thermal albedo of the blanket probes with that of the moon's surface.[1] The method settled on that become the basis for the instrument was a cylindrical heater paired with a temperature sensor a set distance away. [1]
Instrument
Missions
On Apollo 16 the holes for the probes were dug by Charles Duke who managed to drill down to 3 meters bellow the surface.[3] The experiment came to an end before it started when John Young managed to damage the cables after getting them wrapped about his feet.[3] Repairing was considered but rejected due to it needing several hours of surface time.[3]
Science
References
- ^ a b c d e f g h Langseth, M. G. (1977). "Lunar heat-flow experiment". NASA.
- ^ Clark, S. P. (1965). "Some calculations pertaining to the feasibility of measuring lunar heat flow Final report". NASA.
- ^ a b c Ulivi, Paolo; Harland, David Michael (2004). Lunar Exploration: Human Pioneers and Robotic Surveyors. Springer-praxs. p. 172. ISBN 91-85233-746-x.
{{cite book}}: Check|isbn=value: invalid character (help)