Apollo Lunar Surface
Experiment Package (ALSEP)
Heat Flow Experiment (HFE)
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Closeup of one of the two HFE probes from Apollo 17,
the only fully succesful deployment of this experiment in the program (full
image is below)
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Left - full image from which the closeup above was obtained,
with the Apollo 17 ALSEP in the background
Right - Apollo 15 crewman (Scott?) using the probe
rammer
to implant a heat flow probe into drill bore stem. Difficulties with the
drill caused this deployment to be only marginally successful
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Above - schematic diagrams of the components and layout
of the HFE
Apollo Experiment Number: S 037
Apollo Missions: 15, 16, 17
Wt: 9.9 kg (electronics box 4.6
kg)
Dim: Probes (2 ea) - 4 x 50 cm sections)
Electronics box - 28 x 25 x 24 cm
This experiment was designed to measure heat flowing
from the interior of the moon, which it was hoped would supply vital information
about the radioactive substances deep in the moon's core and possibly the
thermal history of the moon. It was considered one of the most important
ALSEP experiments, but the deployment problems that occurred with the hardware
gave the astronauts and the principal investigators of the experiment fits!
On Apollo 15, problems with the drilling equipment were
so bad that David Scott was able to get the probes only halfway to their
desired depth of 3 meters (~10 ft). On Apollo 16, after successfully drilling
the first hole and emplacing a probe into it, John Young caught one of
the cables for the experiment on his boot and yanked it out of its' connector
on the Central Station, effectively terminating the experiment for that
flight. Finally, Gene Cernan on A 17 was able to perform the only fully
successful deployment of this device.
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