Transcript ARTEMIS for planetary slide_Khurana

Lunar Interior Magnetic Sounding
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Unanswered questions about the lunar interior
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Did the Moon form from a collision between a Mars size object and the
Earth? What was the impactor size? How much of the lunar material
came from the Earth and how much came from the impactor? How deep
and variable (in composition and depth) was the lunar magma ocean?
Does the Moon have a core? What is its size?
Electromagnetic induction studies from Apollo era surface and
spacecraft magnetometers support the lunar magma ocean
hypothesis but are ambiguous because of low signal/noise ratio.
Data from Lunar Prospector (see Figure 2, right, Hood et al. 1999,
GRL) is supportive of a lunar core (radius ~ 400 km) but the results
are marginal again because of the low signal/noise ratio of the data.
The unique two point simultaneous measurements from Artemis will
allow us to separate the external (inducing field) and internal (the
induction response) fields at a wide range of frequencies, uniquely
and accurately, resulting in a much higher signal/noise ratio.
The shorter periods (minute to tens of minutes) will provide
information on the crust and upper mantle of the moon, helping us
determine the location of the magma ocean boundary.
The longer periods (several hours) will provide information on the
size and conductivity of the lunar core (see Figure 1, right).
Only night side data will be used to minimize the compressional
effect of the solar wind on the induction field.
THM+ART Senior Review
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Hood et al. 1999,
GRL
Hood et al. 1999
June 13, 2008