Figure S1.

Minimum height above topography reached for the GRAIL spacecraft in units
of km for the GRAIL extended mission (August 30 -- December 14, 2012).
The minimum height was computed with respect to a grid derived
from the data obtained from the Lunar Orbiter Laser Altimeter
(LOLA) of the Lunar Reconnaissance Orbiter (LRO) (Smith et al., 2010).