# The Distance between Two Points on Mars

The location of the InSight lander will be determined when it touches down in terms of its martian latitude and longitude. A marsquake or the impact of a meteor will occur at some other spot on Mars, also given by its latitude and longitude. This program calculates how far apart these two spots are from each other by setting their latitudes and longitudes.

Drag the impact/marsquake site on the Mars map. The box below the map shows the latitudes, longitudes, and calculated distance. You can also set latitudes and longitudes by editing the "distance computation code" below.

Distance between lander ($L$) and impact site ($I$):

$d = D \cos^{-1}(\sin(L_y)\sin(I_y) + \cos(L_y)\cos(I_y)\cos(I_x-L_x))$ =

where
• $D$ = 3390 km
• $(L_x, L_y)$ = longitude/latitude of lander = (, )
• $(I_x, I_y)$ = longitude/latitude of impact site = (, )

Distance computation code

GitHub source

More Space Math modules

This web page is adapted from Space Math @ NASA ILabs.

Background image taken by Mars Reconnaissance Orbiter
HiRISe camera on March 2010