##  It's very likely that inhabitants of either [Mataiva][1] or [Teti'aroa][2] were the ones !  
Now that one of the other answers has ruled out any Apollo astronaut, we can focus on determining the exact location on Earth, and this can be done with the aid of the [HORIZONS Web-Interface][3].  
With the **Table Settings** Quantities 1 and 15, the **Target Body** Earth and the **Observer Location** Sun(body center) we can see the Sunsub longitude and the Sunsub latitude at the beginning of August 27, 2003.  
Averaging for 9.51 UTC gives a longitude of 330.26405⁰ and a latitude of 10.210355⁰ for the place where the Sun would be in the zenith.  
Comparing this table with one with Mars as the **Target Body** we see that the [right ascension][4] for Earth and Mars are almost equal at that special time, so the plane that contains the Sun, Earth and Mars was then almost perpendicular to the ecliptic.(and the angles of declination of the two planets would lie in that plane.)  
If the Earth and Mars had also the same [declination][5] at that time, we just could draw a line from the "Sunsub" spot on Earth through its centre to the surface on the other side where Mars would then be in the zenith.(supposing the Earth would be a perfect sphere).  
That "midnight spot" would then have coordinates 150.264⁰ West and 10.210355⁰ South.  
But when we look at still another table with **Target Body** Mars but with this time **Observation Location** "Geocentric" at August 27, 2003, Mars has a considerable declination of over -15⁾, minus the declination of Earth of -10⁾ 9', and then averaged to -5⁰,35' for 9.51 UTC.  

**That makes the final coordinates of the closest spot to Mars: 150⁰ 16'W, 15⁰ 47'S.**   
(somewhere between [Mataiva][1] and [Teti'aroa][2])



[1]: https://en.wikipedia.org/wiki/Mataiva
[2]: https://en.wikipedia.org/wiki/Teti'aroa
[3]: https://ssd.jpl.nasa.gov/horizons.cgi#results
[4]: https://en.wikipedia.org/wiki/Right_ascension
[5]: https://en.wikipedia.org/wiki/Declination