Here is the story behind the convertion what is coming from the sources although officially it is not declared so far. When the astronauts were taking photographs of earth from the space satellite with the help of powerful telescope they found the complete earth as dark except the two places on the earth i.e Mecca and Madinah, two famous historically rich cities of Saudi Arabia.
The pictures of Mecca and Madinah from satellite is given below. It looks very interesting and nothing but miracle. Although the acceptance of Islam by Sunita Williams is not so far confirmed by any authenticated source but the pictures they took from satellite was very interesting and definitely a miracle.
Satellite Pictures of Mecca and Madinah of Saudi Arabia from Satellite by Sunita Williams.
p/s: Masyaalah.. Allah S.W.T is so great. Dear brothers n sisters, we do surely be proud to be muslim.