NASA never said this. Its images of 2002 show a chain of shoals between Pamban and Mannar, and NASA stated that photographs from orbit cannot tell the origin or age of such a chain. The Setu stands on the authority of the Ramayana, not on NASA.
The proof
- The "17,50,000-year-old man-made bridge" claim began with an Indian newspaper report of October 2002 built around NASA images; NASA disowned the reading.
- Valmiki Ramayana, Yuddha Kanda: Nala, son of Vishvakarma, built the setu with the vanara army, a hundred yojanas long and ten wide.
01Let the Ramayana speak for itself
Valmiki tells how the ocean god advised Shri Ram that Nala could bridge the sea, how the vanaras hauled rocks and trees, and how the setu was finished in five days, a line across the waves like the parting in a woman’s hair. For the devotee that is the authority, and Rameswaram, Dhanushkodi and Setu-bandha have been tirthas for that reason. A borrowed and false NASA stamp adds nothing to it and gives critics an easy target. Respect the Itihasa by quoting it, and quote NASA only for what NASA actually said.
Read on

Maharshi Valmiki
Valmiki is the Adi Kavi, the first poet, whose Ramayana of about 24,000 shlokas tells the life of Shri Rama. He was a contemporary of Rama, and Sita lived in his ashram where Lava and Kusha were born.

Ramanathaswamy Temple, Rameswaram
The southern Jyotirlinga, installed by Shri Rama on the island at the head of the setu before the war in Lanka. It is also the southern dham of the Char Dham.
