NASA said on Thursday that when its Lunar Reconnaissance Orbiter (LRO) passed over Vikram's landing site on September 17 and took high resolution images of the area it was dusk "and thus large shadows covered much of the terrain."
"It is possible that the Vikram lander is hiding in a shadow," NASA said.
It said that it will make another attempt to locate Vikram next month when the lighting will be favourable.
NASA released pictures taken by the LROC of the area around the moon's South Pole where Vikram could have landed after it lost contact with the Indian Space Research Organisation following its launch by the Chandraayan 2 moon orbiter on September 6.
The main image covered an area of 150 kilometres and long dark shadows loomed in many places in the picture.
LRO project scientist at NASA's Goddard Space Flight Center, Noah Petro, had told a day after the pictures were taken, "It is important to remember that the illumination conditions right now where the lander may be are harsh" and it may be difficult to locate it.
He said the LRO is scheduled to pass over the site on October 14.
(Arul Louis can be contacted at arul.l@.in and followed on Twitter @arulouis)
( With inputs from IANS )