Washington, July 18 - There are still many secrets waiting to be gleaned from moon rocks collected by Apollo 11 astronauts on their historic moonwalk 40 years ago.

Randy L Korotev, research professor in the department of earth and planetary sciences Washington University-St Louis (WUSTL), has studied lunar samples and their chemical compositions since he was an undergraduate at the University of Wisconsin.

He 'was in the right place at the right time' in 1969 to be a part of a team to study some of the first lunar samples. 'We know even more now and can ask smarter questions as we research these samples,' says Korotev.

He is mainly interested in studying the impact history of the moon, how the moon's surface has been affected by meteorite impacts and the nature of the early lunar crust.

'There are still some answers, we believe, in the Apollo 11 mission. It's only been fairly recently that we decided that we should look closer at these Apollo 11 samples.'

Korotev credits the late Robert M. Walker, Washington University's physics professor and a handful of other scientists for the fact that there are even moon samples to study.