Wang Yaping aboard China's space module Tiangong-1 gives a lecture about laws of physics. [Photo/Xinhua]

BEIJING - In China's first "space class", the country's second female astronaut in space Thursday says she and her crewmates haven't seen any UFOs during the space trip.

Female astronaut Wang Yaping, one of the three crew members of Shenzhou-10 spacecraft, greeted about 330 primary and middle school students at a Beijing high school, through a live video feed system, about 340 km above the Earth.

"Through the front windows, we can see the Earth and many other stars, but up till now, we haven't seen any UFOs,"Wang says.

"We are beyond the (Earth's) atmosphere and due to the lack of obstructing atmosphere, the stars we see are much brighter, but they do not twinkle," she says.

"Meanwhile, due to the absence of the atmosphere with its light scattering feature, the sky we see is not blue but is deep dark. And also I can tell you a wonderful phenomenon: we can see sunrises 16 times a day as we circle the Earth every 90 minutes," she adds.