WASHINGTON: The upcoming eye wearable device Google Glass is "not an optimal tool" for handling operational procedures and tasks in a simulated space environment, NASA astronauts have revealed.

In a latest series of experiments, astronauts spent several days inside an underwater lab and performed multiple tests using both Google Glass and an iPad.

They found that iPad provides features readily adaptable to support operational tasks in space.

"Google Glass is a promising technology but needs to overcome battery life, display viewing and scrolling issues in order to be an operational useful tool," Space.com quoted astronauts as saying.

In its current configuration, Google Glass was useful for data collection but for current operational procedure/task completion, it is not an optimal tool, they added.

Glass scored highly on video recording taking photos but scored poorly in areas like "reading".

The tests were part of NEEMO 18 - NASA's latest underwater "extreme environment" mission off the coast of Florida, reports added.

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