Washington, June 25 (IANS): NASA will send an international crew to the bottom of the Atlantic Ocean this summer to prepare for future deep space missions during the 14-day NASA Extreme Environment Mission Operations (NEEMO) 20 expedition to begin from July 20, NASA said in a statement.

NEEMO 20 will focus on evaluating tools and techniques being tested for future spacewalks on a variety of surfaces and gravity levels ranging from asteroids to the moons of Mars and the Martian surface.

"The NEEMO team is particularly excited about this mission as it is a huge milestone to have achieved 20 missions at Aquarius over the past 15 years," said Bill Todd, NEEMO project leader.

"Living and working in the highly operational, isolated and extreme environment of the aquatic realm has provided significant science and engineering for the benefit of human spaceflight. It has also clearly proven to be as close to spaceflight as is possible here on the Earth," Todd said.

The mission will test time delays in communications due to the distance of potential mission destinations.

They will also assess hardware sponsored by the European Space Agency (ESA) that allows crew members to read the next step in a procedure without taking their hands or eyes away from the task using a tablet, a smartphone and a head-mounted interface.