MIAMI - Astronaut training has resumed at an undersea laboratory in the Florida Keys.
StartingTuesday, five astronauts began spending five days living and working atthe Aquarius Reef Base. While they're underwater, they'll be trying outan exercise device that could be used on the International SpaceStation and spacewalking tools.
They also will evaluate protocols for communications and for working with a remotely operated vehicle, according to NASA.
Scientistsstaying at Aquarius are called "aquanauts," and since 2001 their rankshave included astronauts training for space missions.
Astronauts last trained at Aquarius in June 2012 on a mission that simulated a visit to an asteroid.
Itseemed like the final astronaut training mission because Aquarius hadbeen set to close by the end of last year after losing its federalfunding to budget cuts.
This week's mission is the first at Aquarius since Florida International University took over its operations in January.
TheNational Oceanic and Atmospheric Administration owns the pressurizedlab that sits about 60 feet below the ocean's surface a few miles offKey Largo.
The43-foot-long metal tube - it looks like a yellow mobile home encrustedwith coral - allows scientists to live and work underwater for days at atime without coming up for air.
Formore than two decades, marine scientists have used the lab as a base tostudy changes in a coral reef and the populations of sea creatures thatcall it home.
Thebase allows researchers to scuba dive up to nine continuous hours a daywithout needing to return to the surface or decompress.
SixteenNASA Extreme Environment Mission Operations training missions were heldat Aquarius. NASA officials say the watery environment is similar to alow earth orbit and helps astronauts field-test their skills for spaceexpeditions.
Aquariusallows astronauts to physically experience life in tight quarters andpotentially hostile environments, said Tom Potts, the lab's director.
"The nice thing about Aquarius is that you don't have to simulate the danger," he said.
"The danger is real if you don't follow certain protocols."
The 400-square-foot lab accomodates six people and includes bunks and a small kitchen space.
Thecrew for this week's mission, dubbed "SEA TEST," includes NASAastronauts Joe Acaba and Kate Rubins, Soichi Noguchi of the JapanAeorspace Exploration Agency, and Andreas Mogensen and Thomas Pesquet ofthe European Space Agency.
The lab's next resident will be Fabien Cousteau, the grandson of ocean exploration pioneer Jacques Cousteau.
Witha team of filmmakers and scientists, Fabien plans to dive to Aquariusin November and spend 31 days doing research on the underwater effectsof climate change, and on the physiological and psychological effects ofprolonged confinement and long-term saturation diving.