David Saint-Jacques, shown here with crewmate Takua Onishi earlier in the mission, had been living at the underwater base since Oct. 20 and was supposed to be there for 13 days. ((NASA))

The approach of Hurricane Rina has forced Canadian astronaut David Saint-Jacques and five crewmates to abort a NASA mission designed to mimic the exploration of an asteroid.

The crew of the NEEMO 15 mission returned safely to shore in Key Largo, Fla., aboard support boats, NASA tweeted from its NEEMO Twitter account around 10:17 a.m. ET Wednesday.

"Crew sad to leave early, but feel we got a lot of objectives accomplished," Saint-Jacques tweeted earlier in the morning. NASA publicly announced the decision to recall the crew from their underwater lab, the Aquarius Reef Base, just before 7 a.m.

"Hurricane Rina just a little too close for comfort," it tweeted.

As of 11 a.m., the Category 2 storm packing wind speeds of 176 km/h was located east of Mexico's Yucatan Peninsula, about 800 kilometres, the U.S. National Hurricane Center reported.

The Aquarius lab is located 18 metres below the surface several kilometres offshore, which meant that its inhabitants had to undergo decompression overnight before surfacing to avoid getting decompression sickness.

Saint-Jacques, who has completed his astronaut training but not yet gone into space, was taking part in the mission with NASA astronaut Shannon Walker; Japanese astronaut candidate Takuya Onishi; Steven Squyres, an astronomy professor at Cornell University; and James Talacek and Nate Bender of the University of North Carolina Wilmington.

The six had been living at the underwater base since Oct. 20 and were supposed to be there for 13 days. NASA said the rest of the mission will not be rescheduled.

The goal of the mission was to simulate the exploration of an asteroid near Earth, including surveys using underwater submersibles to simulate spacecraft and the collection of samples by "aquanauts." As of Wednesday, the crew had conducted six underwater "spacewalks" and one day of scientific research inside the Aquarius habitat. They also completed four days of "scientific asteroid exploration" using the submersibles.