HOUSTON -- The next crew bound for the International Space Station (ISS) is preparing for a mission that, they hope, will see the arrival of at least one space shuttle and possibly the addition of a third crewmember.

Cosmonaut Sergei Krikalev and NASA astronaut John Phillips, the crew of the Expedition 11 to the ISS, are gearing up for an April 15 launch to the ISS. The two space veterans are set to ride their Soyuz TMA-6 spacecraft into orbit and spend six months aboard the space station. During that time the space shuttle Discovery and Atlantis are slated to meet up with the orbiting laboratory.

"This is a very important step," said Krikalev, who is commanding the mission, during a press briefing here today.

Phillips will serve as NASA's ISS science officer and the expedition's flight engineer. He and Krikalev will relieve the space station's current crew, Expedition 10 commander Leroy Chiao and flight engineer Salizhan Sharipov.

Also launching with the Expedition 11 crew will be Italy's Roberto Vittori, an Italian Space Agency astronaut, representing the European Space Agency (ESA). Vittori's time in space will be brief compared to the Expedition 11 crew, just 10 days, during which time he will perform a series of experiments for ESA's ENEIDE science mission. The main objectives of the mission, which takes its name from the ancient poet Virgil's story of Aenaes, is for an ESA astronaut to complete major scientific programs on board the ISS.

Included among Vittori's many tasks is one technology experiment that will test the feasibility of detecting earthquakes before they strike through their effects on the Earth's magnetic field.

"It's the step before trying to prove this is possible," Vittori said of the experiment, adding that he also plans to take some time to look out the window during his short stay aboard the ISS. "We are concentrating this mission on technology demonstration."

Shuttle's return

According to NASA's current launch targets, the Expedition 11 crew will host not one, but two space shuttles during its six months aboard the ISS.

The missions mark the first shuttle flights to fly since the Feb. 1, 2003 loss of Columbia and its seven-astronaut crew. A chunk of insulation foam from the Columbia shuttle's external tank damaged its wing during launch, which allowed hot gases in during reentry, destroying the orbiter and killing its crew.  

Currently, NASA's first return to flight mission - STS-114 with the shuttle Discovery - is slated to launch between May and June of this year, with the STS-121 crew set for a July liftoff the aboard Atlantis orbiter.

"I am confident we're going to launch [a shuttle] in May or close to it," Phillips said, adding that renewed shuttle flights were 'absolutely essential' for the space station. "If it's delayed a month, that's okay, but if its doesn't launch at all the ISS will never live up to its potential."

Phillips and Krikalev will perform a number of new tasks to assist return to flight shuttle crews, including photographing the bellies of Discovery and Atlantis as they approach the space station to check their thermal protection tiles.

Preparing ISS for shuttle emergency

While NASA prepares the STS-114 mission for launch, the agency is also readying Atlantis in the off-chance that Discovery is damaged  and unable to return to Earth safely. Should that be the case, a contigency plan would call for the STS-114 crew to seek refuge aboard the ISS until Atlantis can be launched, a scenario the Expedition 11 crew has prepared for.

"There should be several factors that fail in a line for this to occur," Krikalev said, adding that while unlikely, the ISS would be unable to sustain an enlarged crew for long. "If it happened, it would have to be relatively short...for maybe several weeks we could deal with it, but we need to prepare backup plans for this scenario."

While fundamental concerns like food and oxygen were a concern, other factors, such as the health of a large 9-person crew in the relatively close quarters of the space station, need to be considered. More than just a backup shuttle - NASA officials hope to be able to launch Atlantis to retrieve a stranded crew within about 33 days - may be needed, he added.

"We may need to have more than one option," Krikalev said, adding that during past Russian Soyuz launches, another Soyuz was in line should the first mission need rescue.

Krikalev stressed that the safe haven concept, or Contingency Shuttle Crew Support (CSCS) as NASA calls it, is just one potential scenario.

"It's not the worst-case scenario, it's just one of them that is off-nominal," he said of providing safe haven for shuttle crews. "I think, as professionals, we ought to ber prepared for it."

Additional crew

Krikalev and Phillips may not be the only dedicated ISS crew to serve aboard the space station during their six month mission.

Original plans for their mission called for a third crew member to arrive during the STS-121 mission, possibly Russian cosmonaut Sergei Volkov or ESA astronaut Thomas Reiter, Krikalev said, adding that he and Phillips have trained with both men during their Expedition 11 preparation.

"It might be Sergei, it might be Thomas or it might be none," Krikalev told SPACE.com. "There are many options."

With the grounding of NASA shuttles since the Columbia accident, ISS crews have been reduced to two members - down from the typical three - due to limited supplies. That limitation has sparked a few firsts, including leaving the ISS empty of personnel during spacewalks and at least one unconventional spacewalk to work on U.S. station segments with Russian Orlan spacesuits.

Space station veterans

None of the Expedition 11 crew, nor Vittori, are no strangers to the ISS.

Vittori flew to the station as a visiting astronaut during a Soyuz taxi flight in April-May 2002 , while Phillips served aboard the space shuttle Endeavor's 12-day STS-100 mission to rendezvous with the ISS in April 2001.

"I actually get to go outside this time," Phillips said, who will perform the first two spacewalks of his astronaut career alongside Krikalev during the mission.

But it's Krikalev who tops the list with seven spacewalks and a total of one year, five months and 10 days of accumulated space time spread across five flights to the space station Mir, ISS and aboard the space shuttles.

"I think that the experience from those flights helps you to prioritize," Krikalev said. "I expect this to be a very interesting mission for two crewmembers and we will have to be efficient, especially when the [shuttles] come, since it will be more challenging to support return to flight."

  • Complete Coverage: ISS Expedition 11