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No. The ISS always has at least one Russian Soyuz spacecraft docked to it, for the purpose of evacuating in the event of a major problem with the station, or in the case of a tragedy like this. The Soyuz is a capsule-type craft; the section that returns to Earth is bell- shaped, and can touch down on land or, if necessary, water. Depending on how long the Shuttle fleet is grounded, odds are this is how the current in orbit Expedition Six crew will return to Earth, and at the time of this how their replacements will arrive.
According to current ISS support plans, it is expected that in late April or early May the Soyuz TMA-2 will dock with ISS and deliver the Expedition 7 crew. Shortly afterwards, the Expedition 6 crew will land on Earth in the Soyuz TMA-1 currently at the station serving as an escape capsule. In the event of a continued delay in Shuttle flights, plans call for more Expedition teams of two to be ferried to ISS via additional Soyuz TMA-series spacecraft to essentially stand watch on the ISS until Shuttle flights resume and a full Expedition crew of three is delivered.Bottom Line: At this time, there's no need to bring the Expedition Six crew down. They have plenty of supplies, the ISS is in great shape, and a Progress resupply module successfully docked with ISS on 2/4/03
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How will the crews be swapped out on ISS until Shuttle flights resume?
The Russians are expected to provide crew exchange support using their Soyuz TMA series of spacecraft. Although no plans have been officially announced, space policy experts believe the Russians will launch a Soyuz to ISS in early May of 2003, most likely with only an American astronaut and a Russian cosmonaut aboard. This would serve two purposes:
1) To furnish the station with a new Soyuz lifeboat.
2) Allow the current Expedition 6 crew of Ken Bowersox, Don Pettit and Nikolai Budarin to return to Earth aboard the Soyuz TMA-series spacecraft already docked to the station.
However, one of the limiting factors in staffing and maintaining ISS is that basic mission requirements currently limit Expedition crews to a minimum of three crewmembers. The reason for this limitation is that on any spacewalk, an EVA cannot consist of less than two people going outside while a third remains inside to coordinate the EVA and to assist the two spacewalkers in both donning and removing their spacesuits.
On 2/24/03, a three-hour drill was conducted by Bowersox and Pettit to see whether the two could put on their spacesuits, follow a detailed protocol for avoiding decompression sickness, then shed the bulky EVA suits without the assistance of a third crewman. Pettit, being more slender than the commander, managed to get out of the suit with relative ease. Bowersox, using support straps inside the airlock in an innovative manner, developed on-the-fly a new method of removing a spacesuit without any additional assistance from a second person.Although results of this test were considered by ISS Flight Controllers as successful, the official vindication of the plan to reduce ISS staffing to a maintenance crew of two came on 2/28/03, when NASA announced a revised Expedition 7 crew roster. Although
neither NASA nor the Russian Space Agency (RSA) have made any official announcement, it is expected the crew will consist of Russia's Yuri Malenchenko and NASA's Edward Lu. This will be the second trip to ISS for both, having visited during one of the early assembly missions in September of 2000. Lu and Malenchenko performed a six-hour-plus EVA to connect power, data and communications cables from the Russian-supplied Zvezda Service Module and the rest of ISS.
Both Malenchenko and Lu are reportedly undergoing a revised training regimen at Star City in Russia, along with Alexander Kaleri and Michael Foale. Kaleri and Foale are now tentatively scheduled to replace the Expedition 7 crew later in the fall of 2003. On a side note, Malenchenko, Lu and Kaleri already were in training to replace Bowersox and company in March of 2003 as the Expedition 7 crew, and were originally scheduled to ride Atlantis into orbit.
On 3/28/03, an unidentified spokesman for RSA announced 4/26/03 is the target date for the first replacement mission, with the official crew announcement being scheduled for 4/18/03.
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The space station has two large engines that can be used to do a reboost, using fuel from the station's onboard tanks.
Russia has an unmanned cargo spacecraft called Progress which can carry fuel, food, and other supplies to the station. Most of the time, space station reboosts are performed by the Progress's engines, to save the space station's own engines from wear.
Europe is building a resupply spacecraft of its own, which will be able to carry much more cargo and fuel than the Progress. It is due to enter service in a year or two.