The Associated Press
Even with its shuttles grounded, NASA can easily retrieve the astronauts aboard the international space station using Russian vehicles.
A Soyuz vehicle attached to the space station could bring the three astronauts onboard back to Earth at a moment's notice. But if the space agency's remaining shuttles are out of service for an extended period in the wake of Saturday's catastrophe, as seems likely, it could prove difficult to maintain the station's operations.
"This is clearly a big setback for station because during the rest of this year shuttles were supposed to carry up lots of big pieces of hardware for assembly," said John Logsdon, director of the Space Policy Institute at George Washington University.
NASA plans call for expanding the space station during five shuttle flights this year. On the next flight, scheduled for launch March 1, shuttle Atlantis has orders to deliver supplies and scientific equipment. Subsequent missions this year call for installing a framework of external trusses and solar arrays.
With Russia's ability to launch supply vehicles to the international station already compromised by budget problems, the loss of U.S. space shuttle Columbia could seriously jeopardize the continued operation of the outpost.
With no permanent crew aboard, the space station can operate in a "dormant" mode as long as occasional maintenance is performed by visiting astronauts. In fact, NASA had already been considering a "demanning" contingency for 2003 before Saturday's events.
But the longer the station went unoccupied, the greater the chances that it would deteriorate to an uninhabitable state. A dormant period would also cause a significant interruption in the station's continuing assembly and scientific research program.
Expedition Six, as the current crew is called, arrived at the station in November and is scheduled to return to in March. The crew consists of NASA astronauts Ken Bowersox and Don Pettit and Russian Soyuz commander Nikolai Budarin.
The Columbia shuttle mission that tragically ended Saturday over eastern Texas did not visit the space station. But the crews of the two spacecraft did speak by telephone on Jan. 28, the anniversary of the Challenger disaster that killed seven astronauts 17 years ago.
An unmanned supply vessel was to be launched Sunday from Russia's Baikonur Cosmodrome. It was scheduled to arrive at the orbiting station Tuesday.
(Complete Columbia coverage at Cincinnati.com)
Tristaters shocked, seek answers
Terrace Park man loses friend on Columbia
Tristate Jews stunned by Israeli's death
India natives offer special prayers
KIESEWETTER: Another tragedy unfolds on TV
PULFER: Flight: a routine miracle
Enquirer seeking local connections
Disaster evokes Challenger image at Wright-Pat
School superintendent's hometown in debris path
Local woman witnessed 'perfect' launch
Ohio astronaut: `Oh, my God'
List of Ohio astronauts
Space program must go on, scientists say
DeWine: NASA funding will be rexamined
Reading firm makes shuttle fuel tanks
Archived video & special coverage from WCPO
Did NASA underestimate left-wing damage?
Body parts reportedly found
Columbia, crew of 7 lost
Families' pride turns to anguish
Texans saw trails in sky, heard booms
Final words: Astronauts gave no warning of disaster
Americans gasp, cry at news
Americans have taken space flights for granted
Bush consoles shuttle families, country
Text of Bush's remarks
Terrorism ruled out
Crew biographies: First Israeli aboard
Independent board to investigate
Landings were early safety concern
Challenger explosion recalled
Painful memories for teacher's hometown
Deadly accidents in space exploration
Former astronauts search for explanation
Space station crew won't be stranded
Timeline of Columbia flight
Columbia was NASA's oldest shuttle
Key dates in space program
New NASA administrator faces big task