The U.S. space Agency, NASA, is putting space shuttle missions on hold until it finds out what caused the shuttle Columbia to break and burn Saturday, killing all seven astronauts on board. The decision could cause problems for the International Space Station, a large scientific outpost in permanent earth orbit. NASA uses shuttles to ferry crews to and from the space station.
The space shuttle Atlantis was scheduled to lift off on March 1st with a fresh crew and to resupply the International Space Station. Atlantis was also going to bring back the three astronauts, two Americans and a Russian, who have been living aboard the space station and conducting experiments since November.
That mission has now been put on hold until NASA officials have a better idea of what went wrong with Columbia.
In January 1986, after the space shuttle Challenger blew up moments after lift-off, killing seven astronauts, NASA imposed a moratorium on shuttle flights that lasted almost two years.
Joan Johnson, a space expert at the Navy War College in Rhode Island, said this time around, it's unlikely NASA will keep the shuttles grounded for long.
"In 1986, it was a different set of circumstances. They did not have the imperative to get a shuttle flying again, certainly that the international space station gives them. But clearly, NASA will not fly if they have any doubt whatsoever about the safety of the vehicle," said Joan Johnson.
Sixteen countries are partners in the International Space Station, which first went into orbit 1998, but is still under construction. When completed, the space station will measure 110 meters from end to end and weight more than 408,000 kilograms.
Many experts, including aerospace specialist Marcia Smith of the U.S. Congressional Research Service, are concerned construction of the space station will be compromised. But Ms. Smith said it's likely Russia will be able to fill the gap in the short term. "One of the advantages of Russia joining the space station partnership in 1993 was that they can also take crews and cargo to the space station instead of just space shuttles. But their space craft for taking cargo up to the space station is much smaller than the shuttle," she explained. "So, there would be issues about how much cargo could go up. And their space craft cannot bring anything back. And one of the advantages of the shuttle is it can bring stuff back as well."
In terms of the immediate future, the International Space Station's three astronauts have enough supplies to last them until June. And, if necessary, they could return to earth aboard a Russian Soyuz escape vehicle attached to the station.