NASA's decision to delay the launch of the first space shuttle flight in two-and-a-half years poses no threat to the International Space Station or the two astronauts on board, an agency spokeswoman said Tuesday.
The station was to have received fresh supplies and a replacement gyroscope via space shuttle Discovery last week, but a glitch in one of the shuttle's fuel sensors has grounded the flight indefinitely.
The station crew -- United States' John Phillips and Russia's Sergei Krikalev -- are now focusing on day-to-day tasks while they wait for NASA to attempt another launch, according to NASA spokeswoman Kylie Clem at the Johnson Space Center in Houston.
"They're pretty adept at changing when things like this come up," said Clem. "They're doing some extra science experiments this week."
Krikalev and Phillips took a brief excursion outside the space station early Tuesday morning, when they sealed themselves in a Soyuz space capsule and moved it from one of the station's ports to another.
The move gives the astronauts more room to carry out a future spacewalk. The Soyuz maneuver had originally been planned for August, but mission controllers bumped it forward after they learned of the delay with Discovery.
NASA officials say they're hopeful that the agency can repair and launch Discovery by the end of July. But given that NASA technicians have yet to figure out what's wrong with the shuttle's fuel sensor, it's possible that the launch could get pushed into the next window, which opens Sept. 9.
(The launch windows are based on the position of the space station and NASA's requirement that the shuttle lift off in the daytime.)
Discovery is the first shuttle NASA has tried to launch since Columbia broke up upon re-entry to Earth's atmosphere in 2003. The accident killed all seven astronauts aboard.
Should the launch get rescheduled for September, the space station crew is in no danger of running out of food or oxygen, according to Clem. The Russian space agency regularly sends supplies to the station on unmanned Progress cargo ships. A new ship will arrive in August -- whether the space shuttle gets off the launch pad by then or not.
As for the replacement gyroscope that the shuttle was to have delivered, the station can survive a little longer without it, said Clem.
Gyroscopes help keep the station from tumbling out of control. Originally, the station had four, but one broke in 2002. A circuit breaker on a second one failed in March.
The station is now running on the absolute minimum of two gyroscopes. Should another one fail before the shuttle arrives, mission controllers will have to rely on the station's thrusters to keep it oriented.
Thrusters aren't ideal because they burn fuel and limit where the crew can go during spacewalks. But staying ready for whatever happens is just business as usual, said Clem.
"We've been operating this way for the past two-and-a-half years and preparing for this option," she said.
