With Discovery's almost flawless performance, NASA is confident the shuttle will be ready for the December 2006 launch of the  STS-116 mission. Shuttle officials expect to use at least 110 days, plus extra five days if necessary, preparing Discovery for its next launch window on December 14.

"That’s a very challenging flow for us," Stephanie Stilson, NASA’s flow manager for Discovery. "We are going to do the best we can to get everything done in the time allotted…it’s very important that we launch in December if we can and we’re going to do everything we can to get there."

But even before that, the Discovery must also be launch-ready as a rescue ship for NASA’s planned shuttle mission STS-115 aboard Atlantis on August 28. NASA’s window for the STS-115, which will deliver a new solar array to the station, was reduced by a week due to a schedule clash with the planned Russian Soyuz launch of the station’s Expedition 14 crew.

Russia’s Federal Space Agency is hoping it will be able to send Expedition 14 commander Michael Lopez-Alegria, flight engineer Mikhail Tyurin and Japanese space tourist Daisuke Enomoto toward the ISS aboard via a Soyuz TMA-9 spacecraft on September 14. But this is doable only if NASA launches Atlantis on or before September 3, NASA officials said.

"We don’t want to have dual operations at the station with both the Soyuz crew and the shuttle crew at the same time," said William Gerstenmaier, NASA’s associate administrator of space operations. "We just can’t have that many folks on the space station doing the diverse tasks that are there."

After two consecutive failures to launch because of bad weather conditions, on July 1 and 2, NASA's STS-121 mission is said to be "go" for the third time this July 4, 2006. "We're go to continue with the launch countdown," William Gerstenmaier, NASA's associate administrator of space operations, "I don't think we're taking any additional risks than we did in our original [flight] assessment."

Foam has been a long issue for the Discovery. This time there is too much foam loss, approximately less than one-tenth of an ounce. It fell from the uppermost bracket connecting a 17-inch liquid oxygen feedline to Discovery's orange external tank.

Although officials say that it is less than 50 per cent of the acceptable launch debris standards, there could be an ice build up of up to 0.0024 pounds and could fill the divot left by the liberated foam piece. Ice is also a potential launch debris risk.

NASA has been working on how to go around the foam issue for three years now. If you remember, this kind of matter caused the Columbia to sustain sizable damage during it's launch in January, 2003.

Discovery is now back on track to launch NASA's STS-121 mission on July 4. Liftoff is currently set for 2:37:55 p.m. EDT (1837:55 GMT), with current weather forecast predicting a 60 percent chance of favorable conditions for flight.