NASA has given the green light for space shuttle Discovery to land today, but forecasts of poor weather in Florida could force the craft to touch down in New Mexico, officials said."Based on the forecast, it's pretty obvious Northrup (the White Sands, New Mexico facility) looks the best," said Norman Knight, the US space agency's official in charge of the shuttle descent and landing. "But again, when we get closer to the deorbiting time, we have a better understanding of what the weather conditions are really at the site that would change that equation," he said.Based on current plans, Discovery would touch ground at White Sands in the western US state at the end of its 13-day voyage to the International Space Station.The shuttle and its seven-man crew initially were scheduled to land the same day at the Kennedy Space Center in Cape Canaveral, Florida in the southeast.NASA has a third alternative, Edwards Air Force Base in California.The landing will bring to an end the mission, which moved ahead the construction of the ISS. The Discovery team spent eight days at the station, rewiring it and attaching a massive truss.They also added a day and an extra space walk Monday to unstick a bulky old solar panel array, forcing it after numerous tries into its storage box so that a new larger array could be opened up fully.