KENNEDY SPACE CENTER (AP) - Waving tiny American flags as they left crew quarters, the seven Discovery astronauts are hoping to declare independence from gravity with launch attempt number-three today. Forecasters put the weather odds at 80 percent go, although there is concern for crosswinds at the emergency landing strip should the shuttle need to make a quick landing. Engineers earlier ruled that a small crack in the insulation of the shuttle's big fuel tank was not a cause for concern. And NASA says an inspection at the pad today showed no other problems. Discovery is set to deliver a new crew member to the International Space Station, along with needed supplies. Astronauts will also test safety procedures developed in the wake of the Columbia disaster in 2003. This is only the second mission since then.