The Atlantis Space Shuttle is set to launch today at 11:26 a.m. EDT.   This historic flight, the last of the Space Shuttle program, will be watched by thousands of people in Florida and many more remotely online and on TV.

All of the astronauts are abroad Atlantis.   The Close Out Crew is excepted to soon complete the final checks.

However, there is a 70 percent chance that unsuitable weather will prevent the launch of the Atlantis Space Shuttle. 

Kathy Winters, shuttle weather officer, said a tropical wave from the Caribbean is expected to hit Florida with a lot of tropical moisture.

Today, the chance of no-go is 70 percent.  Chances of no-go are 60 percent for Saturday and 40 percent for Sunday.  

Shuttle launch delays are not uncommon.  A 2007 Associated Press analysis found that only 40 percent of space shuttles launched on time.  Of the failures to launch on time, about one-third is due to weather.

The failure to launch on July 8 (and especially of it also fails on the next two attempts) will undoubtedly disappoint many viewers, particularly those who made the trip to Florida to catch the action.

Moreover, it will likely cost NASA about $1 million for each failed attempt.

Still, having the right weather is (literally) a matter of life and death.  The 1986 Challenger disaster was likely caused by low temperatures that exacerbated a design flaw in the rocket booster.

Click here to catch the Space Shuttle launch action live online.