Atlantis is scheduled to launch Oct. 8 for the highly anticipated mission to repair and improve the Hubble Space Telescope.
Gustav is a Category 1 hurricane with sustained winds of 90 mph and even stronger gusts. The National Hurricane Center warned this morning that Gustav is growing stronger and could be a Category 2 hurricane by the time it smashes into Haiti later today, which means it would be packing winds of about 100 mph.
It is expected to then turn toward the eastern tip of Cuba, threatening the U.S. military prison for terrrorists at Guantanamo Bay. Vulnerable to high winds are furling dozens of tents pitched on an abandoned runway where those attending war-crimes trials for alleged terrorists are housed. No hearings are scheduled this week.
At least one cruise ship in the Caribbean has headed to port in Mexico to get out of the way of Gustav's possible path.
Gustav's approach comes as Floridians are still mopping up after Tropical Storm Fay, which crisscrossed the state, leaving much of it underwater.
Weather has always been a problem for NASA. A freak hailstorm in 2007 peppered Atlantis' fuel tank with hundreds of small holes that forced NASA to ramp back the number of planned space shuttle launches that year.
In 2006, NASA took the unusual step of moving a shuttle from the launch pad back to the vehicle assembly building because of Tropical Storm Ernesto. When the storm track changed slightly, launch director Mike Leinbach ordered engineers to return the ship to the launch pad instead.
A space shuttle is protected somewhat on the launch pad by wind screens and the massive rotating service structure that surrounds the shuttle on the pad. But that wouldn't be much protection from a hurricane.
The astronauts assigned to the Hubble flight have been training for more than a year for this mission, and they are ready for their flight. This will be Mike Good's first space mission; he is a member of the astronaut class of 2000.
"I am excited. This is why we came here, this is what we have been waiting for," Good said. "It is over seven years now, so it is our turn. It is very exciting."
Good's Air Force call sign is Bueno. He will be teamed with veteran spacewalker Mike Massimino for both of his spacewalks to repair Hubble.
"We may be the visible ones -- the ones who are going to be out there. Actually, we get to go touch Hubble, open the doors and crawl inside, and that is very exciting," he said. "But none of it happens without the work here on the ground. There are teams at Kennedy that launch us and put the bird together. There are teams at the Johnson Space Center. There are teams at Goddard. It is just a great team effort."
This is an unusual team effort for teams at the Johnson Space Center and at the Kennedy Space Center, because they are getting two space shuttles ready to fly almost simultaneously. Atlantis cannot launch if Endeavour isn't ready to launch as well, because Endeavour will serve as the rescue vehicle for Atlantis.
The crew of Atlantis cannot seek "safe haven" aboard the space station if something happens to Atlantis after it launches and is on orbit. NASA has to have Endeavour ready to launch soon after Atlantis launches.
David Leckrone of the Goddard Space Center has been not-so-patiently waiting for Atlantis to launch to repair Hubble. The seven astronauts have a long to-do list when they get to the space telescope, and time is running out to repair Hubble.
"Of the six gyroscopes three have now failed. Its batteries are degrading. They are rechargeable just like in your cell phone but their ability to recharge gets les and less each time. Hubble also needs a new fine guidance sensor and we need to replace circuit boards in other instruments."
If only weather cooperates. NASA is used to dealing with hurricanes. Several of the space agency's centers are in the hurricane zone. The Kennedy Space Center has routinely closed due to hurricanes. Mission Control at the Johnson Space Center has implemented plans as recently as Hurricane Rita where it moves to a secret location in central Texas for operations. Hurricane Katrina nearly destroyed the operations at Michoud in Louisiana where the external tanks for the space shuttle are built.
The Associated Press contributed to this report.