Space Shuttle Discovery (Photo, courtesy of JSC)

The National Weather Service Spaceflight Meteorology Group (SMG) at NASA's Johnson Space Center (JSC) in Houston, Texas has been making preparations for the return-to-flight shuttle mission. The planned launch of Discovery (scheduled July 13 - 31) will mark the first shuttle mission since the loss of Columbia on February 1, 2003. SMG has embarked on several changes and improvements during this two year shuttle mission hiatus.

The primary change was implementing high-fidelity "weather-centric" simulations for both launch and landing. This has provided enhanced training for SMG meteorologists and key Flight Controllers who are involved with weather-related landing decisions. SMG also implemented a new Weather Users Forum to promote cross-discussion and information sharing between SMG meteorologists and the Flight Control Team members.

If all goes as planned, NASA's Return to Flight mission (STS-114) will take the crew of Discovery to their rendezvous with the International Space Station. The launch date is expected to be between July 13th and 31st. But even the best planning can't guarantee a sunny day and rain is not considered good luck for a launch. That's where SMG Chief Frank Brody and his team come in. One of the group's roles is to examine weather and climatology for launches and landings.

During the 1980s and much of the 1990s, when most missions weren't docking with a space station, climatology was a "prime factor" in selecting a launch window. Experts were free to set a launch window during a summer morning if the mission's science objectives allowed, knowing that thunderstorms are less likely in Florida at that time of day. But with the restriction imposed as a result of in-plane time, launch windows were reduced to five or 10 minutes per day, and climatology could not play as large a role in window selection.

In-plane time refers to the point when the plane of the International Space Station's orbit is over the Kennedy Space Center (KSC) launch site. Once rendezvous missions became the norm, weather -- the actual, real-time conditions at launch and landing sites -- became vitally important.

When it comes to evaluating launch day weather, Brody said that there are two sets of rules involved. One set is called the Launch Commit Criteria, monitored by weather experts, Air Force officials and launch controllers at Kennedy Space Center. The other set, the flight rules for an abort landing, are watched by SMG and JSC flight controllers.

Their job is to make sure conditions would be safe -- if the Shuttle had to make an emergency landing. This involves watching weather conditions not only at KSC, but also at possible landing sites in New Mexico, California, Spain and France.

"Basically, you can't launch unless you can land," Brody said. His team monitors conditions like cloud ceiling height, visibility, cross-wind speed and location of thunderstorms near all potential landing sites.

(Left to Right) Standing: Doris Hood, Brian Hoeth, Richard Lafosse, Frank Brody, Wayne Baggett, Karl Silverman, and Dan Bellue. Sitting: Tim Garner, Monica Sowell, Steve Sokol, and Tim Oram (Photo, courtesy of JSC)