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a cautious flight instructor would think are fine for a student’s first solo flight. Just because a shuttle’s rockets are powerful enough to accelerate it straight up from the launch pad to faster than the speed of sound in less than a minute doesn’t mean it can bull its way through the weather. The February 24 to March 9 flight of the Shuttle Discovery—its last before retirement to a museum—helps illustrate why astronauts, shuttle flight directors, controllers, and others involved with shuttle flights need to be weather wise. Some of NASA’s strict launch and landing criteria ensure that the shuttle won’t trigger a lightning stoke, as airplanes do regularly. Others require avoiding rain because at the shuttle’s launch speed, raindrops would be like bullets hitting the thermal tiles that keep the spacecraft from burning up when it reenters the atmosphere at the end of a flight. In addition to lightning and precipitation constraints, shuttle launch rules require that clouds, which cover foureighths or more of the sky (broken or overcast) be at least 5,000 feet above the ground and that the visibility be at least 4 statute miles. These rules ensure that if something goes wrong during the first four minutes after launch, the booster rockets on each side of the orbiter and the huge external fuel tank would be ditched, and the pilots would land the orbiter at the Shuttle Landing Facility—the 15,000-foot Runway 15/33 built for shuttle landings at Kennedy. (This has never happened.) Ever since the United States. first started sending people into space in the early 1960s, NASA’s astronauts, flight directors, and flight controllers have relied on National Weather Service meteorologists at what’s now called the Spaceflight Meteorology Group (SMG) at the Johnson Space Center in Houston. In addition, the Air Force’s 45th Space Wing Weather Squadron produces observations and forecasts for many shuttle operations at Kennedy. For launches, the Air Force forecasts for the launch pad while the SMG forecasts for the runway.

WEATHER-RECON PILOTS In addition to direct links to meteorologists who understand what they need, shuttle astronauts have a source of weather information other pilots could only dream about: Another pilot—an astronaut—checks out the actual weather beforehand at and around the launch and end-of-mission landing sites. For Discovery’s February 24 launch the “weather astronaut” was Lee Archambault, who had been the pilot on the June 8-22, 2007, Atlantis flight and commander of the March 15-28, 2009, Discovery flight. The weather reconnaissance pilot collects more detailed data than forecasters have from satellites, radar, and other sources. While the shuttle’s ceiling limit is higher than a flight instructor would require for a solo, the shuttle’s limits of a crosswind component of up to 15 knots and moderate turbulence would make a flight instructor cancel a first solo.

On February 24 Archambault took off in one of NASA’s T-38 jets about three hours before the scheduled launch to check the winds and weather around Kennedy. “We were concentrating on a band of clouds to the southeast over the water, which could lower the ceiling if they moved in,” he said. After landing the T-38 again, he took off an hour and 45 minutes before the launch in the training aircraft to fly approaches to runways 15 and 33 in order to experience what Discovery’s pilots would find if they had to make an emergency landing back at Kennedy. The training aircraft is a Gulfstream II business jet modified to fly like the shuttle on an approach from approximately 35,000 feet down to a landing. Archambault reported to Discovery’s Capcom (capsule communicator) in Houston that conditions favored Runway 15 for an emergency landing. Whether it’s an emergency landing or a normal end-of-mission landing, shuttle

LEE ARCHAMBAULT prepares for his June 2007 flight as pilot of the space shuttle Atlantis in the mockup trainer at the Johnson Space Center.

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Flight Training - June 2011

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