KENNEDY SPACE CENTER, FLA. -- STS-120 Pilot George Zamka disembarks from the shuttle training aircraft, or STA, after successful landing practice on NASA's Shuttle Landing Facility runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Pilot George Zamka dons his launch and entry suit. He will join Commander Pamela Melroy in practicing landing on NASA's Shuttle Landing Facility runway in the shuttle training aircraft, or STA. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Commander Pamela Melroy disembarks from the shuttle training aircraft, or STA, after successful landing practice on NASA's Shuttle Landing Facility runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Seated in the cockpit of the shuttle training aircraft, or STA, STS-120 Pilot George Zamka is ready to begin landing practice on NASA's Shuttle Landing Facility runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Seated in the cockpit of the shuttle training aircraft, STS-120 Pilot George Zamka is eager to begin landing practice on NASA's Shuttle Landing Facility runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- The shuttle training aircraft, or STA, moves toward the runway on NASA's Shuttle Landing Facility. In the cockpit are STS-120 Commander Pamela Melroy and Pilot George Zamka, who will begin landing practice on the runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Seated in the cockpit of the shuttle training aircraft, or STA, STS-120 Commander Pamela Melroy is eager to begin landing practice on NASA's Shuttle Landing Facility runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Commander Pamela Melroy and Pilot George Zamka are suited in their orange launch and entry suits and on their way to NASA's Shuttle Landing Facility to practice landing in the shuttle training aircraft, or STA. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Commander Pamela Melroy dons her launch and entry suit. She will be practicing landing on NASA's Shuttle Landing Facility runway in the shuttle training aircraft, or STA. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- STS-120 Commander Pamela Melroy is eager to enter the shuttle training aircraft, or STA, to practice landing on NASA's Shuttle Landing Facility runway. A modified Grumman American Aviation-built Gulf Stream II jet, the STA simulates an orbiter's cockpit, motion and visual cues and handling qualities. In flight, the STA duplicates the orbiter's atmospheric descent trajectory from approximately 35,000 feet altitude to landing on a runway. Melroy and other crew members are at Kennedy Space Center to take part in the terminal countdown demonstration test, which also includes a simulated launch countdown. Mission STS-120 is targeted for Oct. 23. Photo credit: NASA/Kim Shiflett