By Irene Klotz
CAPE CANAVERAL, Florida (Reuters) - I have watched as space shuttles nosedive toward the runway more than 100 times, knowing that there are no engines available to carry them back into the sky if something goes wrong.
When the ships glide home in a quiet countermove to their thunderous liftoff, it is not without drama.
Flawless touchdowns have come to seem routine since the inaugural shuttle flight in April 1981 but they are not a given. Landing safely is an overarching goal as NASA prepares for its final space shuttle mission -- and that is why Atlantis commander Chris Ferguson recently buckled in for his 1,400th or so practice run in a Shuttle Training Aircraft (STA).
I recently was among three reporters invited aboard the modified Gulfstream business jet that was a stand-in in for the shuttle on one of Ferguson's last training runs at the Kennedy Space Center in Florida. It was a rare chance to travel aboard a NASA aircraft, let alone one piloted by shuttle astronauts.
"It's a clean airplane, it likes to glide and it has good thrust," said veteran astronaut Ken Cockrell, who served as Ferguson's instructor. "We have to ruin all that to make it fly like a shuttle."
Our aircraft soared out over the Atlantic Ocean through the calm, moonless sky for Ferguson's first approach. The former TOP GUN Navy pilot was to make nine practice landings for the training run, bringing his STA training tally to somewhere in the neighborhood of 1,400 -- plus one actual shuttle landing.
The repetition is necessary because the shuttle drops through the air like a brick due to stubby wings that favor the aerodynamics of launch over landing.
"You don't fly your first (shuttle) flight until you've had 500 (STA) approaches," Cockrell said. "It's a dog-training routine. You do it many, many times until it becomes like the back of your hand."
At about 20,000 feet, I felt a gentle push out of my seat, a tantalizing sample of microgravity like the lift you get at the peak of a roller coaster ride.
Then we plunged toward the ground. The horizon, a thin ribbon of tangerine light left by the setting sun, twisted sideways in my window. Though we were warned about motion sickness, I felt only glee.
Ferguson was heading toward the shuttle's runway, a three-mile (5-km) concrete landing strip ringed by canals in the marshlands around the Kennedy Space Center.
Though the runway was illuminated by xenon floodlights, they were useless at high altitude. Instead, the pilot relied on other visual cues and navigation aids laid out along two pathways home -- one coming from the southeast, which ends on Runway 33, and one from the northwest to Runway 15. Shuttle pilots practice both approaches.
"It becomes like second nature so that when you become scared you don't have to worry about one part of it, which is how to fly the approach. You know it," Cockrell said.
For the third and fourth practice landings, I moved to the front of the plane and took up what I hoped to be a stable stance for the steep glides to come. To my left, I could see the handle that opens the stairway door, which Cockrell had warned us not to touch.
"It's possible that if you manage to get the door to crack open a little bit, the slipstream is going to pull it open and knock it off or something and you're going to go with it, so don't do that," he said.
Instead, I planted my left hand on the metal frame behind Ferguson's head, stepped my right leg back and bent my knees, praying I would not tumble into the cockpit. Then, the moment of microgravity lifted my whole body.
I managed some peeks through the windows before the rude slap of gravity returned my concentration to balancing.
As we careened toward ground, coming in seven times steeper than a commercial airliner, the runway looked impossibly small and surrealistic, a dollhouse version of real life.
Shuttle landings occur at about 230 miles per hour and it took us less than 30 seconds to reach that point after the STA started to dive.
We hovered over the runway, simulating the exact view that Ferguson will have when he makes the touchdown in the real, taller shuttle. Cockrell then pushed a button to take the plane out of simulation mode, returning the engines to forward thrust, and we swooped back into the sky for another run.
"Everyone remarks that when they get the chance to land the real orbiter, it's like flying the STA only smoother," Cockrell said. "The STA is a lighter airplane and tends to respond to gusts. You have to work harder to fly the path."
To mimic the shuttle, the pilot drops the Gulfstream's landing gear down when the plane is still flying at 288 mph, positions the plane to begin a dive and opens up thrust reversers, which redirect the engine exhaust forward, rather than back, slowing the aircraft.
With the plane now locked in shuttle simulation mode, it's up to the shuttle pilot to glide it back toward the runway.
"It's nothing like a night aircraft carrier landing -- I can tell you that -- but it's a good thrill," Cockrell said.
"It's fairly busy although once you've done it a few hundred times it's fun."
Ferguson and his crew are scheduled to launch Atlantis on July 8 for a 12-day mission at the International Space Station. The flight is the 135th and last in the shuttle program.
(Editing by Tom Brown and Bill Trott)