Translation by Katy Gerstner An unmanageable wingless space vessel should be piloted by a computer. Aided by software from Delft, astronauts will try to get control of the landing back into their own hands.
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ESA astronaut Frank de Winne stares with intense concentration at the green light-emanating screen of the cockpit, his hand on the control stick. So far, the spaceship he’s piloting crashes during half of the landing attempts.
”Frank can really do it,” says TU professor, Dr. Max Mulder, a researcher in ‘avionics and man-machine interaction’ at the Aerospace Engineering faculty. He’s looking over De Winne’s shoulder behind the simulation cockpit. The astronaut’s hands give little nudges to the stick while the blue runway on screen rapidly approaches. A projected tunnel shows the route to be flown. Just in time De Winne pulls up. The landing succeeds.
”Works good this way,” says a satisfied De Winne, who hopes to become the second Belgian in space. De Winne was an experienced jet pilot before becoming an astronaut, so piloting a plane is no problem for him.
Atmosphere
De Winne regularly tests the piloting system developed by Mulder and his colleague, Dr. René van Paassen, for the space ship design HL-20. This wingless monstrosity should be able to return into the atmosphere from space. For instance, it could be used to save the crew of the International Space Station should a calamity occur.
”In the beginning, one hundred percent of all flights crashed,” says Mulder. He himself just crashed the HL-20. Few planes are so unwieldy. ”It most resembles a flying brick,” says Mulder sarcastically. ”The plane isn’t very aerodynamically sound. The steering controls are incredibly poor. Landing is a controlled crash in truth.”
Unfortunately, it’s inevitable that the HL-20 has such wretched steering controls. The vehicle has to be lighter than the space shuttle. It should fit well under the space station, and preferably it should be able to pass through the atmosphere without burning to a crisp. ”The plane is one big heat-resistant shield,” Mulder says. He shows a picture of the HL-20 design. It resembles a white deodorant stick with tiny little steering wings. The plane doesn’t have any windows, which provides better heat-resistance.
Threat
The HL-20 does have little booster rockets to help get it away from the space station, so that the plane won’t bump into it. After that it simply falls.
Whereas a normal plane descends gradually under an angle of three degrees respective to the runway, the HL-20 descends on a very steep path of twenty degrees. The hull itself functions as a wing, Mulder explains, but it isn’t a very good one. The carrying capacity is low.
Mulder explains that if your descent is less steep you lose too much speed due to air friction, which increases the threat of crashing. The last bit of the descent, however, has to be much less steep: one and a half degrees, to keep the plane in one piece when it touches down. ”So the trick is to know when to pull up,” Mulder says. There is in fact only one right moment that can’t be missed.
The obvious solution is to let a computer determine that moment, and so a different faculty research team is busy designing a fully automatic piloting system. ”But the idea bothers the astronauts,” Mulder reveals. ”Not many tests can be done for this type of space ship, and definitely none for the whole tripout of space. But the astronauts want to be able to trust it.”
Your skin
The potential emergency landers would like to have a manual override so that they can pilot the HL-20 themselves if they have to. This is also the reason for the involvement of astronaut De Winne in the testing of the equipment. If ever a rescue vehicle develops from HL-20, it could save his skin.
Because the HL-20 is so difficult to pilot, all possible piloting tricks must be employed.
For years, pilots have been flying with an artificial horizon, ”you know the kind from the flight simulators on your PC,” says Mulder. The boundary between the air and the ground lowers on your screen as the plane gains altitude. In a turn it tilts sideways. The plane itself is indicated by brackets.
The Delft man-machine specialists also have a lot of experience with the ‘tunnel in the sky’, a tube projected on the screen that the pilot has to fly through. This way the pilot can see the path he has to follow beforehand.
Added to this, the HL-20 has multi-stage controls. The control stick doesn%t steer the flaps of the steering wings directly. Instead, a computer calculates how a deviation of the stick can be translated into a fixed change in the angle of descent. ‘Fly-by-Wire’ is the name aviation experts give to a principle that’s been often implemented in aviation.
Blue
For the ESA astronauts in the HL-20, you need to come up with something better. One of the extra tricks Mulder and his colleagues used is a predictor % a little green symbol moving through the tunnel ahead of the pilot % that predicts where the plane will be in a few seconds according to the current course.
The predictor, in contrast to the classical artificial horizon, provides not only information about the condition of the plane at the moment, Mulder explains, but also information about the near future.
The pilot looks, via his computer screen, in the direction that the plane is dropping, not in a direction that%s fixed to the hull, as is usual. ”Your nose points all the way up, while the plane descends under a large angle. From a normal airplane window you would only see blue,” says Mulder. If the angle of descent changes at the end of the flight, the angle of vision changes with it, so that the runway stays in view.
His colleague, René van Paassen, co-designer and pilot, is beginning a new descent. The tunnel-in-the-sky dives into the depths to make a sharp curve close to the runway. Tensely Van Paassen follows the predicting green symbol. ”A bit more to the right,” he mumbles.
No mercy
”You have to steer it as little as possible,” Mulder explains in the meantime, ”for Christ sake leave it alone until you have to pull up. If you correct earlier, you drop out of the sky.”
But is that truly so horrible? The current rescue vessels simply fall the last stretch of the way hanging from a parachute. Isn’t that much safer than a risky landing?
”I guess so, but you can hardly control it, so it’s risky,” asserts Mulder. In the long run the plane also has to serve as a regular shuttle service to the space station. Mulder: ”If you want to go back and forth on a regular basis, you have to be able to land, not just flop down somewhere in the middle of the desert.”
First, however, the percentage of successful landings needs to go up. Fifty percent is not good enough, and the research continues. ”Maybe in ten years or so,” Mulder carefully predicts.
”O..o..o…help,” sounds come from behind the computer screen. After a while Van Paassen chuckles. ”We landed, but we don’t have any undercarriage anymore. I didn’t pay attention for a moment here,” he says, analysing his flight. ”As soon as you make a mistake, it’s too late. This plane has no mercy.”
An unmanageable wingless space vessel should be piloted by a computer. Aided by software from Delft, astronauts will try to get control of the landing back into their own hands.
ESA astronaut Frank de Winne stares with intense concentration at the green light-emanating screen of the cockpit, his hand on the control stick. So far, the spaceship he’s piloting crashes during half of the landing attempts.
”Frank can really do it,” says TU professor, Dr. Max Mulder, a researcher in ‘avionics and man-machine interaction’ at the Aerospace Engineering faculty. He’s looking over De Winne’s shoulder behind the simulation cockpit. The astronaut’s hands give little nudges to the stick while the blue runway on screen rapidly approaches. A projected tunnel shows the route to be flown. Just in time De Winne pulls up. The landing succeeds.
”Works good this way,” says a satisfied De Winne, who hopes to become the second Belgian in space. De Winne was an experienced jet pilot before becoming an astronaut, so piloting a plane is no problem for him.
Atmosphere
De Winne regularly tests the piloting system developed by Mulder and his colleague, Dr. René van Paassen, for the space ship design HL-20. This wingless monstrosity should be able to return into the atmosphere from space. For instance, it could be used to save the crew of the International Space Station should a calamity occur.
”In the beginning, one hundred percent of all flights crashed,” says Mulder. He himself just crashed the HL-20. Few planes are so unwieldy. ”It most resembles a flying brick,” says Mulder sarcastically. ”The plane isn’t very aerodynamically sound. The steering controls are incredibly poor. Landing is a controlled crash in truth.”
Unfortunately, it’s inevitable that the HL-20 has such wretched steering controls. The vehicle has to be lighter than the space shuttle. It should fit well under the space station, and preferably it should be able to pass through the atmosphere without burning to a crisp. ”The plane is one big heat-resistant shield,” Mulder says. He shows a picture of the HL-20 design. It resembles a white deodorant stick with tiny little steering wings. The plane doesn’t have any windows, which provides better heat-resistance.
Threat
The HL-20 does have little booster rockets to help get it away from the space station, so that the plane won’t bump into it. After that it simply falls.
Whereas a normal plane descends gradually under an angle of three degrees respective to the runway, the HL-20 descends on a very steep path of twenty degrees. The hull itself functions as a wing, Mulder explains, but it isn’t a very good one. The carrying capacity is low.
Mulder explains that if your descent is less steep you lose too much speed due to air friction, which increases the threat of crashing. The last bit of the descent, however, has to be much less steep: one and a half degrees, to keep the plane in one piece when it touches down. ”So the trick is to know when to pull up,” Mulder says. There is in fact only one right moment that can’t be missed.
The obvious solution is to let a computer determine that moment, and so a different faculty research team is busy designing a fully automatic piloting system. ”But the idea bothers the astronauts,” Mulder reveals. ”Not many tests can be done for this type of space ship, and definitely none for the whole tripout of space. But the astronauts want to be able to trust it.”
Your skin
The potential emergency landers would like to have a manual override so that they can pilot the HL-20 themselves if they have to. This is also the reason for the involvement of astronaut De Winne in the testing of the equipment. If ever a rescue vehicle develops from HL-20, it could save his skin.
Because the HL-20 is so difficult to pilot, all possible piloting tricks must be employed.
For years, pilots have been flying with an artificial horizon, ”you know the kind from the flight simulators on your PC,” says Mulder. The boundary between the air and the ground lowers on your screen as the plane gains altitude. In a turn it tilts sideways. The plane itself is indicated by brackets.
The Delft man-machine specialists also have a lot of experience with the ‘tunnel in the sky’, a tube projected on the screen that the pilot has to fly through. This way the pilot can see the path he has to follow beforehand.
Added to this, the HL-20 has multi-stage controls. The control stick doesn%t steer the flaps of the steering wings directly. Instead, a computer calculates how a deviation of the stick can be translated into a fixed change in the angle of descent. ‘Fly-by-Wire’ is the name aviation experts give to a principle that’s been often implemented in aviation.
Blue
For the ESA astronauts in the HL-20, you need to come up with something better. One of the extra tricks Mulder and his colleagues used is a predictor % a little green symbol moving through the tunnel ahead of the pilot % that predicts where the plane will be in a few seconds according to the current course.
The predictor, in contrast to the classical artificial horizon, provides not only information about the condition of the plane at the moment, Mulder explains, but also information about the near future.
The pilot looks, via his computer screen, in the direction that the plane is dropping, not in a direction that%s fixed to the hull, as is usual. ”Your nose points all the way up, while the plane descends under a large angle. From a normal airplane window you would only see blue,” says Mulder. If the angle of descent changes at the end of the flight, the angle of vision changes with it, so that the runway stays in view.
His colleague, René van Paassen, co-designer and pilot, is beginning a new descent. The tunnel-in-the-sky dives into the depths to make a sharp curve close to the runway. Tensely Van Paassen follows the predicting green symbol. ”A bit more to the right,” he mumbles.
No mercy
”You have to steer it as little as possible,” Mulder explains in the meantime, ”for Christ sake leave it alone until you have to pull up. If you correct earlier, you drop out of the sky.”
But is that truly so horrible? The current rescue vessels simply fall the last stretch of the way hanging from a parachute. Isn’t that much safer than a risky landing?
”I guess so, but you can hardly control it, so it’s risky,” asserts Mulder. In the long run the plane also has to serve as a regular shuttle service to the space station. Mulder: ”If you want to go back and forth on a regular basis, you have to be able to land, not just flop down somewhere in the middle of the desert.”
First, however, the percentage of successful landings needs to go up. Fifty percent is not good enough, and the research continues. ”Maybe in ten years or so,” Mulder carefully predicts.
”O..o..o…help,” sounds come from behind the computer screen. After a while Van Paassen chuckles. ”We landed, but we don’t have any undercarriage anymore. I didn’t pay attention for a moment here,” he says, analysing his flight. ”As soon as you make a mistake, it’s too late. This plane has no mercy.”
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